In this episode of the Flex Diet Podcast, I sit down with Dr. Nathan Jenkins to discuss how to improve performance, body composition, and long-term health through the lens of aerobic development and metabolic flexibility. Nathan shares his journey from exercise physiology and coaching CrossFit athletes to his new role teaching physiology at the University of Georgia School of Medicine. We discuss why metabolic flexibility is such a powerful framework for understanding everything from biochemistry and exercise performance to metabolic disease. We also dive into interpreting maximal exercise testing data, including VO₂ measurements, EKG analysis, and near-infrared spectroscopy (NIRS), along with how different energy systems work together during training and competition. Nathan explains why building an aerobic base is critical for repeated high-intensity performance, how pacing impacts outcomes, and why the ability to "suffer" is actually a trainable skill. To wrap up, we cover practical strategies you can apply right away, including prioritizing protein and carbohydrates, improving sleep quality, and addressing common micronutrient deficiencies through blood work, such as magnesium, vitamin D, and omega-3 status.
In this episode of the Flex Diet Podcast, I sit down with Dr. Nathan Jenkins to discuss how to improve performance, body composition, and long-term health through the lens of aerobic development and metabolic flexibility.
Nathan shares his journey from exercise physiology and coaching CrossFit athletes to his new role teaching physiology at the University of Georgia School of Medicine. We discuss why metabolic flexibility is such a powerful framework for understanding everything from biochemistry and exercise performance to metabolic disease.
We also dive into interpreting maximal exercise testing data, including VO₂ measurements, EKG analysis, and near-infrared spectroscopy (NIRS), along with how different energy systems work together during training and competition. Nathan explains why building an aerobic base is critical for repeated high-intensity performance, how pacing impacts outcomes, and why the ability to "suffer" is actually a trainable skill.
To wrap up, we cover practical strategies you can apply right away, including prioritizing protein and carbohydrates, improving sleep quality, and addressing common micronutrient deficiencies through blood work, such as magnesium, vitamin D, and omega-3 status.
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Dr Mike T Nelson: [00:00:00] Welcome back to the Flex Diet Podcast. I'm your host, Dr. Mike T. Nelson. On this podcast, we talk about all things to increase performance, improve body composition, add muscle, do all of it in a flexible framework without destroying your health. Today on the podcast, I have a good buddy, Dr. Nathan Jenkins, and we're talking about all sorts of great stuff.
A little bit more on the, I'd say kind of the aerobic side, but everything from how to teach exercise physiology, some, uh, tidbits on CrossFit nutrition, energy systems, buy-in for doing, uh, cardio, VO2 max work, suffering as a skill, heat acclimi- acclimatization, metabolic flexible frameworks, body comp, protein, sleep, omega-3 testing, blood work, you name it.
We are all across the board [00:01:00] here, and I think you'll really enjoy this. So Dr. Nathan Jenkins is an exercise physiologist, research educator, and human performance coach. Nearly two decades of experience in exercise science and sports nutrition He's formerly a professor at University of Georgia, was formerly a coach with RP Strength, and I worked with him at Rapid Health Optimization, so I got to know him there where he did a lot of the blood work and other work there.
And now he is do- taking a new job as a faculty at the University of Georgia School of Medicine as an associate professor of medical education. So super stoked for him on his new job, and I think you'll really like this one if you're into body composition and performance. We do get ultra nerdy at times, but that's all right.
It's fun. If you want more information from myself, make sure to check out my newsletter. Go to miketnelson.com/newsletter. You can hop on there, [00:02:00] get on the fitness insider completely free. Wanna let you know that the Flex Diet cert will be opening up again in June. This will open on Monday, June 15th, so if you want more information, hop on to...
The newsletter's gonna be the best place for that. It'll be open for exactly one week, until June 22nd, 2026. And if you want more information from Nathan, he does have a little bit of information, um, on Instagram. But other than that, he is one of these people who is pretty quiet in the background, but super knowledgeable.
He's been working at the intersection of coaching and physiology for a long time, so I think you'll really enjoy this chat with Dr. Nathan Jenkins.
All right, and welcome to the podcast. How are you today, doc?
Dr Nathan Jenkins: Hey, Mike. Uh, Dr. Mike, I'm doing great, man. Thank you for having me.
Dr Mike T Nelson: Well, yeah. Thank you so much for having you on here.
And I know... Well, by the time this comes out, this will be public, [00:03:00] but you have a brand new job coming up. Um, I got to know you a little bit through- Mm-hmm ... work at Rapid and, and Arete- Mm-hmm ... which has been amazing, and- Yes ... now you're gonna be teaching some med students, I hear.
Dr Nathan Jenkins: Yeah, man. Uh, yeah, and it's... I, I mean, it's already, I guess, public in the sense that I posted on my Instagram a couple weeks ago, but the, um, new position starts, it's effective June 1.
We're c- a couple weeks away from that at the time of this recording. Um, but I'm making my, uh, I don't know if you call it triumphant return- ... a return, a return of sorts into the academic space. So previously, I was a, uh, professor of, uh, I guess I was in, I was in the kinesiology depart- department. Uh, exercise physiology is my historic kinda background, um, with a- Um, focus on cardiovascular physiology, metabolism, and nutrition, and kind of the intersection of all of those things.
I focus a lot on, like, integration across a lot of different systems. Um, [00:04:00] that was a nine-year tenure, uh, that I had with U- University of Georgia is where I, where I worked. Um, and then, uh, this is a little bit of introduction for your audience who I 100%- Yeah, perfect ... will, will not n- know exactly who I am, uh, but, uh, um, at least most of them probably won't.
But, um, then about f- along the way, uh, if your audience will probably be familiar with a, a, a company, a brand in the space called RP Strength. Yep. Um, I was- Had a chat with
Dr Mike T Nelson: Nick on their podcast a couple times, which
Dr Nathan Jenkins: was great. Yeah, I've heard, I've heard you on, on their podcast, so I'm really close with those guys, Nick and Dr.,
the other- Yeah ... Dr. Mike. Um, so I was, I was there, I was a nutrition coach with them from about 2018 until 2025, till, until last year Um, s- focusing on, like, my niche client base f- with that group was, uh, people who trained CrossFit, uh, and similar, like, hybrid, kinda call it training [00:05:00]methodologies that needed, um, support from a nutrition standpoint.
Um, so that kind of blended some areas of expertise for me, and that was a good niche for me for many, many years. Um, so when- Did you just yell
Dr Mike T Nelson: at them and tell them to eat more sweet potatoes? That's what I
Dr Nathan Jenkins: did- No ...
Dr Mike T Nelson: with all my CrossFit people back in
Dr Nathan Jenkins: the day. Yeah, a lot. Yeah, for sure. Lots of sweet potatoes.
You don't have to- So the CrossFit crowd, you don't have to convince them too hard or twist their arms too hard to eat more sweet potatoes. Yeah. Because that's, like, cl- historic, quote, unquote, "paleo," which is- Yeah, yeah, yeah ... where a lot of those folks come from. Yep. So what I will more yell at people to do is to, first and foremost, freaking, you don't eat...
Most of you aren't eating protein like you think you, like you think you are. Yep. So there's that. And then don't be afraid of the, um, the non-paleo carb sources for- Yeah ... um, you know, certain co- for certain contexts and in, and the right, appropriate dose. Um, so I, I did more of my yelling about that.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: And then also-
Dr Mike T Nelson: I would just ask them what their favorite foods were. Like, one guy- Mm-hmm ... told this story multiple times on the podcast. He's like, "Donuts." Great.
Dr Nathan Jenkins: Yep.
Dr Mike T Nelson: At the end of the day, you're a professional [00:06:00] CrossFit athlete. You're training two times a day, three times a day sometimes. Yeah. You don't have a job.
Yeah. This literally is your life. Yeah. I'm at the gym. You live that, literally.
Dr Nathan Jenkins: Yeah.
Dr Mike T Nelson: Um, have two donuts at the end of the day. So he went on the Instagram or whatever it was back in the day. Yeah. Took a picture. Like, the whole internet, like, lost its mind. They're like, "You're a dumbass." Yeah. "You're telling this guy to eat donuts?"
I'm like, he was eating 3,500 calories of, like- ... this was back when paleo was, like, all the rage of- Yeah ... really good foods- Of freaking sweet potatoes ... high nutrition-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: sweet potatoes, vegetables. And I'm like-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: he, he can't eat any more of that food, and- The volume was- ... he is so low- Yeah ... on calories.
Yeah. He's like, "Yeah, man, as soon as I started eating donuts, all my lifts went up." I'm like, "Yeah, it's 'cause you need more
Dr Nathan Jenkins: calories." Yeah, because... Well, it's, yeah, the trade-off of, of, of, uh, volume versus density, like- Right ... right? And that's, um, what we... That's a balancing act for everybody across the spectrum, so yeah.
Um- Anyway, I interrupted
Dr Mike T Nelson: you.
Dr Nathan Jenkins: Continue. Yeah, that's okay. No, no, we can... This is... There, I, I, I... Listen, man, I love, I [00:07:00] love getting on podcasts because, you know, it's long-form, and we have the time and, and, uh, breathing room for this kind of stuff. So, um, yeah, but, like, just a q- d- without... I don't wanna lose your audience either, like going through droning on about my background, but the, uh- Uh, the, I took a break, I guess is, is now how it's working out to be.
I, I didn't know what ... if, if there was ever going to be a time I would return to, to academia. I always kind would, uh, said that I would've wanted to. But when my son was born, I effectively, uh, this is now four, he's four as of a couple weeks ago. Oh, wow. Um, yeah, yeah. He's a little guy. Uh, but when he was, when he was coming along, I ha- I effectively, I had two very, very busy, very highly demanding of my time full-time jobs.
The, the academic thing and the consulting coaching thing that was on the side with RP, which is where that, you know, was entering in the, the background. And so, um, I had this, like, really wonderful, um, I guess blessing, uh, but diff- like also challenging kind of moment [00:08:00] where I had to decide, like, I can't sustain this and have a newborn, so I need to step away from one or the other.
And after much consideration and, and it, like, it was kind of difficult, but step away from the tenure. I was tenured, you know, at UGA. Oh, that's even so much harder to leave then, man. Oh, yeah. 'Cause they had the ultimate kind of safety net, safety net and job security.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: Uh, but also the other side of it was like, you know, there's the, the professional stuff, which is like, you know, the harder I work, the, the better job I do for my clients, kind of the better, like the income and all that kind of stuff tends to be, which was and turns out continues to be true.
But then also, like, there's the time, like, when you have a, it's, it's, I'm sure there's plenty of parents on this podcast. I had the luxury of like- Making that choice is like, I can actually still do a really good job with my work, but more important, I can be there as a, you know, as a father for, you know, these years that are so quick, and now he's four.
And like, so these last four years have been like from the infancy stage now to like he'll be starting pre-K and- Oh. You know, [00:09:00] in the next couple months. Um, and so the timing of this, of this job transition works out for me in like a really, you know, profound way, uh, a, a wonderful way. I can... It, it, it makes sense.
Like, he's gonna be as- now, like starting in August and f- and onward, he will be, you know, the t- the traditional school day structure. Yeah. It kind of makes sense for me to get back, like if I'm gonna do it. And so this, so this job, this, um, so the... and l- the last thing I'll mention for this context is, uh, it's a really cool thing, like, um, l- local kind of inside baseball.
Most of your listeners won't care about this, but for, for me and for like the community here where I live and the state, I would say, it's kind of a big deal. So the University of Georgia is the flagship institution of our state, and I have a big history. Like I have two degrees from there, and then I was a professor there for nine years.
And now this year in 2026, we're finally, finally after so many years opening the UGA School of Medicine.
Dr Mike T Nelson: Oh, that's
Dr Nathan Jenkins: awesome. And yeah, it's, it's like it's a really... Like the g- the [00:10:00] state government, the governor, the state, uh, legislature is like pumping a ton of money into the effort, and it's been a lot of build up over like the last 15 years and, um, you know, it's just really fucking, uh, can I...
I don't know if I can swear on the podcast. No, you're good. Okay. Uh, it's, it's, it's humbling and it's, it's special for, for me to like, be part of like the new faculty, uh, group that's kind of coming on board with that. So anyway, yeah, that's, that's what I'm getting into here in my next chapter is, um... So long story short is having been in academia, stepped away for a while to do the industry st- stuff and coaching and consulting and then going back to, um, a- and, and to, to the academic space in what is my passion, which is a teaching role.
So, you know, in my previous iteration, I did do the whole like research, the R1, I directed a research lab. I had NIH grants, published, we published a ton of papers, um, did that whole thing and I... That was cool. Um, that kind of, you know, got my name in lights on that stuff, which I don't really care about. But, uh, now [00:11:00] returning back to like what I fundamentally am super passionate about, which is education.
So yeah, really, really excited and, uh, honored to, to, to do it. So anyway, that's way too long, but that's my, that's my little story and, uh, yeah, happy to dig into, you know, specific content today, uh, that will be beneficial to your audience, um- So, which I know is all about metabolic flexibility and all those things- Yeah
that you, uh, you know, have a lot of expertise in, so.
Dr Mike T Nelson: Yeah, and it's so cool that I'm always biased because, I mean, my PhD was in exercise physiology and metabolism. Mm-hmm. The- Yeah,
Dr Nathan Jenkins: we have very similar, we have a similar background, yeah.
Dr Mike T Nelson: Yeah, yeah. That those people are teaching medical schools. Uh, the other guy I think of too is my buddy, um, Dr.
Dwayne Jackson, who taught- Mm-hmm ... medical schools I think at Yale for many, many years. And- Cool ... definitely more on the hardcore physiology exercise, I would say, background- Mm-hmm ... although not formally. Because it, it gives you a, I think a better [00:12:00] perspective of physiology altogether. 'Cause I think if you, if you were to poll most people, they're like, "Oh, so exercise physiology, you just talk about sports enhancement all the time."
Yeah. And I'm like, "Not really. It's just that exerci- or that physiology at rest is just boring." Like, once you apply a- It's... Mm-hmm ... a stimulus to it- Yeah ... like exercise is a stimulus, then all sorts of crazy things happen. And if you can understand- Absolutely ... it from at rest all the way up to max exercise, my argument is you have a really good understanding of just physiology-
Dr Nathan Jenkins: Of physiology
period. Yeah. Yeah. Yeah. So the way I always thought, like I always think about it is, uh, physiology at rest, like you said, it's boring, it is unchallenged.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: It is not- It's always the same too. And, and it's more or less always the same. And that is this condition in which most, going back to like who I'm thinking about a lot now is the medical students, most of their evaluation, uh, when they're future clinicians, is [00:13:00] going to be of their patients in that unchallenged physiological state at rest.
Yep. And so I'm not- Or challenged by disease of some form. But yeah, they're at rest. For sure. They're not on the treadmill. But yeah, so but, but a lot of those diseases too that they're, that they're presented with clinically will not manifest fully until they're... the, the, the s- the, the, their patient, uh, that that physiology is challenged.
Yep. By, by exercis- exercise is a great way to do it, uh, to, to unmask pathology, um, uh, of metabolic origin or otherwise. Uh, but that- most of the time that's like, that, that's not... Like, that's obvious to, like, me and you and to- Yeah. ... to, to your colleague that you were just talking about, the, the Yale professor.
Um, but it's not obvious to, it's not obv- it's not obvious to the general public, I don't think, at all.
Dr Mike T Nelson: Mm-hmm.
Dr Nathan Jenkins: And certainly not, and it's not to, you know, most, most physicians. And so, um- Yeah, that's something that's, like, super... But it's, but, but the f- it's so intertwined. Like, it's all, like, like you said, so the, yeah, oh, [00:14:00] you're an exercise physiologist, so y- you just, like, test athletes.
Well, I do, sure, but that also, uh, the physiology that I see in testing that athlete gives me a lot of insight into the other end of the s- the spectrum when things are not dialed in and are not physiologically sound, when they are pathological. Because you see the, the... It's all, it's all part of the same continuum.
You see certain physiological readouts at one end and physiological readouts at the other. One you call optimal fitness, and the other you call disease. And, um, it- but it's all part of the same physiology, so I think that's... I, I love that stuff, um-
Dr Mike T Nelson: Yeah. And I think, and this is right up your alley, too, but, like, an exercise stress test.
Mm-hmm. That's it, yeah. You know, like, for listeners, what are you doing? We're doing an old school 12-lead EKG or some form of an EKG. Mm-hmm. Yeah, you can do it at rest. Like, you can see, oh, wow, ooh, ST segment elevation. Ooh, not so good. Like, there's definitely things you can pick off on a 12-lead. Mm-hmm.
Great. Yeah. But we know that if we put the person on a treadmill and we exercise them [00:15:00]and we apply a stressor to their system with the same 12-lead, we're not even doing echo- Mm-hmm ... we're not doing anything else- Yes ... we can find and reveal something that we did not see at rest. Yes. Yep. Which to me, I think is missed by a lot of medical community, period, even though those tests have been done for long, long time.
They're not anything
Dr Nathan Jenkins: new. Yes. Yeah, that, that one in particular is a great one that I... You know, again, I'm not actually in those cla- that classroom yet, but that's one that, um, does present an opportunity to, like, start, start developing in students that way of thinking, because it is part of their- Yes
standard curriculum. Yes. It's like, "Hey, guys, let's, let's talk about why the exercise stress test is something that you..." Like, it's, I think, uh, I'm still learning the standards for the exams they're gonna take, 'cause I, again, uh, you and I, we're PhDs, not MDs, so- Yeah, I didn't do a med school. I, yeah, I haven't, I haven't totally...
I'm still, like, that's on my to-do list, like, my mission for, like, the first year that I'm in that environment, is really understand what the [00:16:00] exact, like, um, you know, the, that step one exams, step two exams, like, those exams that they have to take, what the, what the specific learning objectives are. But I'm quite confident that some pathology that is unmasked by that exercise challenge on the, the classic exercise stress tests from a cardio, uh, cardiology standpoint.
The premise is, is that at rest, the echocardiogram- Can look completely normal, but up-upon challenge, increase, increase, uh, basic-- fundamentally with the, the, the, the purpose of the exercise in that context is to increase, uh, myocardial metabolic demand. And in the face of that increased energy flux through the myocardium, it could reveal a, uh, an electro, an electrophysiologic abnormality that can then be picked up on that 12 lead.
And that can be, that as itself can be diagnostic and inform the physician for like, "Okay, what do we need to do for this patient?" And it can guide their treatment. [00:17:00] Or it could say like, "Hey, look, in, in the past you've had a heart attack" Yeah. "That you did, that you may not have known about." Like, there's a bunch of different scenarios in which, you know, that, that test can be profoundly informative for everybody involved, for the clinician, for the patient, for their family, you know, like to, to, to do so.
Well, it turns out that that, that's, that one is part of like standard practice, which is awesome. And there's a lot more room for that kind of like g- impose a physiological challenge of some kind, disrupt homeostasis, s- observe how the system responds and, you know, go from there. Like where versus like, you know, crash into the primary care office, take blood pressure.
It's high because you're nervous, you know, like that kind of stuff. Um, there's just so much more room, like more room for, uh, clinical judgment If we, uh, have this, you know, broader understanding of physiology, you know?
Dr Mike T Nelson: Yeah. I mean, I would make the [00:18:00] argument that, again, this is an exercise-based answer, but for total risk factors, the, the two things I would look at is obviously a good blood work panel.
You either can go down, multiple down that pathway. Yeah. You've done a lot of that work. Which, which we've done that, yeah. I think super, super useful, relatively easy to get, just give some blood, et cetera. Mm-hmm. The harder one is I would make a very good argument for a max exercise test. I would do a 12V EKG.
I would do a full metabolic card. Mm-hmm. You could go as far as stick a NIRS device on them, you know, however crazy you wanna get with it. Yeah. But if you really understand everything from the raw data that comes off of there- Mm-hmm ... I just think that is a massively diagnostic, not even performance, just diagnostically of what's going on- Mm
with that person, if you only had to do one active test.
Dr Nathan Jenkins: Yeah, the, the max test?
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: For sure. Yeah, man. I-
Dr Mike T Nelson: What are your thoughts?
Dr Nathan Jenkins: Yeah, I mean, yeah, for sure, [00:19:00] and I love, I mean, super interested. You, you mentioned, uh, you mentioned the, the NIRS, uh-
Dr Mike T Nelson: Yeah ...
Dr Nathan Jenkins: device. So where would you, where would you place it, and what would you look for?
Dr Mike T Nelson: So I would do it on the main... So there's a huge debate on that, right? So- Right ... I would probably do a three set up and do one on the, the right vastus, so the right quad, left quad, and then probably on a, a quote, "non-working muscle," like the lateral deltoid. Sure. And so, and then the high level, I'm looking at left versus right differences, how fast are they basically.
So the NIRS device, for listeners, will tell you SMO2 basically. It may tell you blood flow. We can debate if that's accurate or not, but literally you stick it on there, and how much oxygen is the muscle actually using? Mm-hmm. And if that is plummeting really fast, I would argue that they're becoming more anaerobic sooner than they probably would need to.
Mm-hmm. If there's a [00:20:00] difference left and right, there's almost surely a difference mechanics-wise, recruitment, et cetera. For
Dr Nathan Jenkins: sure. For sure.
Dr Mike T Nelson: Yeah. And then the non-working muscle gives you an idea of- Are you trying to move blood flow somewhere else as a compensation? Mm-hmm. So in theory, it shouldn't really change much.
It's not the main working muscle, but as you get closer to max, if you see a massive change in blood flow there, you could argue maybe your cardiac system isn't up to par, maybe it's blood flow dynamics, but you're basically trying to steal blood flow away from another muscle to achieve- Yeah ... the outcome.
Dr Nathan Jenkins: Yeah, um, 100%, uh, that, yeah, and I've done... It may not show up too much if you, like, search me on PubMed or whatever, but I've done just enough work with NIRS to be dangerous.
Dr Mike T Nelson: Yeah, me too.
Dr Nathan Jenkins: Uh, right. Right, right, right. Uh, near-infrared spectroscopy, for the n- listeners who aren't familiar, it is, um, basically using infrared, infrared light scattering through the tissue to get an [00:21:00] index, an idea of how much oxygen the muscle's using.
Um, and there's a lot of, there's a lot of assumption involved with that, and there's a lot of- Oh, yeah ... physiological pr- parameters, like how thick the adipose tissue is is a big one. Um, so, so, so those technical caveats aside, it, and I'm also speaking to the listeners who actually know or think they know f- things that are g- they go, like, come at us in the comments.
Uh, you know? And, um, yeah. Oh, you get the
Dr Mike T Nelson: hardcore NIRS people, and they're like, "Oh my God," like- It's- ... after listening to them, and they're not necessarily wrong. It's like-
Dr Nathan Jenkins: Oh ... "
Dr Mike T Nelson: Oh my God, I'd, I would never get any data ever from anyone." And I, and I get it- Right ... what you're, you're saying in terms of reproducibility and stuff.
Mm-hmm.
Dr Nathan Jenkins: Exactly. But
Dr Mike T Nelson: I'm just looking at gross throwing darts at a wall, man. Correct. Yeah. Did you start at 85% and end up at 11, or did you start at 70- Mm-hmm ... and end up at 50, you know? That's, like,
Dr Nathan Jenkins: what I'm looking at. Right, right, as far, yeah, as far as tissue saturation, yeah. Yeah. Yeah, that's all, that's all, like, yeah, a c- a complete...
So going bigger, like zooming out to the bigger picture, you asked my thoughts on the whole paradigm- Yeah, yeah ... of, of max testing [00:22:00] and EKG, so, so the full VO2, like metabolic, uh, expired gases analysis that you can do Yeah, there's, uh, a- and then the, the EKG and the NIRS, like, so you're getting, so you're getting whole body, uh, cardiorespiratory responses with insights into things like ventilatory/anaerobic threshold.
You're getting, uh, significant cardiovascular, uh, and cardiac and myocardial, uh, and electrophysiological parameters of, of the, of the heart itself. And then you're getting some peripheral indices from the, from the NIRS device, so on the working muscle and non-working muscle. Yeah, that's a really, really, really rich data set.
And, um, the, the only, the only, uh, I guess, for want of a better term, critique, but that's not the right way to put it, is it just requires a super... For, if one person's gonna interpret all that, that requires a, an uncommon level of expertise. So it's like- That's the
Dr Mike T Nelson: hard part ... that's the hard- It's the [00:23:00] interpretation- Mm-hmm
because-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: as you know, you've looked at a ton of that data, too. Like, I get a lot of weird case requests, and my first thing is, "Send me all the raw data from the metabolic cart." Like, I don't want your interpretation. Just give me- No ... literally the spreadsheet- Just the- ... with all the shit- Mm-hmm ... in it.
Because-
Dr Nathan Jenkins: Yeah, the,
Dr Mike T Nelson: the,
Dr Nathan Jenkins: the breath by breath, if
Dr Mike T Nelson: you
Dr Nathan Jenkins: have
Dr Mike T Nelson: it, right? Breath by breath. Yeah. I don't want any, I don't want even any averages. If you did breath by breath, great. Give me breath by breath. We can sort through that later.
Dr Nathan Jenkins: Yeah.
Dr Mike T Nelson: But to, 'cause that's how I did it, was looking at raw, the raw data and creating your graphs and looking at ventilatory- Yeah
changes, the respiratory rate- Yep ... whatever.
Dr Nathan Jenkins: Yep.
Dr Mike T Nelson: But a lot of the newer people I work with are like, "Oh, but the machine said this or that," and it, it's- Yeah ... "It determined this." I'm like, "How do you know that's right?" You have to look at the raw data and then know that if this factor is off, then, well, I'm gonna look at this.
Like, for example, with NIRS. Mm-hmm. If the NIRS does something really goofy, I'm probably gonna look at respiratory rate. If your respiratory rate spikes and you're fricking hyperventilating like crazy, that's gonna change your [00:24:00] local CO2, which changes the Bohr effect, which changes, potentially, your SMO2 also.
Dr Nathan Jenkins: 100%.
Dr Mike T Nelson: Right. Oh, yeah. Yeah, yeah. So, you know, knowing how all those things play off each other gives you where to look to see what's going on. But, I mean, shit, that took me decades to probably figure all that- For sure ... shit out, you know?
Dr Nathan Jenkins: Yeah. Oh, man, you mentioned the Bohr effect, and then you got me salivating.
Oh, I freaking love it, love it. I, and I'm just, I'm so pumped to get back in the classroom and, like, really dive into this kind of stuff. Um, we, I was, I would love... This, this was one that should have, we should have, like, a quiz or, like, an exam at the end of the episode.
Dr Mike T Nelson: Yeah. Um, to- 'Cause everybody thinks CO2 is, like, some evil molecule right up there with lactate And I'm like, "No, they're just, they're, they're signaling molecules, they're byproducts."
It's how, it- They, you know- It's, yeah ... now we're learning they do all sorts of beneficial stuff.
Dr Nathan Jenkins: Well, just the, like to, to the, to the, to the point of the Bohr effect, it's making things more facilitative for oxygen delivery under metabolically distressful con- conditions.
Dr Mike T Nelson: Yes.
Dr Nathan Jenkins: Um, it's- Explain the Bohr effect
Dr Mike T Nelson: for people who are listening before we lose
Dr Nathan Jenkins: everybody.
Yeah, [00:25:00] it's basically, it, it shifts, it's, it's, it's the phenomenon whereby the affinity of, uh, hemoglobin for oxygen changes under certain conditions. So basically more is, more the acidic environment, um, the, the less affinity hemoglobin has for oxygen, meaning that it facilitates the offloading of oxygen at the tissue where it's needed.
Um, so a lower, like people are like, "Wait, a lower affinity?" Like lower, um, affinity is another big word, sorry, how attracted these two molecules- Mm-hmm ... are for each other, right? So under, uh, uh, conditions of metabolic acidosis, which occurs during high-intensity exercise, right? We got proton buildup and all that.
More acid, literally. More hydrogen- More- ... ions running around ... quite literally a more acidic environment. That ch- changes the, as I understand it, now I'm not a biochemist, and Mike, you can correct if this is wrong, but my understanding is it actually physically changes the conformation of the hemoglobin molecule.
That's my- Such- ... understanding too, yeah ... such that it is, it's the holding onto it not quite as tight- Yeah. Less sticky ... [00:26:00] under, less, less sticky, exactly, um, uh, compared to baseline conditions, like homeostatic conditions. Again, going back to the, the, the original kind of point that we were talking about is like, uh, under normal resting physiology, these things are not tested.
Well, now we're testing it. Um, now we're challenging the system. Well, one of the things our, our, our bodies are amazing machines, these amazing things, and at the molecular, cellular and molecular level, in this case we're talking about the red blood cell and the molecular level being the hemoglobin molecule that it contains, um, it's again, under conditions of metabolic acidosis, it's less sticky for oxygen, meaning that when you get the, the red blood cell goes to where it's supposed to go, which is the muscle tissue, and, and, and we'll get to everywhere, but to muscle tissue in the context of exercise, it's more readily giving of that oxygen molecule so that it can be used to, for oxidative phosphorylation and production of ATP b- via the, um, [00:27:00] oxidative pathway And that is a wonderful phenom- like, so going back, like, so we hope we don't lose everybody, but, like, CO2 buildup and a proton, uh, production through the, um, high intensity, the, the, the, the metabolic pathway that's most predominantly associated with high intensity, uh, sprint and sprint endurance type work, the glycolytic pathway, that triggers this change to therefore support also...
It's funny, it's like highly glycolytic activity supports aerobic metabolism in this way.
Dr Mike T Nelson: Yes.
Dr Nathan Jenkins: Uh, which is, which is phenomenal. Like, isn't that, isn't that fun?
Dr Mike T Nelson: Um- Yeah, because, uh, I mean, you were probably taught this too, and I, I was too, and I had to unlearn it, was that everything operates in a silo. Like, we were taught the whole thing of like, here's all your aerobic metabolism.
Mm-hmm. Here's all your anaerobic metabolism. Right. Here's the Krebs cycle. Here's this, here's that. And, and you, you [00:28:00] walk away going, "Oh, okay." But it... Luckily, later, we- I had some classes where you, you know, try to piece these things together via per- performance and-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: the story I've told multiple times on the podcast, that I'm sure people are tired of hearing, was the first time I ever saw a demo of the Moxy device was at, in Austin with, um, Aaron and Ben House.
Guy gets on the rower, warms up, stick the little sensor on him. It's, like, 85%, cool. Has him do a Wingate, so 30 seconds, just hammer it, like, as hard as you can for 30 seconds- Yeah. Love them ... on the Concept2 rower. Love the Wingate. And I'm watching it.
Dr Nathan Jenkins: Okay. 30, okay.
Dr Mike T Nelson: Wingate And I'm watching the SM02. At the end, he hits, like, 13%.
Okay. And I'm like Oh, wait. Oh, oh, what, what just happened? Like, I was told this is anaerobic exercise at these very short durations, that we're not using oxygen. Mm-hmm. Now you're telling me you stick a sensor on this muscle, and it's telling me that it used a shit ton of oxygen- Mm-hmm ... during this event.
So I'm like, [00:29:00] either that sensor's a piece of shit or everything I learned was not really correct. Yeah. And then later I met Roger who runs Moxy and, you know, ended up buy- I have three of them and multiple different ones. Yeah. And I'm like, yeah, the sensor's pretty damn accurate. I was like, what I learned was not the complete story.
Dr Nathan Jenkins: That's right. That's right. It's that it's using... It's u- like, well, y- I don't wanna take the take away- No, go ahead ... from you, but, but it's that y- yeah, yeah, the, the, the, the metabolic demand exceeded the capacity of the oxidative system, as evidenced by the fact that it was being maximally tapped, you know, tapped out.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: And therefore, where... The way I would put it to students when I was teaching exercise physiology, and I very much intend to put this to the medical students when I get the chance to, is like, okay, the basically the per- the, that individual's at their VO2 max, but if we look at the... And, and we can associate a work capa- a physical work capacity, we can put a wattage-
Dr Mike T Nelson: Yep
Dr Nathan Jenkins: to their VO2 max, and yet they are [00:30:00] performing at a wattage, at a power output that is in excess of what would be associated with their VO2 max number. Yeah. Like, let's call their VO2 max 50 or whatever, pretty trained person. Um, but their VO... Like, if you do the wattage, you do that calculation, the ACSM calculation or whatever, the wattage would put them at a VO2 max of 60 or 65 if they could sustain this, but it's only for 30 seconds, which is another conversation.
Mm-hmm. But, but okay, well then how are they able to do that work? Well, they're getting ATP. Well, where are they getting the ATP from? They must be coming from somewhere. It, it, and then you put it to the students like, "Well, they're at VO2 max. It must... Is it the oxidative pathway?" Well, no, that's maxed out.
They're doing above the... So with that, that delta, the difference between what they're are predicted to do at their VO2 max versus what they're actually doing, as measured by the machine, where's that ATP coming from? Ah, that must be the glycolytic pathway, right? Because it's the what is required for power outputs that are over and above what can be sustained by the oxidative system.
And [00:31:00] that's what you were seeing, I would say, you know- Yeah ... uh, in real time there. That's pretty cool. So they were- Yeah ... completely depleted a- according to the, to the Moxy, which by the way, we use that, we use that same device as well. Uh- Oh, okay. Cool ... yeah, we, uh, in, in research setting, it's, uh, it was pretty cool.
Um, and, uh, by and large, as far as devices go, like, that one's pretty easy to, to work with. Um- Yeah, it's not bad. The interface- So it's- ... is a little kludgy, but seems to be- Yes ... reproducible in my experience. That's right. That's right. Um, but yeah, so like, okay, the muscle is clearly showing like basically call it damn near zero- Yeah
physiologically speaking, oxygen levels. Um, and yet they're still able to do work. If they're, uh, and more so metabolically, where c- does that work come from? That's where we see these, this concept of the in different energy systems coming to life right before your eyes in a physiological context, as opposed to, like, a biochemical.
Not to take anything away from the bio- the beautiful- Yeah, yeah ... biochemistry of it all, but the, like, in a physiolo- like, an actual, somebody in front of my eyes [00:32:00] doing a, like in this case it was a Wingate, um, doing physical work. How do we make sense of that metabolically? I love that, I love that stuff, so.
Dr Mike T Nelson: Yeah, and that's what really, I realized, oh, everything we learned is not necessarily wrong, just incomplete, and like how you think about it is different. Mm-hmm. Mm-hmm. And also that, I don't know how many people I've had send me all this data and I'm like, "What was the freaking outputs on all these tests you did?"
And like- Mm-hmm ... it's gotten better, but like half the time they're like, "W- w- well, I don't know. I got the nearest device, I got this, I got that." I'm like- Mm-hmm ... "But, but like, what was the physical output?" Like you- Yeah, what's the work? ... you got it on the machine. Like, the machine tells you- Right ... all these things.
Dr Nathan Jenkins: Right.
Dr Mike T Nelson: And even if you have no technology, like you're a trainer listening to this and you're like, "Man, I just barely got a heart rate strap." If you monitor heart rate and output, you can get really, really far in making improvements in athletes and making inferences- Oh ... and a bunch of other stuff. Yeah.
But if you- Yeah ... don't measure the output and you [00:33:00] just only use RPE, like you're gonna be so lost in four weeks.
Dr Nathan Jenkins: Super lost. Yeah, and let me actually, that's a good, that's a good point, Mike, to actually, like, if we- we've gotten like, I don't know, already, we've talked for like 35, 40 minutes or something.
Very easy for a couple PhDs from an academic background to- ... to get, to get like s- five, six, seven layers to the onion deeper than any coach is ever gonna use in working with a client. And just to speak to that part of your audience, listen- You don't really need all this science stuff- No ... in my opinion most of the time.
I have it, and it's
Dr Mike T Nelson: cool, but I,
Dr Nathan Jenkins: I don't- Yeah ...
Dr Mike T Nelson: I can also use it without it, too.
Dr Nathan Jenkins: Right. But, but the things that I think that c- coaches absolutely need, to your last point, is a measure of output, which I'll define as some measure of human performance.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: Of, of, of real world, like, if it's athletic performance, like, freaking, like, mile or 5K times, or 2K row.
You know, pick your pla- like, um, whatever it is. [00:34:00] A strength metric. It doesn't really matter. Like, whatever, whatever it is for that athlete, for that context. If it's a everyday client, it's something that they care about. A CrossFit benchmark workout, which is something that I've used with clients quite a bit.
Um, c- couple that with something that's easy to monitor, either, like, physiologically. Mm-hmm. Like, maybe it's heart rate, maybe it's, uh, I, honestly, man, I don't know what you think, but RPE goes a long way. Um- Oh, it's super helpful when done correctly. Yeah, no question. Exactly. Like, RPE is a big one. Like, okay, I felt, I felt, uh, better even...
Or I felt just as bad, but I l- but I got two more reps on this workout, or shaved a couple sec- like, oh, my negative splits were more consistent. That's a big one for me with endurance stuff. Yep Anyway, yeah. That kind of stuff c- act- actually, from a physiological standpoint, in my opinion, captures the whole summary very, very practically, without having the, the need to get into the weeds that we, that we're, that we like to get into.
Um, but [00:35:00] for the higher level practitioner to, to have, like, the five, six, seven layers of onion, of, of the onion, like, deep of knowledge, to have that but never really need it with your client, that's a, that's a weapon, you know? That's a fricking, like... That's, um... You know, I usually only go, like, one or two layers with a client, but, like, I have this deeper context that informs, like, every little thing that I do, or, and big, and especially the big things that I do with clients, you know?
So, um, yeah, that's, that's the reason for this, like, kinda nerding out on all this stuff is we don't get to very often, number one, so it's fun, and number two- Yeah ... it actually d- it actually does form the foundation of, of, um, you know, things that we recommend for folks, you know?
Dr Mike T Nelson: Yeah. And it, it, it is helpful to a degree, and that's why, I mean, I'm biased 'cause I have my own stuff, but I have the whole flexible meathead cardio course-
Dr Nathan Jenkins: Right.
Right. Yeah ...
Dr Mike T Nelson: that I did, and I wanted to make it useful and give all the protocols and all that stuff, but I realized when doing that I was... I kinda thought and tested it through a few trainers and I thought, "Well, I can start it at, at this level." And I [00:36:00] realized- Mm-hmm ... no, because a lot of them don't have any formal training.
They're very educated in terms of materials and things they've learned, and very motivated and are doing better, but I had to go all the way back to, like, let's start at cardiac output. What is cardiac output? Mm-hmm. Like, because if you're- Mm-hmm ... missing some of those basic things, like, you don't need them on a day-to-day basis.
Right. But when you're troubleshooting and you're, you're trying to think your way through problems you've never encountered, 'cause you can never- Mm-hmm ... give enough examples to cover every case-
Dr Nathan Jenkins: Right.
Dr Mike T Nelson: Right ... then you can go, "Oh." And sometimes you end up all the way back there. You know, sometimes you just- Mm-hmm
look at it and go, oh, you're doing, you know, 30 second repeats or whatever. Mm-hmm. And interval four through six you just go off a cliff. Mm-hmm. I'm probably wondering what's your aerobic base? Oh, it's 32- Yes ... milliliters per kilo per minute.
Dr Nathan Jenkins: That's right.
Dr Mike T Nelson: Sure. Sure. It's probably shitty to do this kinda work.
It's terrible,
Dr Nathan Jenkins: yeah. Right?
Dr Mike T Nelson: But you're, you only get there by knowing that, oh, because your aerobic system is what's supporting- [00:37:00] Mm-hmm ... that system during the rest periods- Yeah ... during the recovery- Yeah ... things like that. The recoveries.
Dr Nathan Jenkins: Mm-hmm. Mm-hmm.
Dr Mike T Nelson: But that allows you then to be like, "Okay, let's do some of these.
Let's keep the quality high, and let's do more VO2 max work or other things here that-" Mm-hmm ... "on paper don't look related, but are actually physiologically directly related to the issue you're trying to solve."
Dr Nathan Jenkins: 100%. And that speaks to another point that you were making a minute ago, which is, like, how things are- And the same as, same as what you shared is true for me in my, in my training to a, to a point, and then actually did get some good training in this later on.
But it is how things are traditionally taught as, like, very siloed and segmented.
Dr Mike T Nelson: Mm-hmm.
Dr Nathan Jenkins: Um, like you said, it's like all anaerobic, it's all aerobic. It's kinda like this dy- this dichot- dichotomous thinking always, right? But it turns out that there's layers and layers and layers of connection between things, and the, the, the, the interval work and then the rec- the, the...
And I, I, and I don't know, I haven't actually seen your [00:38:00] course, Mike, but I- my guess is that, right, my educated read of, like, the, the description that I've seen on your website is, like, that, the... What is it? Cardio for meatheads?
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: It's like, basically, if you shore up your aerobic base, then your ability to recover between hard glycolytic efforts is improved.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: And that alone, it... And, and, like, you, and if you see, if you... As an athlete, as a, as a sh- as a meathead, as a strength person, you see, like, this dramatic decay in your ability to sustain, like, rep counts and-
Dr Mike T Nelson: Yep ...
Dr Nathan Jenkins: you know, a- a- and perform under fatigue, um, that alone should be justification to, like, "Okay, maybe I should pay attention to cardio a little bit," you know?
Um-
Dr Mike T Nelson: Yeah, and that's more my sell because-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: yes, some people will be doing it for health-wise, of course.
Dr Nathan Jenkins: Mm-hmm.
Dr Mike T Nelson: The reality is most people will do it because of performance. Mm-hmm. And if I can get people to do it because of performance, they're still doing it, so cool. I'm happy with that. You- you're still getting better than what you, what you were before.
Dr Nathan Jenkins: Thank you. That's right. That's right. That's right. Yeah. Yeah, there's a myriad reasons. [00:39:00] Perform- like, and I can't think... There's, but the, the cool thing is there's not really a downside. You know, performance- No ... if that's your goal. Health, if that's your goal. Uh, the health is the, for me, also the main, the main driver, but it turns out, turns out the more, um...
This is a mess. I don't know how much, uh, of your audience is, like, a, uh, the, the CrossFit, uh, cult, I mean, enthusiast, uh, crowd. Yeah. But- We got a fair amount of hybrid-type people here ... I, I, I can say that as, as a card-carrying member of- Yeah, yeah ... to train CrossFit six days a week for the last 11 or 12 years.
Um, the, uh, the more that I've worked on my aerobic base for that, like through running outside of CrossFit in particular, and, and some degree of rowing, and I've, have a, I have also a big cycling background that I've-
Dr Mike T Nelson: Oh, nice ...
Dr Nathan Jenkins: yeah, like, gotten back into here in the last few years when I, when I can, when I have time.
Um, yeah, the more I've kind of, like, doubled down on the aerobic, my aerobic capacity, the better, turns out, the better I handle, like, crushing metcons with, like- Yeah ... repeated sprint interval, like, g- like f- [00:40:00] you get to the right to the brink of death, and then you come back, and then you get to the brink of death and come back.
Um, whereas, like, early on in that training, that way, like, I'd be, you know, five or six-round workout, I'd be, like, fighting for my life after three rounds, and just in survival mode for the rest of it. Whereas now, it's like- The, I always talk about this with... And if, and if any of my friends and people who are close to me listen to this, as, as inevitably like five or six of them will-
I'm always, I'm always, always, always like, I'm so big on like, "Hey, look, it's not about the first round, it's the last round," you know? Mm-hmm. That's where the quality, uh, of the workout comes in. And so I approach every workout thinking about that, that it's not how you, like, it's not how you start, it's how you finish, you know?
It's like all about that buildup, uh, to the, the sprint finish, if you will. And I think that's, that's something that I view as like a maturity of a, of a, of an athlete like that, and also an appreciation for the, the aerobic- component to it all, which is neglected in the meathead community. It's definitely neglected in the CrossFit community.
[00:41:00] Everybody hates running. Um- Oh, yeah. I mean, Chris Hinshaw- Chris hates, so- ... and people like that made his whole- Yeah ... career out
Dr Mike T Nelson: of just telling people to do more aerobic
Dr Nathan Jenkins: stuff. Yeah, I've never, I've never, I've never met Chris. I've done- I've, uh, followed his work for a while, and it's... Yeah, it's been absolutely revolutionary for the CrossFit world.
But especially for those high-level competitors who have, you know, followed his methods. Um, and it's just, and it's honestly, it's nothing, like I have to note, and this is, like, all credit to him for packaging it and applying it to that audience- Oh, for sure ... when, when they needed it. But it goes back to, like, some very basic ex-fit stuff from, like, 40, 50 years ago.
Um, like, how to, how to train and control your repeated efforts, you know? Uh, like, it draws a lot from, like, the S- the Swedes, who- Yep ... who pioneered that stuff in the '60s. It's really cool. It's really cool to see it, like, go, go on a bit more mainstream, so.
Dr Mike T Nelson: Yeah, and that was, like, the CrossFit ath- and I work with some CrossFit athletes now, but not as many as back in the day.
Dr Nathan Jenkins: Mm-hmm.
Dr Mike T Nelson: They were great because they, once they were convinced, they would- Yes ... do whatever [00:42:00] you told them to do.
Dr Nathan Jenkins: They'd do
Dr Mike T Nelson: whatever you tell them. Like, convincing them was a little bit hard, so my pitch- Mm-hmm ... up front was, the athlete I typically worked with was, "Oh, let me guess. The shorter MetCons you do good, longer ones you get crushed by everyone else, and you can't figure out why, and you've done everything under the sun."
Like, "Yeah, how'd you know?" And, like, you test- Mm-hmm ... their VO2 max and it's, like, 35, 37. It's-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: it's not bad population-wise, but compared to the people they wanna be, it's horrible.
Dr Nathan Jenkins: Well, yeah. And then meanwhile they might have, like, a 500-pound back squat, and then- Right.
Dr Mike T Nelson: Exactly, yeah ...
Dr Nathan Jenkins: c- coming up on a 300-pound snatch is, uh, for, like, a guy.
Yep. Um, so, like, that, that capacity is way, way, way outpaced and- Way below ... uh, uh, well, yeah. So, like, their strength, like, in that s- short, every, like, high power and then short sprint domains, they're great. Yep. And then you, you expand the time domain and they're like a fish out of water. Um-
Dr Mike T Nelson: Yeah. But the crazy thing was- Yes
it would only take six to eight months to see, like, a huge [00:43:00] difference- Yeah ... if I could get them to stop doing MetCons daily. That was usually- Mm-hmm, mm-hmm ... the thing. And then usually the, the hard part was, "Yep, for a while some people in your local gym will probably be beating you, but I guarantee if you, you stay with this, we'll add more lactate stuff, we'll add more MetCon stuff back.
It only takes-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: three, four, five, six weeks to probably get you back to maximum levels as you were before with a bigger aerobic base." You, you can do pretty good. But it was that-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: that middle row where they're sucking, they're like, "I don't like doing these 5K rows, all this repeated shit. This sucks."
"Making me nasal breathe, all this CO2 tolerance shit." Yeah. But if they stayed with it, they're like, "Oh my God, I'm so glad I did it."
Dr Nathan Jenkins: Yeah. Yep, yep. That's, uh, well that's, that in itself is a, can be a distinguishing factor at the ath- in the elite athletic level, um-
Dr Mike T Nelson: For sure ...
Dr Nathan Jenkins: the, the, the ability to stick with something that, when it sucks, right?
So, um, not everybody's built the same way.
Dr Mike T Nelson: [00:44:00] Yeah. And there's tons of, you know... Like, I followed a lot of the people, I don't even know who's in CrossFit right now as much, but, you know, like Rich Froning had to go back and work on row, or running. You know, there's- Mm-hmm ... multiple stories of, you know, top level- He's a great example
Dr Nathan Jenkins: of that
Dr Mike T Nelson: athletes back in the day who were just getting beat by certain events that were more aerobic, took time off, like, made it a focus to make that a priority, and came back and did- Yeah ... really good.
Dr Nathan Jenkins: Yeah, he's, he's the classic example of that, where, like, he, um, I forget the specific numbers, but if you looked at his- His, the d- the def- the differential between his 400 meter sprint time versus his mile time, like that- Oh, it was crazy
it was a c- like the capacity was complete- so lopsided.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: And then now, like, and then, well then he worked on it, became, looked very competent in the endurance- Yep ... domain, obviously. And then now he's like freaking doing, you know, nine-hour bike races, like the Leadville 100. Yeah. And, and I think he just did, I think he just did a triathlon.
Um- Oh,
Dr Mike T Nelson: really? Oh, shit.
Dr Nathan Jenkins: Yeah. Th- yes, some people [00:45:00] will correct. Like I fo- I follow his stuff, but not to that,
Dr Mike T Nelson: to- Yeah, yeah ...
Dr Nathan Jenkins: intense degree. Like a, like a, like a true, like, I guess like a big fanboy, but I'm a- ... I'm a, I'm a huge fan of his. Oh, yeah. Just 'cause like he's, he's like a good example of, uh, an elite level person, and also been very vocal about it, very transparent on his platforms of like, um, "Yeah, I sucked at this, and then I got really good at it."
You know? Then put, you put in work at it for a long time, then you become like very, very good at it. So-
Dr Mike T Nelson: Yeah ...
Dr Nathan Jenkins: that's, uh, well, gosh, like not to get too philosophical, but that's the kind of stuff that I wanna teach my son, you know? Like-
Dr Mike T Nelson: Oh,
Dr Nathan Jenkins: totally ... like, like when it, when, like it was like specifically when it comes to like sports and, and, and all that.
Like, yeah, you know, find something you're good at and focus on it, but also find the stuff you suck at and, and spend some time there.
Dr Mike T Nelson: Yeah. And I feel like he was the first guy who, and I don't know if he did it intentionally or not, that figured out efficiency under load, right? Yeah. 'Cause you watch the old films of him, like just breathing- Mm-hmm
independently of every load. And it also made it look [00:46:00] like he was gonna lose all the time, and he did pretty good. 'Cause he just almost made it look a little bit too easy compared to- Mm-hmm ... a lot of the other competitors at that time. Um, now I think- Yeah ... that's much more of a principle the top athletes have been doing for quite some time.
But I feel like- Mm-hmm ... he was kind of the first person to either figure that out either consciously or unconsciously at the time.
Dr Nathan Jenkins: Yeah. This is, it is a little bit of a deep cut into the old, uh, like classic, I guess the g- people call it the golden era of CrossFit of like in the competitive stage. Like the, the competitions that were really, really fun to watch, to your point.
Like he would be, he would be like a pretty, pretty like poker face- Yeah ... about like exertion. And he would be like, um, either he would, like do this thing where he would come from behind and win a lot of events.
Dr Mike T Nelson: Mm-hmm.
Dr Nathan Jenkins: Um, and just, just all, and, and to the point, like actually it's, it's totally salient to this conversation.
It was pacing. It was pacing strategy. Yeah. Let everybody go out hot and like, but keep your breathing under control. Keep your [00:47:00] cardiovascular system under control. Uh, find that threshold and maybe just a little bit uncomfortable, but that's, not to- Mm-hmm ... the point where your, your face shows it. Um- And that was, uh, turns out to be a really good strategy, and I, I love that.
Like, it's like kinda sleeper, uh, approach to things. Like, it's, it's being... It's about efficiency, uh, about maintaining good quality movement patterns. And if you look at him and another guy, uh, Matt Fraser is the other great- Sure ... example of this, is, um, every freaking repetition looks exactly the same.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: Um, e- even if they're at, like, max capacity.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: And, uh, and it's, they're able to do that because of they've, because they've developed a really good aerobic base. And then it, it's the other, the other, uh, um, less appreciated, I think, example of this in the sporting world is Tour de France athletes or, or high-level cyclists.
Uh, they are notorious for being absolutely in agony but never letting it show in their faces, you know?
Dr Mike T Nelson: Oh,
Dr Nathan Jenkins: yeah. And, [00:48:00] and, like, it's, it's a whole, it's a whole thing of gamesmanship. And, uh, I freaking love it, 'cause you can't do that unless you've really, really, really put in the work. You get the average person that goes out, like, try to go, like, give me, give me a hard mile, you know?
Dr Mike T Nelson: Mm-hmm.
Dr Nathan Jenkins: Um, and then, and, and try to stay composed in that last 400, 200 meters, you know? You can't- They just pass the average person jogging on the side of the road, who's like, "Ah." Yeah, yeah, it looks... Y- like they're, you know, the body language and the facial expressions are, uh- are, are telling. And, um, yeah, I think, I don't know, I j- this, this is, yeah, this is, uh, nostalgic from a, from a CrossFit fan standpoint, but also applications of physiology abound here.
So yeah,
Dr Mike T Nelson: good stuff. Yeah. Funny side story on that, years ago I was a volunteer for the bike race, the Race Across America.
Dr Nathan Jenkins: Oh, yeah.
Dr Mike T Nelson: So we were on the, the four-person team. I wasn't riding, I was just helping with physiology and a bunch of stuff, which basically translated into the driving and whatever they needed done, right?
You know, and- Mm-hmm ... [00:49:00] making sure that they actually drank fluid and didn't kill themselves and all this stuff.
Dr Nathan Jenkins: Yeah.
Dr Mike T Nelson: Which surprisingly, trying to get them on a scale some of the times was not the easiest thing in the world- Sure ... even though it was very simple. But-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: um, we started in, that that year was California, I think San Diego.
We ended in Atlantic City. Mm-hmm. And it's, for, for context, as you know, it's a race. So you're, you're literally competing against other people the entire time over-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: you know, six to seven days type thing. So we're in the middle of, like, frigging Nebraska somewhere, and one of the guys out riding, um, there's a, there's no drafting is allowed.
So if you decide- Okay ... to pass someone, you have a few seconds to ride up by them and then decide, okay, you either have to pass them or you have to drop back. And so this, our rider's kind of bored and he's like, "Yeah, there's this guy in front of me." He's like, "You know, should, should I pass him?" I'm like, "Ah, what do you think?"
He's like, "Ah, I wanna fuck with him for a while." And we're like, "Okay." So he would come from behind and, like, ride up next to him and look at him, and then he [00:50:00] would, like, drop back again. And you could see- Oh, gosh ... that the rider, I think it was an Aus- Austria guy, was trying to match his, his pace, but he didn't wanna look like it was a, a ton of effort either.
Dr Nathan Jenkins: Fun. Yeah.
Dr Mike T Nelson: Yeah. And so our guy Greg's doing this, like, three or four times, and he's like, "Can I just pass him now?" We're like, "Yeah." So we're in the vehicle going past him as he's passing the other rider, and you see him look at him and smile, and our rider just drops the hammer and just blows past him. Oh,
Dr Nathan Jenkins: geez.
Dr Mike T Nelson: And the look on the Austria guy's face of just utter demolishment- J- just, yeah, just complete ... was amazing to see. 'Cause you could tell- Oh, that's so sad ... he did not wanna be passed. Yeah. And he was doing everything he could to not have it happen, and he just, it, it just wasn't gonna be. And, like, the look on his face was just-
Dr Nathan Jenkins: He's
Dr Mike T Nelson: totally-
utter disappointment.
Dr Nathan Jenkins: Totally demoralized. Yeah. That's, that it makes me... Oh, it's heartbreaking for that guy, but I'm glad for your team. Yeah. Um, that is, um... And, and to think, too, like, yeah, I'm a vaguely fam- RAAM, right? Race Across America.
Dr Mike T Nelson: Yes. [00:51:00]
Dr Nathan Jenkins: Um, y- you know, in the middle, you're, you're literally like, that's the worst possible.
You're in literally the middle of Nebraska.
Dr Mike T Nelson: Yeah, you're
Dr Nathan Jenkins: in the middle of America. In this fucking, like ... Day three
Dr Mike T Nelson: and a half.
Dr Nathan Jenkins: Yeah, and you got, like, another half a week to go, and it's like, okay, yeah, just gotta hang on. Um, no, that, that hurts. I'll stick to my, um, I, I cap out at, like, a 10K road race. Oh, there you go.
Yeah, yeah. May- maybe I could be convinced to do a half-marathon one day. But that, um, yeah, there's multi-day- Oof ... or even, like, ultra-marathon kind of-
Dr Mike T Nelson: Ugh ...
Dr Nathan Jenkins: events. Man, I'm not, I'm not built for that stuff. But yeah, that's- Yeah,
Dr Mike T Nelson: it's a, that's a whole nother world at that point- Mm-hmm, 100% ... of
Dr Nathan Jenkins: just,
Dr Mike T Nelson: I mean, I think, and I probably stole this from Dr.
Eric Cobb, is that high-level aerobic sports endurance, especially as it gets longer, are just so much about pain management. Mm-hmm. Like, yes, you have to be good. Yes, you have to be efficient. Yes, you need a good VO2 [00:52:00] max and high lactate and all this other stuff. Yes, all those things are true. Mm-hmm. By the end of the day, it's just hours upon hours.
Even if you're the best in the world, it's still just painful as hell.
Dr Nathan Jenkins: Yeah. Yeah, it's j- it hurts for everybody.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: And, uh, a quote I've heard is, like, you, it, it never gets easier, but you also, you wouldn't want it to.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: Um, and that's true for, that's, that's true for, like, the top-level athletes we're, like, we're talking about- Yeah
and it's also true for- Uh, literally, like, the, the, the 42-year-old that's with a, with a family and a full-time job just coming off the... You know, trying to get, trying to get back into it, you know? Trying to... But starting from, basically from starting from scratch. Um, that's just always how it's gonna feel, so.
Dr Mike T Nelson: Yeah. I have a client who, one girl in particular, a couple years ago, she's like, "Oh, my 2K, I got 10 seconds better." I'm like, "That's amazing. That's, like, a huge increase." Mm. And it was over three, four months or something. [00:53:00] And she's like- That's
Dr Nathan Jenkins: a 2K row? Yeah.
Dr Mike T Nelson: Yeah. Huge. Yeah. And she's like, "But it sucked just as bad."
Yeah, it's- "Does it ever get any better?" I'm like- Nope ... "Unfortunately, no." That's the point. She's like, "You'll do better in times, but that feeling of how much it sucked?"
Dr Nathan Jenkins: Oh, yeah.
Dr Mike T Nelson: If you're doing an actual RP of a nine and a half or 10, like-
Dr Nathan Jenkins: Sure. Feels the same ...
Dr Mike T Nelson: it, it just will always suck.
Dr Nathan Jenkins: That's what I, I- And it's
Dr Mike T Nelson: like, "No."
Dr Nathan Jenkins: The, the, the way I would teach that in the university when I was teaching on VO2 max, like, and gearing the kids up, the students, shouldn't call them kids, the students up- ... to do their own, everybody would do a VO2 max test- Yep ... in the exercise physiology lab.
Dr Mike T Nelson: That's great.
Dr Nathan Jenkins: Um, I shared, like, just my own personal stories.
My VO2 max that I, when I've tested it has ranged at various times from, like, the, the high 30s to the mid-60s.
Dr Mike T Nelson: Wow.
Dr Nathan Jenkins: Um- That's a big range ... that is, it is a huge range. Yeah, that- ... that, okay, mid, I, I'll give you this, too. Mid-60s was, um, when I was in college racing bikes.
Dr Mike T Nelson: Oh,
Dr Nathan Jenkins: okay. Um, like 60, 63, 64. Nice. That was, like, the highest I ever saw.
Yeah, I was pretty, you know... [00:54:00] That was, that was exciting and cool. That was, but that was brief. So then- ... that was 20, that's, we're talking about 22-year-old Nathan here. And then the high 30s was, uh, when I was in a, I was doing my postdoc. Yeah. Uh, after, after six years of neglecting my body and fitness, uh, I got fairly well deconditioned.
Um, and then- Yeah. It's ironic, a
Dr Mike T Nelson: PhD or postdoc's the worst thing to do for your health, actually, in exercise physiology.
Dr Nathan Jenkins: Abs- 1000%, I, I always would tell, like, I tell, like, I would consider myself an exercise philosopher in those days.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: Um, did, subjected many people and also rodents to multiple types and, uh, permutations of exercise, various forms of torture.
But very, did, and, and I certainly studied a lot, wrote a lot, did, graphed a ton of data on it, but didn't do as much of it as I should have. So that was when my VO2 max was that low. I qualified for the, for one of my, uh, PhD classmates, co- you know, uh, colleagues, there, there was a study of trained and untrained, uh, athletes.
Mm. Or trained and untrained [00:55:00] subjects, like two, two different groups, and I, um, I qualified for the untrained group. But rewind four years earlier for my own study, for my own PhD experiment, I was, I was fit enough to be in the trained group at that time. Mm. Completely different. So, like, that was the course of my graduate training-
that, that, that evolution. Um, anyway, these days I hover, according to my Garmin anyway, in the, in the low 50s, so whatever. Um- Yeah, that's good ... so, so, um- I've, I've, to the point I've, I've experienced, I've, I've had this whole spectrum of VO2 maxes, and every single time I go to max effort, it feels exactly the same.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: Um, it feels absolutely the same.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: And that's true for everybody. There is something
Dr Mike T Nelson: to training for it that I have noticed that... And I don't know if it's an expectation or just, like so right now, like in all honesty, eh, my rowing pace isn't really that bad. You know, if you gave me six to eight weeks, I could probably be back to what my peak was.
So it's not- Mm ... super far off. It's not my number one priority.
Dr Nathan Jenkins: Sure.
Dr Mike T Nelson: But I also know because I've been gone and haven't done a lot of interval work- Mm ... that my [00:56:00] ability to handle the sucky factor is at an all-time low. Oh, yeah. There's something about just even if it's not a physiologic thing, just getting that practice in again of remembering- Mm
how much it sucks, like a skill set of being able to work through it, seeing the whole world disappear into, you know, a little- Yeah ... wattage output on a screen. Yeah. There is something where that seems to go away when you haven't done it for a while.
Dr Nathan Jenkins: Yeah, 100%. It's definitely an acquired- It's hard to explain
skill. It is hard to explain. And, um, I could tell you that like as somebody who's been obsessed with that kind of thing, like to a, to a, to, to a pr- potentially a pathological state- ... that I'm gonna take. I'll, I'll choose this pathology over others. How about that?
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: Yeah. Um, that is, it absolut- I 100% agree it's a skill set, and it is, um, the differentiator between like, okay, for me it's like, did I...
If I do that well, is this was a good workout versus not a great workout? Um, [00:57:00] which, and it's, for me, it's all about the recovery in between the pieces, in between the sets- Yep ... or whatever. It's like that, like I just finished the last... I do a lot of, I do a lot of, one of my, for my running training, and you'll appreciate this, I do a lot of work in the- 400 to 800 meter range.
I do a lot of 600 meter repeats, which is- Oh, God ... incredibly- That's horrible ... incredibly uncomfortable. So roughly that, that three-minute time domain, give or take. Yep. Like, for me, like, I'm hovering around 240, 245 for 600 meter repeats, and each one, th- those last 30 seconds is... I mean, it's miserable. It's like- It's horrible.
But then it's like, I, I, I'm a big fan of roughly two to one work to rest, or one to one- Okay ... if I wanna preserve quality. Somewhere, somewhere, like, and, and I change that up, but the, the focus of those rest periods is just getting ready for that next piece. And I do, I do think we're talking a lot about the physiology here, but there's a lot going on between the ears.
Um- Oh,
Dr Mike T Nelson: yeah ...
Dr Nathan Jenkins: and I, I don't, I don't know the, the, the, the, the neuroscience of it all. I'm sure that's very, been pretty well worked out, but, [00:58:00] like, the, the neuronal connections that form as a re- as a result of these repeat efforts, um, and, and subjecting yourself to this kind of metabolic stress repeatedly over time, uh, there's gotta be something to it.
Like, um, like you s- it's a, it is something that is just as important as, I guess, the mitochondrial adaptations and the cardiovascular adaptations, the capillary networks that form. Like, whatever's going on in the, in the brain to help you be able to better deal with this stuff is, is huge. And man, not to get, again, not to get too philosophical, but I personally think it has ripple effects on, like, a lot of other things in life.
Um-
Dr Mike T Nelson: Oh,
Dr Nathan Jenkins: yeah ... just, like, stress management and mood and all that good stuff. It's a, it's a big deal.
Dr Mike T Nelson: Yeah. The one little thing I tell myself, or at least I try to have my clients do too, is that- I have the optionality and a life that's so easy, I have to pick things that are hard. Mm-hmm. And I choose to do them on purpose- On purpose
because I will be better. Yeah. And therefore- I love that
Dr Nathan Jenkins: message, man. [00:59:00] Yeah.
Dr Mike T Nelson: Yeah ... I chose to do this. Like, no one forced me to do it, so if I wanna- Mm-hmm ... be mad at anyone, it's myself. And-
Dr Nathan Jenkins: Yeah ...
Dr Mike T Nelson: and sometimes you have to remind yourself. Even, like, I think cold water immersion's great for this too. Like, I did one yesterday morning.
Yeah. Mm-hmm. Haven't done it for a while. 46 degrees felt horrendously bad. Oof. Like, and I was doing like- Bro, that's so bad ... 30, even 40 before I left. Were you...
Dr Nathan Jenkins: Oh my gosh, really? Okay. Wow.
Dr Mike T Nelson: And yeah, I had to remind myself of like, "Oh yeah, I'm, I'm choosing to do this because it, it is a stressful thing, but I will be better because of it."
Absolutely. And I think there is, and I would love to do a study that the only difference in the study would be one group gets to told, gets air quote forced, you know, IRB approval and ethics. We're not violating- Yeah ... anything there, that they have to do this heinous repeats or cold water immersion or something that they, they hate.
Mm-hmm. And the other group either kind of wants to do it or is informed that they get educational materials. "Hey, look at how this [01:00:00] pre-conditioning really helps your cardiac system. Look at how much exercise helps this group of rats. Look at how much it helped this group of humans. You are opting to do things that are better for your body."
And this goes all the way- Mm-hmm ... back into the, you know, studies they've looked at with insulin response to, I think it was like an ice cream or the, was it the housekeeper study where they told one group- Mm-hmm ... where, you know, you're exercising during the day when you're doing your work, and they see they burned way more, many calories.
And-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: I just think there's something profound to the, the framework or the mindset you go into choosing to do these things.
Dr Nathan Jenkins: Absolutely, man. That's fascinating. Yeah, it basically, it's like the belief effect, um- Of course, yeah. It's a placebo ... the beli- the buy-in effect. It's a, it's a placebo of sorts.
But I think it's a little beyond
Dr Mike T Nelson: that.
Dr Nathan Jenkins: Yeah. So the placebo would be, um... How did, how would you do that, like? You don't know. Yeah, the placebo would be... It's more than, it's more than a placebo. Right. I can't quite articulate how. Um- Like, okay, so, uh, one, one thing I've seen is like a design where, um, [01:01:00] uh, with ca- like this goes back to caffeine restriction.
Well, now we're off on a very much a tangent. That's all right. But to get at the true placebo effect with caffeine, it's like people... So there's the, the classic design is, uh, you give caffeine for like, say, ergogenic aid type study. You either give the placebo or the drug, right? Well, then the other layer that I've seen in some studies is very elegant, is the, what kind of to your point is the, the subjects will be given a, uh...
They will be told like, "Okay, caffeine has these potential beneficial effects." Mm-hmm. And they- they- there also sometimes will be deceptions like you have received this caffeine- Yep ... actually, and, and, and, and in some cases they've received... The, if you, you're told you, you've received this caffeine, here's the benefits you should expect.
And in they, even when they have actually been given the placebo, but they've been told the beliefs, they see some of the same benefits that you would see- Yep ... with caffeine. Um, so that's like the, that's the placebo belief effect. [01:02:00] When the subjects have been told th- that they have not received caffeine, but they actually have And, and they're also knowing the benefits, then they don't get the same benefits, right?
So like-
Dr Mike T Nelson: Mm-hmm ...
Dr Nathan Jenkins: that's like the belief, the factor coming in is like, "I don't believe I've received it, so I'm not gonna..." So then whatever. But they actually did receive the drug, right? Yeah. So, uh, but they didn't see much effect on, like, perceived exertion, which is one of the classic effects of caffeine. So it's really, there's something to, like, the, the psychology of it all, and I bet there's something to it in the context that you're talking about is, like, if I choose to induce this kind of like w- this sort of stress on my system, the, to, to tie it back to the things we've been talking about, like whether it's metabolic stress in the form of hard interval training or cold water immersion, which, bro, that is crazy.
You're talking about 46 degrees, 45 degrees. So at the, at the, where I, where I train, it's a, uh... Uh, well, there's a, there's two businesses under one roof. There's a training facility, the, the CrossFit gym, and then upstairs is a [01:03:00] recovery s- facility.
Dr Mike T Nelson: Oh, nice.
Dr Nathan Jenkins: And there's, there's two... There's a bunch of different stuff in there.
Uh, but there's two cold water immersion tanks, two plunge, plunge, uh, cold plunges. One is 45 degrees, one is 55 degrees, and I have not graduated to the 45-degree tank yet. The 55 is all I can ha- Like I'm a, I'm a wimp about this stuff. Um, and I have a, I have a- You
Dr Mike T Nelson: also
Dr Nathan Jenkins: live
Dr Mike T Nelson: where it's hot ...
Dr Nathan Jenkins: I do live where it's hot.
So the 55 does, does feel quite good. Yeah, I'm in, I'm in Georgia for the... I don't know if I mentioned that at the beginning. Yeah. But yeah, I'm just outside of Atlanta,
Dr Mike T Nelson: Georgia. If I'm in the heat, it takes me a good four weeks to heat acclimate. Like, I'm pretty good in Minnesota in-
Dr Nathan Jenkins: Mm ...
Dr Mike T Nelson: July and August 'cause I train- Yeah
in the garage and most of the time, and it- Ugh ... it gets hot here.
Dr Nathan Jenkins: Yeah, yep,
Dr Mike T Nelson: yep. Um, but, like, the first two weeks of where it gets really hot, I'm like, "Ugh, this sucks."
Dr Nathan Jenkins: Yeah, it's... We're in it now, man. Well, actually, we got some beautiful days right now here. We're in May. Um, but we've had some, we've had some warm days, like approaching, I think we've hit 90 once or twice already.
Dr Mike T Nelson: Oh, yeah.
Dr Nathan Jenkins: Um, and then this weekend I have a, my next, my next ra- I have a [01:04:00]10K on Saturday, and it's supposed to hit- Oh, fun. Yeah, it's, uh, so hopefully... It, it's in the morning, so it won't be too bad, but it do- that day the high is 91 or 92, which is gonna be really hot. So it'll be warm. It's 7:00, 7:30 by the time my, you know, when I, when I start the race, but- Oh,
Dr Mike T Nelson: there you go
Dr Nathan Jenkins: a little, little anxious about that 'cause... But whatever. Yeah. Yeah,
Dr Mike T Nelson: you'll
Dr Nathan Jenkins: do all right. It's high, just, it's only 10K. Uh, it's only, only f- hopefully just under 50 minutes to
Dr Mike T Nelson: pass. Oh, there you go. Nice.
Dr Nathan Jenkins: Yeah, that's the, that's the goal. That's the goal. Nice.
Dr Mike T Nelson: Um. Cool, and then- So
Dr Nathan Jenkins: anyway ...
Dr Mike T Nelson: as we wrap up here, like two- Sure
quick things. Um- Uh, we'll just spend a couple minutes on this. Your thoughts on, we talked a lot about, about learning about systems and how everything is siloed. Mm. So one of the things I propose, and we talked about this before the podcast is, to me, when I learned about metabolic flexibility, which was starting in 2006- Mm
I had never even heard of the term before, and I thought I was pretty up-to-date on exercise fizz and all that other kind of stuff. And what I realized was, oh, one, from a marketing [01:05:00] standpoint, I can give people the term, "I'm looking at metabolic flexibility," and it allows me to talk about everything from carbohydrates to fat use to ketones to whatever.
Mm. But I could give them one term, like the elevator speech- Mm ... of what I'm into. Mm. And then two, I realized, oh, it's a really good lens to teach physiology, period. And it's even a good lens- Yeah ... to teach pathologies, because most pathologies, at least in metabolism, end up being, "Oh, you just became more metabolically inflexible."
Inflexible. "You went the wrong direction."
Dr Nathan Jenkins: Yeah.
Dr Mike T Nelson: What are your thoughts about that as a, like, an overarching kind of framework
Dr Nathan Jenkins: for that to be? 100%. And, uh, yeah, man, that's really the, um, to the extent that metabolic flexibility comes up or presents itself as I, I see the opportunities presented to, to teach it in the medical school setting, that is exactly the, the, the approach that has been kind of swirling in my mind to take on it, is, uh, basically this unifying conceptual framework to [01:06:00] connect a bunch of things that are traditionally siloed conceptually.
So things like, for example, the biochemistry, the metabolic pathways. You got your, uh, phosphocreatine system, your glycolytic system, your oxidative system. Um, well, turns out the degree to which we can switch between those in states of different metabolic demand, that is metabolic flexibility, right? Um, and so that's like the, the biochemistry and physiology standpoint, but then there's also, like in the medical school, things are taught, um, kind of like d- disease specific, uh, uh, c- content.
So things like you'll see type 2 diabetes, i- insulin resistance. Uh, you'll see fatty liver and metabolic syndrome, and yeah. There, there, I'm sure that there's discussion of ways that those are all interrelated. But again, metabolic flexibility or, or inflexibility is kind of a unifying framework to connect all of it.
Um, and then introduce as well, like, basic exercise physiology, transition from a resting state to a highly metabolically [01:07:00] active state where there's a lot of flux through, energy flux through the system. The, uh, the, the, so metafl- metabolic flexibility, i.e., the ability to, um, switch between energy systems in the f- face of changing metabolic rate and metabolic demand, uh, really unifies a lot of those concepts for me, and it, um, pedagogically, I...
it's very attractive to me, which is to say from a t- uh, a teaching effectiveness standpoint, it's very attractive to me because it, it addresses something that, um, a- again, historically in my, in my experience with undergraduate students in exercise physiology, who, by the way, are mostly going to be medical practitioners of some kind.
In my, in my case, it was mostly physical therapists, but this kind of, like, integrated thinking is very important for them. But in the medical school context, it's even more so, I would argue, because their job, their future job as, as clinicians is going to be to c- make connections, connect the, the dots [01:08:00] between the, um, the basic science and clinical applications, and I really think that metabolic flexibility is a great example.
In fact, in my talk, uh, i- in my interview, I, I don't know if I used metabolic flexibility per se, but here's, here's, uh, here... just, like, really quickly, and then I'll s- shut up. No, no. But the, uh, the, um, the, the essence of that talk was, like, understanding in the, in a ca- uh, basically it was a case study of somebody with Type 2 diabetes and then taking a look at, like, the AMPK signaling pathway-
Dr Mike T Nelson: Oh,
Dr Nathan Jenkins: cool
in that context- Yeah, yeah ... from a pathological standpoint of, okay, the, uh, the problem is with insulin resistance, you know, downregulation of the insulin receptor in the face of ex- um, excessive exogenous or excessive s- endogenous, uh, circulating insulin. Um, we're seeing a lack of signal to that pathway, and therefore lack of glucose transport from the circulation into the tissue, et cetera, et cetera.
So there's a, a glycogen storage problem, and there- therefore hyp- hyperglycemia Well, okay. It turns out that... So [01:09:00] that's a problem with metabolic inflexibility essentially, right? There's an excess energy supply in relation to demand on the system. Well, it turns out that if we look at the, some of our basic, I call it basic exercise physiology, you get contractile activity of that muscle tissue, stimulate that AMPK, um, metabolic pathway, and in completely independent of the insulin signaling, we can stimulate that GLUT4 translocation and glucose uptake.
Um, and then, and then in the talk I also integrated things like drug treatments, like metformin, uh, and how that might impact that pathway and all that kind of stuff. And anyway, it lends itself to this very, very integrative physiological and pathophysiological discussion. And, um, I think the, the, the, the, the deeper we can, uh, en- encourage our students to appreciate the integration between these things more so than simply just the rote memorization of the pathways involved, which is where they kind of...
students tend to settle.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: The medical students, they're smart enough, [01:10:00] you just lock them in a text... in a, in a classroom with a bunch of textbooks, they're gonna figure out how to get the, the, the answers right on the exams.
Dr Mike T Nelson: Oh, yeah.
Dr Nathan Jenkins: The multiple choice exams especially. They will memorize their way- Yep
through it and crush it way better than I could. I was terrible at that stuff. No, I was horrible at that stuff. But I, but it's the, it's the connections between things and the relationships between systems and g- g- understanding the ba- how we can get the basic science to apply to a clinical context or a Where your audience probably more so like a athletic context or, you know, coaching context, whatever.
You know, it all... That's, that's, that is the unlock to a deeper understanding that makes us all, you know, better at whatever the professional capacity is. So, so yes, there's a very frequently... A- as you, as you've noticed, Mike, I give long answers sometimes.
Dr Mike T Nelson: No,
Dr Nathan Jenkins: it's good. Uh, but, but the, uh... Yeah, the, it's a long answer to your question is, yeah, what's my thought on, um, that framework as, uh, that, that metabolic flexibility offers.
It's a really good one.
Dr Mike T Nelson: Yeah, and then the good part is whether it's you're looking at performance or [01:11:00] you're teaching clinicians, is you can drop like very basic blood work on top of that we've had for years. Mm-hmm. Like what's their blood glucose? What's their A1C? Maybe you look at C peptide. Mm-hmm. You...
So we got like the glucose end of the spectrum, and then you've got what are your triglycerides? Like- Absolutely ... your insulin levels. Like what we can now look with just basic blood work and try to have an idea of, oh, wow, you're really F because your blood glucose- Yeah ... is high, your insulin is high. Oh, shit.
Sure. Now your triglycerides are high too.
Dr Nathan Jenkins: Triglycerides are high, yeah.
Dr Mike T Nelson: Uh oh. Your- Yeah ... you cannot use fatty acids either. Even though- Mm-hmm ... type 2 diabetics is classically a carbohydrate disease, which yes, you've got issues on that end. So you got-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: crushed from both ends- Yes ... of the metabolic spectrum, and you're in a world of hurt.
Dr Nathan Jenkins: That's right. Yeah. In that, in that setting, like there's obviously some mitochondrial deficiency- For sure ... like mitochondrial capacity. And so but like the, the cool thing is when you know that stuff, like, okay, how... Th- then the next step is, okay, is this addressable? Yes. Um, [01:12:00] and it's so how? Well, basically increased metabolic flux through the system, work out, right?
Yep. And then, and of course, there's the nutritional component too. Like it's, it's a... The problem is it's a, it's a supply and demand, uh, m- mismatch. Uh, that's metabolic inflexibility is a problem with excess supply relative to demand on the system.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: And so you just- And then where are you gonna
Dr Mike T Nelson: put that excess?
Dr Nathan Jenkins: That's right. Yeah. And it's unfort- a lot of times it's the adipose tissue and which drives- Yep ... the, the, the pathology, you know, uh, in, in multiple, in multiples and ways and there's a whole sequelae there, so-
Dr Mike T Nelson: Yeah. It reminds me of, there's an old rat study I read years ago, 'cause I started looking at insulin, insulin resistance and stuff, and I was like, "Ah, from a body comp standpoint, what if we just made the fat cells more insulin resistant?
Like, would you just prevent fat from going into them?" And I finally found a rat study where they did a knockout study where they, they did just that, and the rats all died early from fatty [01:13:00] liver disease. 'Cause where did the fat go?
Dr Nathan Jenkins: Yeah, it- It
Dr Mike T Nelson: backed up into the liver and
Dr Nathan Jenkins: killed them. Into the liver. Yeah, yeah, fatty liver and probably ectopic deposition on muscle.
Oh, I'm
Dr Mike T Nelson: sure they did too. Uh-
Dr Nathan Jenkins: I'm sure the muscle inside was a mess ... brain, brain was probably... I've, I don't, uh, it probably wasn't that exact same study, but I've seen some data of, like, essentially, like there's these, like, uh, lipodystrophy models- Yes, yeah ... and, and, and genetic conditions where basically the animal, or if...
It, it's actually a human genetic disease- Yep ... as well, where, uh, they basically cannot accumulate adipose tissue. Correct. And they're extremely lean Um, and, and bas- kind of a bizar- it's a bizarre physical phenotype, uh, that- Yeah ... this lean... It doesn't, it doesn't look as good as- It looks weird, to say the least It looks weird.
Yeah. To, to listeners, you don't want this. Um- No. You don't want this version of leanness. It's, like, sub 5% body fat, and it's incredibly dangerous. They usually die of cardiovascular or meta- some sort of metabolic complication of ex- basically excess lipid going to where it shouldn't be. The cholesterol levels in the blood are out of control.
[01:14:00] Sky high. Yeah. It's wild. Um, so yeah, adipose tissue has a, an incredibly important function, which is to store fat where it should be, not... We don't want it to go into liver, we don't want it to go into our coronary arteries, we don't go- want it to go into the ectopic deposits on our muscle, we don't want it to accumulate in our brains.
Um, so yeah, we definitely want it, want it there.
Dr Mike T Nelson: Yeah. My revised thinking is give optionality to substrates to get them out of the bloodstream. Like, probably- Mm-hmm ... putting them into fat tissue is probably a really good thing, like store them in-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: glycogen, store them in other tissues. You could argue about, you know, intramuscular triglycerides, which become an issue, especially in non-athletes, et cetera.
Sure. But then the solution is pull, increase the flux to pull fat from those areas- Mm-hmm ... and then run it back through the system. Right. And I think that's where most people are missing. Like, you know, go lift some- Mm-hmm ... weights, do some aerobic stuff. Maybe you can do some fasting, being hypocaloric a little bit.
Dr Nathan Jenkins: Sure.
Dr Mike T Nelson: You know, all those things are [01:15:00] beneficial- Yeah ... to just basically pull more energy through your system just fixes- Mm-hmm ... a lot of stuff.
Dr Nathan Jenkins: Yep. Yeah, the, the two biggest levers are energy output and energy intake, so you can- Yep ... and, but the, and then from the... Here's, as, as mentioned, I was a nutrition coach for a long time, kind of phasing that out now with the new role, but, like, the tendency is to try to c- crank them both to the maximum degree.
Right. Like, okay, so I'm gonna, I'm gonna, I'm gonna do two hours of steady state cardio every day, like uphill walking on the treadmill, and I wanna be on a 1,600 calorie day diet. Like, okay. Yeah. Nope. No, no, let's, let's be a little bit more measured and, like, create, like, a 250 to 500 a day calorie deficit through some combination of more energy expended and reduced- Reduce intake of the fricking, like, my favorite stuff is, like, the potato chips and the-
Dr Mike T Nelson: Mm-hmm
Dr Nathan Jenkins: and all of my son's snacks. Uh, geez. He's got s- I, I, I, I listen, I probably shouldn't put that on him. It's all me. But, you know, there's lots of... When you got a toddler, well, he's not really a toddler, he just turned four, so yeah, he's [01:16:00] a little boy. He's li- he's got his snacks, and I like to eat off of his plate, too, so I gotta be careful.
Dr Mike T Nelson: Yeah. The analogy I use with clients is I call it, uh, rubber band physiology. Mm-hmm. Like, yes, physics still works, but at some point when you pull the rubber band back farther and farther and farther, if you just even let go a little bit, it's gonna wanna snap back to- Yes ... where it was before. 100%. And so just be careful of how much stress you put on the system.
Again, it doesn't mean physics is broken, it just means that there's a cost somewhere for the more- Mm-hmm ... extreme approaches. Extreme.
Dr Nathan Jenkins: 100%.
Dr Mike T Nelson: Absolutely. Yeah. Awesome. Well, last question, um-
Dr Nathan Jenkins: Sure, man ...
Dr Mike T Nelson: if you could pick four things for the person listening here who wants to, you know, generally improve, let's say, body composition, but they're also watching their performance.
Mm-hmm. What, like, would be your... 'Cause you've worked in nutrition coaching. You got a- Mm-hmm ... good depth of y- physiology. What would be kinda like your four things that they, they should look at or at least focus on?
Dr Nathan Jenkins: Gosh, so four things to [01:17:00] support s- kind of simultaneous pursuit of body composition and performance at the same time?
Dr Mike T Nelson: Yeah, they want better body comp as the number one goal, but they don't wanna, like, see their performance, you know, drop through the floor either- Okay ... when they're doing it.
Dr Nathan Jenkins: Oh, gosh, okay. Yeah, this is a good question. Um, I'm gonna, I'm gonna t- do t- two nutritional maneuvers-
Dr Mike T Nelson: Yeah, perfect ...
Dr Nathan Jenkins: a- as two of those four.
One is to maintain adequate protein intake.
Dr Mike T Nelson: Cool.
Dr Nathan Jenkins: Um, even if you're in- What do you consider
Dr Mike T Nelson: adequate? What would you
Dr Nathan Jenkins: go for? Oh, gosh. Yeah, there's a whole range. The standard recommendation of a gram per pound body weight is a- Yeah ... good starting point, but-
Dr Mike T Nelson: Cool ...
Dr Nathan Jenkins: more and, more and more data that comes out shows that you can get a- get away with, uh, quite a bit less than that.
Um- Mm-hmm ... around .7, .8 seems to be- Yep ... sufficient.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: Uh, based on a lot of- That's what I've used,
Dr Mike T Nelson: yeah. But more is
Dr Nathan Jenkins: not
Dr Mike T Nelson: bad- Yeah ... either.
Dr Nathan Jenkins: More is not bad, and if you... I- i- and, like, I personally, I like, I... It, it's a lot of personal preference i- i- is. Yep. Uh, there's room for that, that here. Uh, I like around that or a little bit more, honestly.
Dr Mike T Nelson: Sure.
Dr Nathan Jenkins: Um, but just because I... [01:18:00] And for those of you who do f- uh, follow me on Instagram, you will know that I cook a lot of, of, of food in general, but specifically protein. Specifically, specifically grilled and smoked meats. There you go. Um- Yes. Yeah, so I'm, like, really, like, I, I have a palate for freaking protein for, for, well, for animal protein, and also I've been getting more and more into, like, plant-based proteins lately, just because I, just 'cause I like food.
Yeah, yeah. And I've been exposed to more things. Like, I freaking, I'm a big fan of tofu. Anyway, um- ... that's a whole other tape. So, but yeah, I think you- Smoked tofu
Dr Mike T Nelson: yet?
Dr Nathan Jenkins: I haven't. I ha- uh, I have actually put it on the smoker.
Dr Mike T Nelson: Okay. All right.
Dr Nathan Jenkins: And then, and then, like, do, like, a sear situation on the-
Dr Mike T Nelson: Mm.
Dr Nathan Jenkins: On the s- it's, um...
Yeah, it, uh, it actually is quite good. Like, I did this, like, sriracha glaze smoked tofu- Ooh ... situation. Yeah, yeah. It's, it's, it's- That sounds pretty good, actually. It's, yeah, yeah. Uh, it's freaking solid, man, with some, uh, with some noodles or some rice. Ooh. Highly recommend. Um, which actually, that's a good segue.
So maintain adequate protein intake, for sure. [01:19:00] Uh, but yeah, when you're, when the performance is a goal and you're do- and when I'm gonna s- I'm gonna define performance as something that's, like, in a high-power output sport of some kind. Sure. And you can fill in the blank there, whether that's a per- like, a anything from a purely strength bias to purely aerobic bias.
If it's a high-effort situation, you're gonna be using carbohydrate to support- Yep ... that work. And therefore, as such, your carbohydrate intake also needs to be adequate, which you're gonna ask me to define that like I did for protein, and that's difficult. That's, that's, that's... Well, if you think of these things as, like, knobs that you can turn the dial on, um, carbohydrate is the one where you have kind of the lo- largest play in that dial.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: Um, you can get away with relatively low carbohydrate intake for some kind of demands. But like the, basically the more the volume of the work, the greater the need is. So, um, anywhere from about that gram per pound body weight per day on the low end, I would say. The ve- that's pretty low. To, like, sheesh, um-
Dr Mike T Nelson: What's the [01:20:00] highest CrossFit athlete you've ever had?
I asked Dr. Mike Malloy this when he was on too, so.
Dr Nathan Jenkins: Uh, over 1,000 grams per day.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: Over,
Dr Mike T Nelson: over 200- He had guys, he had women routinely, he said, 4 to 500 at times.
Dr Nathan Jenkins: Yeah, wo- yeah, women would be
Dr Mike T Nelson: in that range. Grams per day.
Dr Nathan Jenkins: Um, so that, that over 1,000 grams per day was, like, peak volume, you know?
Dr Mike T Nelson: Right, right, yeah.
Dr Nathan Jenkins: That's pretty related. Um, very, very, very, very high. Very, very high. Um, 6, 5 to 6, 700 is not uncommon in that
Dr Mike T Nelson: group. Yep, yeah. No, he was having guys routinely at 700.
Dr Nathan Jenkins: Yep. Uh, just, just for me, man, like I'm just a guy, and I just, I'm just a dude. I'm a 40, almost 43-year-old dad. But I do tend to train twice a day.
I'm at 400 grams of carbs per day.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: At, at 160 pounds, 160-pound body weight, and that's, like, very... Like, to maintain my body weight and body composition, um, that's like kinda where I'm at. 350 to 450 is the p- is the flux. Yeah. And so, um, yeah, it's not, like for somebody that's actually a real athlete and [01:21:00] really good, 500, 600 easy, easy-
Dr Mike T Nelson: Mm-hmm
Dr Nathan Jenkins: uh, for, for higher output, so. Okay, so those are two things, protein and carbs. Um- I can't, I can't, uh, omit sleep- Yeah ... uh, from this conversation, and that's, I know that's your area much more so than mine. Um, that's going to be a huge unlock for w- fill in the blank of whatever it is that you wanna get better.
You know, even add... So for, like for me, when I started consciously working on sleep a couple years ago, the net, the, the result was I added 30 to 60 minutes of, of total sleep time as a result of trying to get better at it when I was like historically neglected it really badly. And as a result of that, I've just by t- just by time, like time in bed was a, is a big variable for me too, um, that has added like roughly 30 to 60 minutes, well, 15 to 30 minutes of the quality indices of like both deep and REM [01:22:00]sleep, um, which I track using my Garmin, so I don't know if that's right or wrong.
I've done it Yep. I got a Garmin ...
Dr Mike T Nelson: many in the
Dr Nathan Jenkins: past. I got a, I got a Oura. And Oura. I got
Dr Mike T Nelson: all sorts of other devices
Dr Nathan Jenkins: here. But, but th- like those, those things have helped quite a bit and, and with our, like we've worked with quite a bit of like clients in common through Rapid and, um- Yep. Absolute rest
Dr Mike T Nelson: device.
Dr Nathan Jenkins: Yeah. Yeah. In, in, in other, in any context in which I've like tried to, whether for myself or for clients, try to improve sleep, the ripple effects are, are, are significant Um, so that'd be the number three. And then number four is, you've mentioned a couple times, kind of some blood work stuff.
Dr Mike T Nelson: Mm-hmm.
Dr Nathan Jenkins: Um, I'm a big...
Obviously, that was my, that was my big role at Rapid, was to evaluate clients' biomarkers, blood work, uh, being the main one, but also urine, stool, and saliva. And just, like, to s- to, to, to, to sweep with the broad brushstrokes from the sta- like, the... If we're talking about four things for the average person, um, most people have a [01:23:00] either deficiency or at least an insufficiency in a few different micronutrients.
Dr Mike T Nelson: Mm.
Dr Nathan Jenkins: Um, fr- and, and I c- I can get insights on this from blood work, but I, I would say magnesium is a big one.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: A huge one for people who are training hard trying to maintain their, their performance. Um-
Dr Mike T Nelson: You use an RBC test. Do you think that's useful?
Dr Nathan Jenkins: I do. Yeah, yeah. The magnesium- Okay ... the RBC magnesium is the best one.
Yeah. The, the pl- serum magnesium is almost-
Dr Mike T Nelson: Too,
Dr Nathan Jenkins: too
Dr Mike T Nelson: well-controlled ...
Dr Nathan Jenkins: almost... It's too... Yeah. Our bodies defend serum magnesium too vigorously to get much insight on cellular magnesium status, so yes, RBC magnesium. Um, but I... It's hard to, like... Uh, I would say o- uh, uh, magnesium, omega-3 status, and vitamin D status are- Mm
the ones that I see most, like, insufficient or o- a lot of the times overtly deficient in- Yep ... people who... Of that demographic that you were just specifically asking about.
Dr Mike T Nelson: Yeah, yeah.
Dr Nathan Jenkins: Um, and so, like, even without blood work, if you just, like, [01:24:00] take a multivitamin and a magnesium supplement, like, then that would probably go a long way to improving, particularly, particularly from the standpoint of maintaining performance while in a calorie deficit, because you're probably not getting that, that shit enough from your diet.
In fact, I'm almost... I would bet a million dollars that you're not getting... If you're hearing this, most of you are not getting that stuff enough from your diet. So, um, go ahead and, and bump those things up, you know, get a little help from the supplement side of things. So that, I think that goes a long way.
Dr Mike T Nelson: Yeah. I just got a blood work on a guy yesterday on my desktop, and his vitamin D levels are 18 or something. They're just-
Dr Nathan Jenkins: Yeah. I...
Dr Mike T Nelson: Yeah, I wouldn't doubt it ... really low. Yeah. Is he
Dr Nathan Jenkins: an athlete?
Dr Mike T Nelson: Nah, this person not particularly, but- Okay. Yeah ... I've seen those numbers on athletes in warm and sunny environments, and I couldn't figure it out, and then later realized they're either practicing in the AM and evening because it's so hot- Yep
or they're, they have equipment and basically clothes on- They're covered. Yep ... and [01:25:00] gear when they're outside, so they don't have any direct sunlight exposure.
Dr Nathan Jenkins: It's- Like, "Oh, shit." It's a huge problem. It's a huge problem. Unless you're working out, if you're, unless you're doing the, the, the, you know, the, the stuff that my friends make fun of me for, which is to train...
Like, basically live s- without shirt outside- ... most of the time. Like, I find shirts to be oppressive. So I don't wear them, but like I'm, I put this, I put this collared shirt on for the first time in forever for this podcast. Oh,
Dr Mike T Nelson: nice.
Dr Nathan Jenkins: But like, yeah, like anytime I'm, I'm running, uh, or working in my yard or whatever, um, I'm being exposed to sunlight.
But, like, so I'm pretty... Like, uh, my vitamin D levels turns out are... But they're actually kind of just, they're just normal. And I actually take- No, you can't
Dr Mike T Nelson: OD on vitamin D from the sun
Dr Nathan Jenkins: either- Well, there's, there's- ... which is a cool mechanism ... there's... Yeah. That's right. And also, like, I t- I don't take, I t- it's included in my multivitamin, but I don't take, uh, s- an extra vitamin D supplement.
But my levels are not, like, crazy. They're, like, in the 40s or 50s most of the time.
Dr Mike T Nelson: Yeah. Yeah.
Dr Nathan Jenkins: Which is sufficient.
Dr Mike T Nelson: Dr. Cannell said that, like, 50 to 55 in-
Dr Nathan Jenkins: Uh-huh ...
Dr Mike T Nelson: climates that have sun exposure that are [01:26:00] even near the tropics, like, the, I think he said the highest they've seen is, like, 55 or 60. Like, you don't-
Dr Nathan Jenkins: Yeah.
Dr Mike T Nelson: You have to be taking- You don't hit the hundreds.
Dr Nathan Jenkins: You only get that through pharma- like, super physiologic doses of supplementation. Double medical use. Yeah. Um, but yeah, like, but also the other thing from, from a n- the reason I asked if they're, that person was an athlete is, so yes, so, like, you can, even if you live in a sunny environment, you can block it by clothing, which I see all the time.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: And then two- Being a, uh, uh, somebody with a lot of metabolic flux, like an athletic ind- even recreational athletic, that d- drains these systems, like these stores big time. Yep. Like our micronutrients are depleted relatively readily with high energy expenditure.
Dr Mike T Nelson: Yep.
Dr Nathan Jenkins: And so this, these deficiencies are very common in, in athletes, and I can use that term very broadly to include everyday folks like ourselves, you know?
Um, so it's... That's something that's a really big constraint on a lot of folks' physiology that's kinda like not, uh, [01:27:00] that well understood. Uh, not that well, not as m- not as appreciated as much as I think it could be, so.
Dr Mike T Nelson: Yeah. I lied. Last question. Yeah, okay. Any micronutrient test you think is useful? I mean, I agree with omega-3, RBC, magnesium, you know, 25-hydroxy for vitamin D.
Dr Nathan Jenkins: Mm-hmm.
Dr Mike T Nelson: Maybe zinc, maybe copper. After that- Um- ... I'd, I'd like your opinion. I, I don't know who to trust after that.
Dr Nathan Jenkins: The only, the only one that I've used to good effect that I think you didn't mention that comes to the top of my head is the omega, um, some, some form of omega-3 status, whether that's blood,
Dr Mike T Nelson: um- Yeah, I
Dr Nathan Jenkins: use a blood test-
Dr Mike T Nelson: Like a-
from
Dr Nathan Jenkins: Dr. Doug
Dr Mike T Nelson: Delves- Yeah ... or Beavis. Yeah.
Dr Nathan Jenkins: Yeah. That, yeah. Um- That's super
Dr Mike T Nelson: useful.
Dr Nathan Jenkins: Yeah, and then with our rapid clients it was, uh, like Omega, Omega Check, I think it was called.
Dr Mike T Nelson: Yeah, or
Dr Nathan Jenkins: Omega Quant-
Dr Mike T Nelson: Um- ... is one of them I think too ...
Dr Nathan Jenkins: right, yeah. Um, worth, worth- Um, assessing, but usually the answer is with the both- most of those is, like, you know, we're walking around at suboptimal Omega-3 [01:28:00] status.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: You know. Um, but it is useful to get the index of, like, okay, where do I need to, like... 'Cause there's, like, ratios there- Mm-hmm ... can be important, so, so.
Dr Mike T Nelson: You could be super high in Omega-6 possibly, which I-
Dr Nathan Jenkins: Correct ...
Dr Mike T Nelson: I still see a fair amount. I've been running that test for, God, 11 years now, I think. Right,
Dr Nathan Jenkins: right.
Dr Mike T Nelson: Um, it has gotten better, but I do now see more higher Omega-3, but I also see higher Omega-6 at the same time.
Dr Nathan Jenkins: Mm-hmm. And it depends, too, if somebody's supplementing or not. Yes. Like, you can see the ratios. Like, one of my last readouts for myself was my ratios were a bit off because I've been supplementing a little bit too aggressively.
So, um, back to... I tried to, like, reduce the dose a little bit, but-
Dr Mike T Nelson: Do you think RBC levels of Omega-3 you can get too high? Like, all the researchers I've talked to, they're like-
Dr Nathan Jenkins: Mm-hmm ...
Dr Mike T Nelson: I can't tell you any data directly, but I'm like, "Okay, what are you personally at?" "Eight, nine, 10%."
Dr Nathan Jenkins: Yeah, right.
Dr Mike T Nelson: They're all, like, super high.
Dr Nathan Jenkins: It's, it's hard to... Well, yeah, that 8 to 11 range is what I've used comfortably. And you
Dr Mike T Nelson: can't really get much [01:29:00] above that.
Dr Nathan Jenkins: Yeah, like, I've never seen anything, I've never seen anything above 11.
Dr Mike T Nelson: I haven't either.
Dr Nathan Jenkins: Um,
Dr Mike T Nelson: so maybe- We may have had a guy take tablespoons upon tablespoons of a liquid fish oil for a, we'll say a six to eight week experiment to see if he sprouted gills, and he maxed out-
at 9.5.
Dr Nathan Jenkins: There you go. Yeah, that's, that's... Yeah, it's hard to s- it's hard to get that high, yeah. Um, but that 8, 8% ballpark, um, seems to be pretty much optimal.
Dr Mike T Nelson: Yeah.
Dr Nathan Jenkins: Uh, I don't think I've ever heard of, like, an overdose of, uh, or anything, so it's not something I would worry about.
Dr Mike T Nelson: Yeah, yeah. Yeah. Cool. Awesome.
Thanks. I know you got... Do you, do you still put in some stuff on Instagram? I know you'll be busy teaching all the students and stuff coming up.
Dr Nathan Jenkins: Yeah, you know, my ins- my Instagram is very much like, um... I certainly, I certainly use it. I'm no longer, like, I'm not taking clients, so just because of the new job, I've got a few clients- Yeah
that I'm gonna continue to work with on a one-on-one basis, uh, for the remainder of the year, so I don't, I don't have anything to promote or plug. Um, but if folks can follow me at [01:30:00]drnathanjenkins, um, all one word on Instagram, uh, if they want to, and yeah, I'll post some, you know, educational content there as I, as I feel inspired.
But also in my stories, you'll get a lot of, uh, food, food pics and videos. Barbecue I've seen. Oh, yeah. Oh, yeah. Oh, yeah. If you like, if you like that kind of stuff. And if, also, if you have any, like, if, if somebody's, like, really into that and knows a lot about it, then feel free to, like, you know, send me all your tips and tricks, 'cause I'm always looking to learn.
Um, and then the other thing I share a lot is just goofy videos of me and my son playing. So, um, it's a, it's a, it's an all c- it's a catchall kind of account, so.
Dr Mike T Nelson: Yeah. That's awesome. Awesome. Yeah, man. Well, thank you so much for sharing all your great stuff here. I really appreciate it, and, uh, stoked- Yeah, man
to hear more about how all the teaching and everything goes, and very cool for those students to, to have you teaching all the, the great stuff, which is awesome.
Dr Nathan Jenkins: Awesome, man. Well, thank you so much for having me, and, uh, yeah, hope it was ... something in here was [01:31:00] valuable for your, for your audience. So- Oh ... yeah.
Dr Mike T Nelson: Always
Dr Nathan Jenkins: does. Appreciate the time. Yeah.
Dr Mike T Nelson: Thank you so much. Appreciate it.
Dr Nathan Jenkins: All, all right, man
Dr Mike T Nelson: Thank you so much for listening to the podcast as always. Huge thanks, Dr. Nathan Jenkins, for being on the podcast, sharing all his wonderful knowledge with us. Really, really appreciate it. If you're going to med school down there in Georgia, you'll be very fortunate to have him as an instructor.
And it's always cool to see more exercise physiology being taught to, uh, medicine students, which is an area that definitely usually gets left out. And I understand there's a ton of stuff you have to cover, but I'm biased to understanding exercise physiology does help you in huge amounts of ways for both medicine, performance, body comp, coaching, lots of different overlaps there.
So big thanks to Nathan. Really appreciate chatting with him as always. If you want for more information for myself, go to the newsletter for free, miketnelson.com/newsletter. A ton of great [01:32:00] stuff going out daily on the newsletter. It's completely free to join. A lot of cool stuff that I don't even put in public.
And if you don't like it, you can unsubscribe. No harm, no foul. Also wanna let you know the Flex Diet cert is opening on June 15th, 2026. This cert is designed for primarily performance and body composition, mostly through nutrition. We cover eight interventions from protein, fats, carbs, uh, NEAT, which is non-exercise activity thermogenesis, movement, micronutrition, sleep, and even basic exercise in there.
So eight interventions, and we've got s-- bunch of expert interviews from the likes of Dr. Stu Phillips, Dr. Jose Antonio, Dr. Hunter Waldman, Dr. Dan Pardee, Dr. Peter fishermen, and many others in there actually. So if you want more information on that, hop on to the Insider newsletter is the best [01:33:00] place. It'll be open from June 15th through June 22nd, 2026 for one week only.
Right now, that's the only other scheduled time it'll be open, uh, not scheduled to open again until January of 2027. So any questions on that, uh, hit me up. As always, thank you so much for listening to the podcast. We really, really appreciate it. If you have time to give us a little review, thumbs up, download, subscribe, all those cool things that help us with the old algorithm, uh, really goes a long way.
So thank you so much once again for listening. Really appreciate it. Talk to all of you next week.