In this Huberman Lab Essentials episode, I discuss how to build muscle strength and size (hypertrophy) and cover key training principles to enhance athletic performance and offset age-related muscle decline. I explain how the nervous system drives muscle movement, the key differences between training for hypertrophy or strength, and resistance training protocols to build muscle for performance and healthy aging. Additionally, I discuss tools for assessing recovery and the role of key nutrients—such as creatine and electrolytes—in supporting muscle development and performance. This episode provides actionable, science-backed strategies to enhance movement, preserve strength with age, and boost energy levels. Read the episode show notes at hubermanlab.com. Huberman Lab Essentials are short episodes focused on essential science and protocol takeaways from past full-length Huberman Lab episodes. Watch or listen to the full-length episode at hubermanlab.com. Timestamps 00:00:00 Huberman Lab Essentials; Muscle 00:02:02 Muscle & Nervous System 00:03:24 Sponsors: Eight Sleep & LMNT 00:06:03 Strength & Aging, Henneman's Size Principle, Use Heavy Weights? 00:10:09 3 Stimuli, Muscle Strength vs Muscle Growth (Hypertrophy) 00:12:11 Tool: Resistance Training Protocol, Increase Muscle Strength 00:15:55 Sponsor: AG1 00:17:50 Tool: Advanced Resistance Training & Volume; Speed, Rest 00:21:12 Testing for Recovery, Heart Rate Variability, Grip Strength 00:24:29 Sponsor: Function 00:26:16 Testing for Recovery, Carbon Dioxide Tolerance 00:29:20 Ice Bath Timing; NSAIDs & Exercise 00:30:34 Salt & Electrolytes; Creatine; Leucine Disclaimer & Disclosures Learn more about your ad choices. Visit megaphone.fm/adchoices
Chapter 1: Who is Andrew Huberman and what is this podcast about?
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. This podcast is separate from my teaching and research roles at Stanford.
It is, however, part of my desire and effort to bring zero cost to consumer information about science and science-related tools to the general public. Today, I want to talk about something that is vitally important for not just athletic performance, but for your entire life and indeed for your longevity, and that's muscle.
Chapter 2: How does the nervous system control muscle movement?
And one of the things that's exquisite and fantastic about the human brain is that it can direct all sorts of different kinds of movement, different speeds of movement, movement of different durations, all of that, is governed by the relationship between the nervous system, neurons, and their connections to muscle. So today, as always, we're going to talk a little bit of mechanism.
I'm going to explain how neurons control muscle. We will touch on some nutritional themes and how that relates to muscle in particular, a specific amino acid that if it's available in your bloodstream frequently enough and at sufficient levels can help you build and improve the quality of muscle. We are also going to talk about recovery. That's when muscle grows.
That's when muscle gets more flexible. None of that actually happens during training. It happens after training. Most people, when they hear the word muscle, they just think about strength. But of course, muscles are involved in everything that we do. They are involved in speaking. They're involved in sitting and standing up. They're involved in lifting objects, including ourselves.
They are absolutely essential for maintaining how we breathe. They're absolutely essential for ambulation, for moving and for skills of any kind. So, When we think about muscle, we don't just want to think about muscle, the meat that is muscle, but what controls that muscle. And no surprise, what controls muscle is the nervous system.
The nervous system does that through three main nodes of control. Basically, we have upper motor neurons in our motor cortex, so those are in our skull, and those are involved in deliberate movement. Those upper motor neurons send signals down to my spinal cord, where there are two categories of neurons.
One are the lower motor neurons and those lower motor neurons send little wires that we call axons out to our muscles and cause those muscles to contract. They do that by dumping chemicals onto the muscle. In fact, the chemical is acetylcholine. Now there's another category of neurons in the spinal cord called central pattern generators or CPGs. And those are involved in rhythmic movements.
Anytime we're walking or doing something where we don't have to think about it to do it deliberately, it's just happening reflexively, that central pattern generators and motor neurons. Anytime we're doing something deliberately, the top-down control, as we call it, from the upper motor neurons comes in and takes control of that system. So it's really simple. You've only got three ingredients.
You've got the upper motor neurons, the lower motor neurons, and for rhythmic movements that are reflexive, you've also got the central pattern generators. I'd like to take a quick break and acknowledge our sponsor, Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep tracking capacity.
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Chapter 3: What is the Henneman size principle and do you need heavy weights to build strength?
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Again, that's eightsleep.com slash Huberman to save up to $350 off your Pod 4 Ultra. Today's episode is also brought to us by Element. Element is an electrolyte drink that has everything you need, but nothing you don't. That means the electrolytes, sodium, magnesium, and potassium, all in the correct ratios, but no sugar. Proper hydration is critical for optimal brain and body function.
Even a slight degree of dehydration can diminish cognitive and physical performance. It's also important that you get adequate electrolytes. The electrolytes, sodium, magnesium, and potassium, are vital for the functioning of all the cells in your body, especially your neurons or your nerve cells.
Drinking element dissolved in water makes it extremely easy to ensure that you're getting adequate hydration and adequate electrolytes. To make sure that I'm getting proper amounts of hydration and electrolytes, I dissolve one packet of Element in about 16 to 32 ounces of water when I wake up in the morning, and I drink that basically first thing in the morning.
I also drink Element dissolved in water during any kind of physical exercise that I'm doing. They have a bunch of different great tasting flavors of Element. They have watermelon, citrus, et cetera. Frankly, I love them all. If you'd like to try Element, you can go to drinkelement.com slash Huberman to claim an Element sample pack with the purchase of any Element drink mix.
Again, that's drinkelement.com slash Huberman to claim a free sample pack. I'd now like to shift our attention to how to use specific aspects of muscular contraction to improve muscle hypertrophy, muscle growth, as well as improving muscle strength. There are a lot of reasons to want to get stronger.
And I should just mention that it's not always the case that getting stronger involves muscles getting bigger. There are ways for muscles to get stronger without getting bigger. However, increasing the size of a muscle almost inevitably increases the strength of that muscle, at least to some degree.
Reasons why most everyone should want to get their muscles stronger is that muscles are generally getting progressively weaker across the lifespan. So when I say getting stronger, it's not necessarily about being able to move
increasing amounts of weight in the gym, but rather to offset some of the normal decline in strength and posture and the ability to generate a large range of movement safely that occurs as we age. So there's an important principle of muscle physiology called the Henneman size principle. And the Henneman size principle essentially says that we recruit what are called motor units
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Chapter 4: What are the key stimuli for muscle growth and strength?
As you recruit more and more of these motor units, these connections between these lower motor neurons and muscle, that's when you start to get changes in the muscle. That's when you open the gate for the potential for the muscles to get stronger and to get larger. And so the way this process works has been
badly misunderstood in the kind of online literature of weight training and bodybuilding, and even in sports physiology, the Henneman size principle is kind of a foundational principle within muscle physiology, but many people have come to interpret it by saying that the way to recruit high threshold motor units, the ones that are hard to get to, is to just use heavy weights.
And that's actually not the case. As we'll talk about, the research supports that weights in a very large range of sort of a percentage of your maximum, anywhere from 30 to 80%. So weights that are not very light, but are moderately light to heavy can cause changes in the connections between nerve and muscle that lead to muscle strength and muscle hypertrophy. Put differently,
Heavy weights can help build muscle and strength, but they are not required. What one has to do is adhere to a certain number of parameters, just a couple of key variables that I'll spell out for you. And if you do that, you can greatly increase muscle hypertrophy, muscle size, and or muscle strength if that's what you want to do.
And you don't necessarily have to use heavy weights in order to do that. Now, I'm sure the power lifters and the people that like to move heavy weights around, will say, no, if you want to get strong, you absolutely have to lift heavy weights.
And that might be true if you want to get very strong, but for most people who are interested in supporting their muscular such that they offset any age-related decline in strength or in increasing hypertrophy and strength to some degree, there really isn't a need to use the heaviest weights possible in order to build strength and muscle.
So there are three major stimuli for changing the way that muscle works and making muscles stronger, larger, or better in some way. And those are stress, tension, and damage. Those three things don't necessarily all have to be present, but stress of some kind has to exist. So this is very reminiscent of neuroplasticity in the brain. There is a good predictor of how well
or how efficient you will be in building the strength and or if you like the size of a given muscle. And it has everything to do with those upper motor neurons that are involved in deliberate control of muscle. You can actually do this test right now. You can just kind of march across your body mentally and see whether or not you can independently contract any or all of your muscles.
Because everything about muscle hypertrophy, about stimulating muscle growth, is about generating isolated contractions, about challenging specific muscles in a very unnatural way. Whereas with strength, it's about using musculature as a system, moving weights, moving resistance, moving the body.
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Chapter 5: How many sets and what weight intensity should you use for muscle strength and hypertrophy?
So you can nest this as a principle for yourself, which is if you want to get stronger, it's really about moving progressively greater loads or increasing the amount of weight that you move. Whereas if you're specifically interested in generating hypertrophy, it's all about trying to generate those really hard, almost painful localized contractions of muscle.
If ever there was an area of practical science that was very confused, very controversial, and almost combative at times, it would be this issue of how best to train. I suppose the only thing that's even more barbed wire of a conversation than that is how best to eat for health. Those seem to be the two most common areas of online battle. What's very clear now from all the literature is that
Once you know roughly your one repetition maximum, the maximum amount of weight that you can perform an exercise with for one repetition in good form, full range of motion, that it's very clear that moving weights or using bands or using body weight, for instance, in the 30 to 80% of one rep maximum, that is going to be the most beneficial range in terms of muscle hypertrophy and strength.
So muscle growth and strength. So let's say you're somebody who's been doing some resistance exercise kind of on and off over the years, and you decide you want to get serious about that for sake of sport or offsetting age-related declines in strength. The range of sets to do in order to improve strength ranges anywhere from two, believe it or not, to 20 per week.
Again, these are sets per week and they don't necessarily all have to be performed in the same weight training session. It appears that five sets per week in this 30% to 80% of the one repetition maximum range is what's required just to maintain your muscles. So think about that. If you're somebody who's kind of averse to resistance training, you are going to lose muscle size and strength.
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Chapter 6: What is the difference between training for muscle strength versus hypertrophy?
Your metabolism will drop. Your posture will get worse. Everything in the context of nerve to muscle connectivity will get worse over time, unless you are generating five sets or more of this 30% to 80% of your one repetition maximum per week, okay? So what this means is for the typical person who hasn't done a lot of weight training, you need to do at least five sets per muscle group.
Now that's just to maintain. And then there's this huge range that goes all the way up to 15 and in some case, 20 sets per week. Now, how many sets you perform is going to depend on the intensity of the work that you perform.
This is where it gets a little bit controversial, but I think nowadays most people agree that 10% of the sets of a given workout or 10% of workouts overall should be of the high intensity sort where one is actually working to muscular failure. But the point being that most of your training, most of your sets, should be not to failure.
And the reason for that is it allows you to do more volume of work. So we can make this simple, perform anywhere from five to 15 sets of resistance exercise per week, and that's per muscle, and that's in this 30 to 80% of what your one repetition maximum.
That seems to be the most scientifically supported way of offsetting any decline in muscle strength, if you're working in the kind of five set range, and in increasing muscle strength when you start to get up into the 10 and 15 set range.
but it's pretty clear that performing this five to 15 sets per week, whether or not it's in one workout or whether that's divided up across multiple workouts is really what's going to be most beneficial. And please do keep in mind Henneman's size principle and the recruitment of motor units.
And remember the better you are at contracting particular muscles and isolating those muscles, the fewer sets likely you need to do in order to get the desired effect. I'd like to take a quick break and acknowledge our sponsor, AG1. AG1 is a vitamin mineral probiotic drink that also contains adaptogens. I started taking AG1 way back in 2012, long before I even knew what a podcast was.
I started taking it and I still take it every single day because it ensures that I meet my quota for daily vitamins and minerals, and it helps make sure that I get enough prebiotics and probiotics to support my gut health.
Over the past 10 years, gut health has emerged as something that we realize is important not only for the health of our digestion, but also for our immune system and for the production of neurotransmitters and neuromodulators, things like dopamine and serotonin. In other words, gut health is critical for proper brain function.
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Chapter 7: What tools and metrics can help assess muscle recovery?
So by taking AG1 daily, I get the vitamins and minerals that I need, along with the probiotics and prebiotics for gut health, and in turn, brain and immune system health, and the adaptogens and critical micronutrients that are essential for all organs and tissues of the body.
So anytime somebody asks me if they were to only take one supplement, what that supplement should be, I always say AG1, because AG1 supports so many different systems in the brain and body that relate to our mental health, physical health, and performance. If you'd like to try AG1, you can go to drinkag1.com slash Huberman.
For this month only, April 2025, AG1 is giving away a free one month supply of omega-3 fish oil, along with a bottle of vitamin D3 plus K2. As I've highlighted before in this podcast, omega-3 fish oil and vitamin D3 plus K2 have been shown to help with everything from mood and brain health to heart health and healthy hormone production and much more.
Again, that's drinkag1.com slash Huberman to get the free one month supply of omega-3 fish oil plus a bottle of vitamin D3 plus K2 with your subscription. What about people who have been training for a while? If you're somebody who's been doing weight training for a while, The data point to the fact that more volume can be beneficial even for muscles that you are very efficient at contracting.
Now, the curve on this, the graph on this begins again at about five sets per week for maintaining a given muscle group and extends all the way out to 25 or 30 sets per week. However, there are,
individuals who for whatever reason can generate so much force they're so good at training muscles that they can generate so much force in just four or six or eight sets that doing this large volume of work is actually going to be counterproductive so everyone needs to figure out for themselves first of all how often you're willing to do resistance exercise of any kind
And then it does appear that somewhere between five and 15 sets per week is going to be the thing that's going to work for most people. Now this is based on a tremendous amount of work that was done by Andy Galpin and colleagues, Brad Schoenfield and colleagues, Mike Roberts.
There's a huge group of people out there doing exercise physiology and a small subset of them that are linking them back to real world protocols that don't just pertain to athletes. So that's mainly what I'm focusing on today. And surely there will be exceptions.
Now, if you are going to divide the sets across the week, you're not going to do all 10 sets, for instance, for a given muscle group in one session, then of course it's imperative that the muscles recover in between sessions. You might ask, well, what about the speeds of movements? This is actually turns out to be a really interesting data set.
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Chapter 8: Which nutrients support muscle development and performance?
And then in a controlled way, moving that as quickly as one can throughout the entire set, and certainly not going to failure because as you approach failure, the inability to move the weight with good form, the weight inevitably slows down. So as you're probably starting to realize you need to customize a resistance practice for your particular needs and goals.
So we've talked about a few principles. The fact that you need to get sufficient volume, you need at least five sets to maintain, and you probably need about 10 sets per muscle group in order to improve muscle. That moving weights of moderate to moderately heavy weight quickly is going to be best for explosiveness.
That isolating muscles and really contracting muscles hard, something that you can test by just when you're outside the training session, seeing whether or not you can cramp the muscle hard will really will tell you your capacity to improve hypertrophy or to engage strength changes in that muscle.
That your ability to contract a muscle hard is inversely related to the number of sets that you should do in order to isolate and stimulate that muscle. Now, how long to recover between sets? This is a question for the testosterone protocol. Duncan French and colleagues found that it was about two minutes, keeping that really on the clock, two minutes, not longer.
For hypertrophy and for strength gains, it does seem that resting anywhere from two minutes or even three or four or even five or six minutes can be beneficial. So how do we know if we've recovered? How can we test recovery? And this is not just recovery from resistance training. This is recovery from running, recovery from swimming.
Up until now, I've been talking about resistance training more or less in a vacuum. I haven't even touched on the fact that many people are running and they're doing resistance training or they're swimming and they're doing resistance training. Well, you can assess systemic recovery, meaning your nervous system.
and your nervous system's ability to generate force, both distributed and isolated, through three main tests. And fortunately, these tests are very simple. And two of them are essentially zero cost, require no equipment. HRV, heart rate variability, has made its way finally into the forefront of exercise physiology and even into the popular discussion.
I've talked about HRV before, how when we exhale, our heart rate slows down because of the way that our diaphragm is connected to our heart and to our brain and the way our brain is connected to our heart. When we inhale, our heart rate speeds up and that is the basis of heart rate variability. Heart rate variability is good. but heart rate variability is difficult for a lot of people to measure.
There are two measures, however, whether or not you recovered that you can use first thing in the morning when you wake up in order to assess how well recovered you are and therefore whether or not you should train your whole system at all that day. The first one is grip strength.
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