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Essentials- How to Exercise for Strength Gains & Hormone Optimization | Dr. Duncan French

Huberman Lab

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  • How Resistance Training Drives Hormones
    • Resistance training triggers both mechanical and metabolic stress that drives hormonal responses like adrenaline and testosterone.
    • Duncan French highlights sympathetic arousal and catecholamines as key mediators of acute anabolic signaling. Transcript: Andrew Huberman Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I’m Andrew Huberman, and I’m a professor of neurobiology and ophthalmology at Stanford School of Medicine. And now, my conversation with Dr. Duncan French. Duncan French, great to see you again. Duncan French Likewise, likewise. Thank you. I don’t often have many Stanford professors in the Performance Institute, so I’m really excited. Andrew Huberman Oh, well, this place is amazing, and you have a huge role in making it what it is. I found dozens of papers on how weight training impacts hormones, and your name’s on all of them. What is it about engaging motor neurons under heavy loads sends a signal to the endocrine system, hey, release testosterone? I’ve never actually been able to find that in a textbook. Yeah. Duncan French I mean, I think it’s a stress response, right? It’s mechanical stress and it’s metabolic stress. And these are, you know, downstream regulation of testosterone release at the gonads comes from many different areas. You know, my work primarily looked at, you know, catecholamines and sympathetic arousal. So things like epinephrine, adrenaline. Correct. Yeah. Epinephrine, adrenaline, (Time 0:00:00)
  • 6x10 At 80% For Anabolic Response
    • Use heavy multi-joint lifts at ~80% 1RM with high volume to increase testosterone, e.g., 6 sets of 10 reps on squats.
    • Adjust load so each set completes ten reps and rest 2–3 minutes to balance intensity and metabolic stress. Transcript: Duncan French Testosterone is really stimulated by an intensity factor and also a volume factor. Now, growth hormone is a little bit different. That’s largely driven by an intensity factor alone. If you look at many of the exercise interventions that we use to try and investigate and interrogate testosterone, it was usually a six by 10 protocol. So six sets of 10 repetitions, which is quite a large, 60 repetitions is quite a large volume for a single exercise. And that was usually pitched at about 80% of a one repetition max intensity. Andrew Huberman Okay. So 80% of the one rep max, six sets of 10 reps separated by rest of- Two minutes. Two minutes, which is actually pretty fast. Yes. At least to me. It is. Anytime you see these two to three minutes, when you’re actually watching the clock, those two minute rest periods go by pretty fast. Duncan French By the third, fourth set, you’re dying for more. Yeah. Yeah. We formulated that kind of exercise protocol to really target you know the release of testosterone and try and drive up these anabolic environments to study the you know the endocrine Um you know consequences but i think that’s that’s that’s the type of protocol that is most advantageous for driving anabolic environments and that was it for the workout? Yeah, we would do that in a back squat. So, you know, multi-joint, you know, challenging exercise, multi-muscle, multi-joint, 80% load of your one repetition max, and then six by 10. (Time 0:04:53)
  • Manipulate Rest To Target Metabolic Stress
    • Shorten rest periods (e.g., 2 min) to increase metabolic stress and hypertrophy stimulus.
    • Extend rest if you must preserve mechanical intensity, since rest length shifts the metabolic environment. Transcript: Andrew Huberman Is there any evidence that training slowly can offset some of the negative effects of doing a lot of volume? Duncan French The rest is often the consideration that’s overlooked out there in general population and in many sporting environments. You know, the rest is as important a programming variable as the load and the intensity, the load, the volume, etc. If you extend the duration of your rest periods, what you’re ultimately doing is influencing that metabolic stimulus again. You’re allowing the flushing of the body, the removal of waste products, you know, lactate to be removed from the body. (Time 0:07:52)
  • Frequency For Intense Anabolic Sessions
    • Do high-intensity testosterone-focused sessions about twice weekly for most people.
    • Fill other sessions with higher-rep volume or lower-intensity work to balance adaptation and recovery. Transcript: Duncan French Yeah. I mean, I think that comes back to your training age and your training history. Obviously, there’s a resilience and a robustness with an incremental training age. So a protocol like that, we would look at two times a week, something that’s pretty intensive like that. Because again, it comes back to the point you make is that you really need to be, for want of better terms, suffering a little bit through that type of protocol, both in terms of the challenge Of the load, but also being able to tolerate the metabolic stress that you’re exposed to. It’s a bit of a sicko feeling, right? Because of the lactate that you’re driving up. So I wouldn’t promote an athlete doing that type of modality multiple, multiple times unless you’re from the realms of bodybuilding. And then you really, that’s the sole purpose of what you’re trying to achieve. If it’s just somebody, you know, a weekend warrior that wants to keep in shape and look good, I would say, you know, two times a week for a really challenging workout like that, and then Flex the other types of workouts within the week to have more of a volume emphasis where you reduce the intensity and you might just look at, you know, larger rep ranges from 12 to 15 to 20. Another workout where you’re looking at, you know, reducing the volume, but increasing the intensity and really trying to drive, you know, different stimulus to give you more end Points of success. Last (Time 0:11:16)
  • Short-Term Stress Can Raise Testosterone
    • Short-term acute stress boosts testosterone via pre-arousal and sympathetic activation.
    • Higher adrenergic responders sustained force output longer during challenging workouts. Transcript: Andrew Huberman Time I was here at the UFC Performance Institute, we had a brief conversation and I want to make sure I got the details right, that in the short term, a big increase in stress hormone can Lead to an increase in testosterone, like a parachute jump. Correct. So stress can promote the release of testosterone. Yeah. That was news to me. Right. We always hear about stress suppressing testosterone, stress suppressing the immune system, all these terrible things. But in the short term, you’re saying it can actually increase the release of testosterone. So I have that right? Correct. Okay. And so then the second question is, does my cognitive interpretation of the stressor make a difference? In other words, if I voluntarily jump out of a plane with a parachute, does it have a different effect on my testosterone than if you shove me out of the plane against my will? Well presumably with a parachute too. Duncan French I mean, so this was what all my PhD work was looking at was the exposure to a stressor and the pre-arousal of how your body essentially prepares for that stressor and then how it manages It throughout the exposure to the stress. We use the resistance training protocol that these athletes knew was going to be very, very challenging. It’s going to be that it’s going to have some anxiety to doing it. They knew there were going to be some physical distress from doing it. And therefore, you know, their mindset of how they were going to approach that was already set. So what we saw prior, 15 minutes prior to the start of an exposure to the workout, the epinephrine, the neuroadrenaline, the adrenaline was already starting to prepare the body sympathetically To go into what it knew was going to be a very, very challenging workout. Andrew Huberman So what was the takeaway there? Is the stress good for performance or is it harmful? Duncan French That’s a great question. From my data, certainly the greater the arousal, the higher the performance was from a physical exertion perspective. There’s definitely an individual biokinetics to some of these hormonal kind of releases. And as much as those guys that had the highest adren response in terms of epinephrine release, norepinephrine release, also sustained force output for a longer period of the workout Than those that didn’t. (Time 0:12:34)
  • Periodize Cold; Avoid Post-Workout Ice Baths
    • Avoid regular cold exposure immediately after hypertrophy sessions, as it can blunt mTOR and growth signaling.
    • Use cold strategically in competition or taper phases when preserving performance matters more than growth. Transcript: Andrew Huberman In particular, things like ice baths, cold showers. In theory, that’s stress also. It’s epinephrine. And so how should one think about the use of cold for recovery? Duncan French You know, throwing your body into, you know, a cold tub, an ice bath or whatever it may be, certainly is going to have a physiological stress response. Now, people are using that for different end goals. And again, I think that’s where the narrative has to be explained. If you are using the stress specifically to manage the mindset, to use it as a specific stress stimulus, that’s the same as me doing 6 by 10, 80%. You know, you’re just trying to find something to disrupt the system, to do something that’s very, if you want a better term, painful, discomfort, whatever. You’re just finding a stressor and then being able to manage the mindset. But if you’re using cold, from a physiological perspective to promote, you know, redistribution of vascularity, of blood flow, you know, to different vascular areas of muscle that You feel have gone through a workout that are damaged or whatever it may be. I think we’ve got to understand what that stress mechanism is. And, you know, the data, the literature is certainly still out there with respect to cryotherapy and cold baths and some of these cold exposures in terms of what they do at the level of The muscle tissue. If that’s the target, if you’re trying to promote a flushing mechanism or you’re trying to promote redistribution of the blood flow, what you’ve got to understand is that cold is going To clamp down every part of the vascular system. And we’ve really got to understand how the muscle would be redistributed to areas of interest. So, you know, I think the stress response is a real thing with respect to cold exposure. But I think the narrative around what are you using the cold for has to precede the conversation. Andrew Huberman And cold, I’ve heard, can actually prevent some of the beneficial effects of training, that it can actually get in the way of muscle growth, et cetera. Duncan French Yeah, there’s some pretty robust data out there now showing that it definitely has an influence on performance variables like strength and power in particular, but absolutely in Terms of muscle hypertrophy. And there’s a big kind of theme in the world of athletic performance right now in terms of periodization of cold exposure as a recovery modality. When do you use cold? Should you be using cold for recovery in periods of high training load when you’re actually pursuing, it might be general preparatory work, we’re actually trying to pursue muscle Growth. Well, that’s usually where you get the most sore. It’s usually where you feel the most fatigued, but it’s probably not the most beneficial approach to use an ice bath in that scenario because you’re dampening, you’re dulling the mTOR Pathway and the hypertrophic signaling pathway. Whereas in a competition phase where actually quality of exercise and quality of execution of skill and technical work has to be maintained, you want to throw the kitchen sink of recovery Capabilities and recovery interventions in that scenario because you now, you know, the muscle building activity should be in the bank. That should have been done in the general preparatory work. And now you’re focusing on technical execution. So you’re absolutely right. (Time 0:15:11)
  • Short High-Quality Sessions For Skill
    • Prioritize short, high-quality practice sessions for skill learning and stop when fatigue degrades form.
    • Preserve movement accuracy so neural patterns and motor learning remain effective. Transcript: Duncan French No, it’s not a volume-driven exercise. It’s a quality-driven exercise. It is about rehearsal of accurate movement, accurate movement mechanics. And as soon as that becomes impacted by fatigue or inaccurate movement, you’re now losing the motor learning. You’re losing the accuracy of the skill. People can call it muscle memory or whatever they want, right? But essentially, you’re grooving neural axons to create movement patterns, and they’re situational throughout sport, right? Whether it’s a Cruyff turn in soccer or a jump shot in basketball or a forehand down the line, you can carve out that particular posture and position and skill, and you can isolate it, And you can drill it again and again and again. Now, as soon as fatigue is influencing that repetition, it’s time to stop. And the best coaches understand that. It’s shorter sessions that are very high quality. And I think the best athletes in my experience are the ones that consciously and cognitively are aware of it at every moment of the training session. (Time 0:24:04)
  • Use Carbs For High-Intensity Work And Learning
    • Fuel high-intensity training and cognitive learning with carbohydrates to support glucose-dependent performance.
    • Treat brain learning and physical high-intensity efforts as similar glucose-demanding tasks. Transcript: Duncan French After physical performance? If you have an amazing coach who is setting up training in a particular way, it’s challenging. There’s a strain related to it. And I’m not talking physical strain. I’m talking figuring things out, you know, figuring out the skill. And I think that can be stressful. Like, you know, if they hit the right technique, you know, that reward center in the brain, that dopamine shot is going to fly up there. And there’s only so many times that we can get that before that becomes dampened. And I think there’s an energetic piece to it. You know, there’s the fueling of the brain. There’s the carbohydrate fueling exercise that actually the strategy around how you fuel for learning and fuel for physical training is actually pretty similar. Glucose. Yeah, it’s glucose. (Time 0:25:32)
  • Periodize Nutrition Around Training Goals
    • Cycle diet: prioritize metabolic efficiency with low carbs most of the time and add carbs around high-intensity sessions.
    • Time carbs pre/during/post sessions while keeping overall diet relatively low-carb to maintain fat oxidation capacity. Transcript: Duncan French Those lower intensities where we should be fueling our metabolism with lipids and fats, clearly the Western diet and the modern-day diet is heavily driven by processed foods and carbohydrates That people become predisposed to utilization of that fuel source above lipid use, fat use, intensities that are very low. So, you know, some of our data with the fighters shows that as well. But I think the challenge for us is that we’re working with a clientele that require high intensity bouts of effort. So, you know, fueling appropriately is very important for that. Now we use tactics here where we essentially have athletes on what you would say kind of is a largely a ketogenic diet, but then we will fuel carbohydrates around training sessions. So we’ll do very timed exposure to carbohydrates. So it’s not post training, post training, immediately pre during and then immediately post and then the rest of their diets, you know, breakfast, lunch and dinner, what would look Like ketogenic type approaches. (Time 0:28:10)