How to assess your fitness across nine key physical adaptations, with Dr Andy Galpin
Andrew Huberman interviews exercise scientist Dr Andy Galpin on how to evaluate and improve all major components of physical fitness.
Summary
Andrew Huberman hosts Dr Andy Galpin, an expert in exercise science, for a comprehensive walkthrough of the nine major physiological adaptations that exercise can produce — from movement skill and strength through to maximum aerobic capacity and long-duration endurance. Dr. Galpin argues that most people focus on only one or two fitness qualities while neglecting others, and that unaddressed weaknesses act as "performance anchors" that limit overall health and longevity. He provides specific, largely cost-free tests for each of the nine adaptations, along with minimum threshold numbers that indicate whether a person is in a zone of physiological concern. The episode is structured as a practical diagnostic guide, giving listeners a complete self-assessment battery they can complete in roughly three days.
Key Takeaways
FULL TRANSCRIPT
Introduction and the goals of exercise
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 for my discussion with Dr Andy Galpin.
Dr Andy Galpin, super excited to have you here. You're such an immense treasure trove of information on physical training and optimizing for specific goals and outcomes. How should I — or anyone else, for that matter — think about their level of fitness in terms of really assessing whether or not I'm as fit as I could be and should be, both for the sake of health and performance?
Dr Andy Galpin: When it comes to exercise, people generally have two major goals in mind. Goal number one is achieving some sort of appearance. This is: I want to be big, or I want to not be too big, or I want to be lean. There is an aesthetic component to almost everybody. They want to look a certain way or not look a certain way. The other one is functionality — I want to be able to perform a certain way. That definition differs per person: I want to be better at strength, I want to be better at mobility, I want to be able to have energy throughout the day, whatever it is. So there's some appeal to aesthetics and some appeal to functionality.
Within both of those categories, we want to be in a position where we can understand where do I need to go with my exercise training so that I can be as fit and as healthy and achieve these goals that I want now, as well as be in a position where I can maintain them for a long period of time. This blends both immediate goals — say you're just interested in squatting a lot of weight, or running your best 5K time — with the desire to have a long wellness span, to be fit throughout life, to achieve all those things for as long as possible.
The question then comes back to: how do I know which area I need to focus on the most, and why am I not achieving these goals, or how can I get there more effectively? If we look at the big picture, we have to understand that there are several major components to physical fitness that are going to be required in all of these categories. What I'd love to do today over the course of our discussion is hit exactly what those concepts are and then cover a whole bunch of different methods for various goals.
The nine physiological adaptations
Andrew Huberman: What are the major adaptations that one can create in their body using exercise?
Dr Andy Galpin: The physiological adaptations can be bucketed into nine areas. The very first one is what I call skill or technique. This could be running more effectively, practicing a skill like shooting a ball or swinging a golf club — anything like that. I call that skill development.
The second one is speed. This is simply moving at a higher velocity or with a better rate of acceleration. That's very similar to the next one, which is power. Power is speed multiplied by force.
The next one, number four, is force or strength. Those are really synonymous terms — how effectively can you move something? This is often confused with muscular endurance. Strength truly is a marker of what's the maximum thing you can move, or what's the maximum amount of force you can produce one time.
Number five is muscle hypertrophy, and this is the first time we're talking about an appearance rather than a functional outcome. This is simply how big is your muscle — that's muscle hypertrophy, or muscle size.
After that is muscular endurance. This is how many repetitions you can typically do of a movement — how many push-ups in a row you can do, how many sit-ups in a minute, things that are typically in the five to fifty repetition range. It is almost always local muscle. A push-up test is really how many reps your triceps, pecs, and deltoids can do. It is not cardiovascular endurance. It is not a global physiological endurance — it's specific to typically one or a few muscle groups at a time. This is why you have to do multiple tests for every group.
After that, number seven, is what I call anaerobic capacity. This is more synonymous with maximum heart rate. Now we're looking at, rather than a single movement or muscle group, a total physiological limitation — the maximum amount of work you can do in say 30 to 45 seconds, maybe even up to 120 seconds of all-out work. Think of your classic interval type of stuff. How much work can you do at a maximum rate where you're going to enter tremendous amounts of global fatigue?
The next one is maximum aerobic capacity. This is probably something in the 8 to 15 minute range where you're going to reach both a maximum heart rate as well as a true VO2 max. That is different from the previous one, where you can't reach this in a matter of seconds — it simply takes multiple minutes to get to a position where your VO2 max is actually going to be sufficiently challenged.
And then the last one, number nine, is what I call long duration. This is just your ability to sustain submaximal work for a long period of time with no breaks, no reductions whatsoever. This is often called steady-state training, or a lot of people just think of this when they think of "cardio." Your ability to continue movement without any breaks or change is the last and final adaptation. If you look at a minimal number, it's generally 20 minutes, but a more typical range would be 20 to 60 minutes. Anything past that would still be limited by your long-duration endurance — your ability to sustain work over time.
Assessing movement skill
Andrew Huberman: Can you walk us through the nine different adaptations and give us a way to assess our level of adaptation in each of those nine?
Dr Andy Galpin: The very first one we want to talk about is movement skill. This is really about human movement so that you stay injury-free and can continue to train for as long as possible. What are the minimum requirements?
If you have access to a highly qualified physical therapist or movement specialist, that's the best route. Go to them, have them identify all of your movement patterns — overhead pressing, squatting, running, all these things. That's your gold standard. If you want to do it yourself, here's a very simple four-step solution.
I teach this joint by joint — the major ones being your shoulder, elbow, low back, hip, knee, and ankle. What you can do is perform a representative movement for you. If you bench a lot, use the bench. If you do pull-ups, use the pull-up. If you squat, do that. I would recommend doing an upper body press, an upper body pull, a lower body press, and a lower body pull. An example would be a push-up, a pull-up or a bent row, a squat, and a deadlift. Record a frontal view and a side view — probably three to ten repetitions per angle, slow and controlled.
You want to look for four key things. Number one is symmetry — front to back, left to right, and your right limb versus your left limb. If they aren't moving perfectly, that's fine, but you want to see: is one moving further ahead than the other? Is one turning to the side and the other isn't? Is one fidgeting and twitching around differently? You want to check and make sure they're stable.
Number two, you want to look for stability. Key indicators are things like: if you can't control a squat, if your knees start shaking during a controlled squat, that would be an instability issue. Can you do the movement slowly? Can you pause at the bottom — maybe three seconds, maybe five or ten? You should have complete control of that movement at all of these joints. Are your hips sliding to one side when you stand up? Is one elbow closer to your body when you're benching and the other one's more flared out? You're simply looking for asymmetries or instabilities.
The third one is what I call awareness. There are a lot of movement technique issues that are simply because people don't know. You'll watch someone squat and when you just tell them, "Hey, did you realize your heels were supposed to be on the ground at all times when you squat?" they say, "Oh, okay," and they can correct it. It's not actually a movement flaw — it was just simply an awareness issue.
And then number four is range of motion through each joint and each movement. During a squat, your knee should be able to go as far over your toe as possible while maintaining good position — feet flat on the floor, three points of contact, not compromising another joint.
Those are the four things: symmetry, stability, awareness, and range of motion. You can generally clear these things in one or two repetitions in a couple of seconds. My scoring system is 0, 1, 3. Zero means you're not going to do this exercise because you're at very high acute risk — you might get hurt on rep one. A score of one means there's a minor flaw; we can probably do it, but we need to be cautious of load and volume. A score of three means maybe it's perfect, maybe it's not, but go ahead and do it on a reasonable protocol — you'll be fine.
Assessing speed and power
Andrew Huberman: What about speed?
Dr Andy Galpin: I actually don't think this is one most people should test. If you're a high-performance athlete, we can run a 40-yard dash or use a velocity transducer on a barbell. For most people, pure speed — maximum velocity or acceleration — is generally not that necessary to test.
Andrew Huberman: What about number three, power, which I believe you told me was speed times force?
Dr Andy Galpin: The accessible version here is a simple broad jump. Stand in a normal position, jump out as far in front of you as you possibly can, and measure the distance between where you started and the back of your heel where it lands. A super basic number to look for is your height. If you're five foot five, you should be able to broad jump five foot five. If you're six foot five, six foot five, and so on. That's going to scale down a little bit — about 15% for females, who simply don't have the same power output in general. So you want to bring that number down a little bit.
That's a very crude number. If you look at a high-performance NFL player who's six feet tall, they're going to be jumping nine to ten to eleven feet. We're not looking for optimization in this particular test — we're looking for red flags. If you can jump your body height, you're going to be just fine.
To clarify: there's no running approach here. You're going to stand still. You can swing and bounce as much as you'd like before you jump. You measure the distance from the tip of your toe — basically stand behind the line — to the furthest point back where you land. Use the furthest point back of your back heel, since your feet won't land symmetrically.
Assessing strength
Andrew Huberman: What about strength?
Dr Andy Galpin: Strength is really important, and you need to measure it in multiple areas. We'll start with grip strength. You can do this in two ways. You can buy a hand-grip dynamometer — these are anywhere between $20 to $100. You're going to squeeze it and I would do your right hand and your left hand. They'll give you a value in kilograms. You want to look for a minimum score of 40 kg, and ideally above 60 would be a really good spot. You want to make sure there's no more than 10% variation between your left and right hand. Your non-dominant hand actually shouldn't be that much weaker in this test — in fact, the non-dominant can often be stronger because the dominant hand is more for movement precision, writing, things like that. If you're male and you're under 40 kg on a hand-grip dynamometer, we're going to need to train that. For females, it's not that much lower — about 35 kg is the cutoff point.
Another option is a dead hang. Hold on to any bar, ideally one thin enough to wrap your whole hand around — any pull-up bar at the gym. In general, we should be able to hang for a minimum of 30 seconds. Thirty to around 50 seconds is my "good, but we could probably get better here" range. If you're cruising above 60 seconds, I'm generally pretty happy. Now, if you are exceptionally large, this doesn't scale perfectly. If you're 240 pounds, even if you're lean, it's just hard to hang and hold 240 pounds. Conversely, if you're 145 pounds, even if you're unhealthy, you're going to be able to hang for a long time. So just use those as rough numbers.
Andrew Huberman: So that's grip strength. What about strength elsewhere in the body?
Dr Andy Galpin: You can do an upper body strength test if you'd like, although it's not technically something we do very often. One I'm generally more interested in is a leg extension test. A barbell back squat is better — that's my jam, that's my life — but it's very technically demanding. You need spotters, you need comfort, a lot goes into it. For the average person, a leg extension test is fairly standardized. You don't have to worry about technique and people can just get into it and go.
What you want to look for there is a couple of standards. A very simple answer is body weight — can you do a leg extension with your body weight? That's a pretty good number to be at. If you go past age 40, every decade that can come down about 10% and you'll still be in a pretty good slot. So if you're 50 years old and you're 170 lbs, if you can do 160, you're in a pretty good spot. Take it down about 10% every decade after 40.
Any of these strength tests don't have to be done to a true one-rep max. You can use what are called repetition conversion equations. Put on a load that you think is close to your maximum and just do it for as many reps as you can. As long as it's under five reps total, you can go online and enter that into any number of calculators and it will tell you your estimated one-rep max. So if you did three repetitions at 200 lbs, your one-rep max is probably 215, whatever. If you get past five repetitions or so, the accuracy of those equations starts going down. Don't put on something, do 12 reps, and then try to figure out your max — the accuracy just gets worse and worse.
If neither of those are an option, another one I like a lot is simply a front squat or a goblet squat hold. You're going to hold a weight in front of your chest — a kettlebell is great, a dumbbell is fine — and you want to hold about half of your body weight. Go all the way to the bottom position and try to hold that for about 45 seconds. It's a pretty good indicator of your position, your core strength, and your low back stability. It's more difficult than the leg extension, but it's quite a bit more functional and it's going to give you insight into a lot more areas than just the quadriceps.
Andrew Huberman: So 45 seconds down at the bottom of the squat, and then returning to a standing position?
Dr Andy Galpin: Yep. And if you can't do the return, I'm actually not that worried — as long as you can hold that good position without a technical breakdown in those 45 seconds, that's a really good spot. As an intro standard, I want a third of your body weight for 30 seconds.
It's important to add a couple of caveats to the strength testing. Number one: these are assuming you are technically proficient. I don't want you to do any exercise to exhaustion or to maximum strength if you're not comfortable with your technique. Adjust accordingly. If you're not comfortable with the front squat, do the leg extension. If you're not even comfortable with that, do something different. We never want to utilize maximum testing if it's going to come with a consequence of serious acute injury.
The second caveat is that your warm-up protocol will have a huge effect on your actual results. Whenever you do these tests, especially if you're going to test again down the line, you want to make sure that warm-up protocol is standardized.
Assessing muscle hypertrophy
Andrew Huberman: What about hypertrophy?
Dr Andy Galpin: The aesthetic portion of hypertrophy is entirely up to you — there's no rationale there. You can decide what looks good or doesn't look good. But there is a sufficient amount you need to have where below that is detrimental to your health regardless of your aesthetic goals.
The best way to assess this is any sort of body composition test. Whether this is a DEXA scan — which is the gold standard — or bioelectrical impedance or other methods, there are a ton of different tests you can get that are pretty close.
What you want to pay attention to when you get a DEXA scan is a number called FFMI — Fat-Free Mass Index. You can look at any number of online calculators; these are all standard, so it doesn't matter where you pull them up. That's going to tell you if you have sufficient muscle mass. A number you want to look for in general: if you're a man, your FFMI should be something like 20 or higher. If you're a woman, you want to look for something like 18. Those are the targets. If you get past 24 or 25 for a man, that's a lot of muscle mass — assuming you're reasonably lean. If your FFMI is 24 or 25 but your body fat is 40%, you're actually just a very large individual and you're not in a great spot. So when we say these numbers, the assumption is that you're probably sub-30% body fat for a man and sub-35% for a woman.
All you really need to know is your total body weight, your body fat percentage, and your height. Enter those three numbers and the calculator will tell you your FFMI score and correct for an adjusted value. Most of those will actually tell you the grading rubric — good, average, bad, etc.
If you are, as a man, sub-17, or as a woman, sub-15, now we're in an area of pretty severe physiological detriment from insufficient muscle.
Assessing muscular endurance
Andrew Huberman: What about muscular endurance? Is this where you're going to tell me I need to do wall sits?
Dr Andy Galpin: You can do any number of tests here. A standard plank — can you hold a front plank for 60 seconds? Can you hold a side plank for 45 seconds? If you're able to do a push-up, for a general male we should have no problem doing 25 or more consecutive push-ups. This would be a full complete lockout of the elbows at the top and a full chest touch — or close to it — at the ground. You can do it differently, but just keep it standard between your pre-test and your post-test if you're trying to mark progress.
Andrew Huberman: And for females?
Dr Andy Galpin: That's going to scale down a little bit. You're looking at 15 as the marker — like 25 was for the male. I want to see above 15. If we do, we're good. Anything between 5 and 15 is the "okay, we could improve" range. If you're sub-5, we generally have some problems. And if that number is between one and zero — zero is a problem.
The other way to assess muscular endurance is to take the exact strength test you did earlier, load it to 75%, and do that for as many repetitions as you can. That is a tremendous barometer of muscular endurance. If you're able to do 200 lbs on your leg extension test, put 75% on that and do as many reps as you can. You want to look for more than eight repetitions. If you are below eight repetitions, then we have a muscular endurance problem.
Assessing anaerobic capacity
Andrew Huberman: What about anaerobic capacity?
Dr Andy Galpin: This one's more challenging. You either have to go to a laboratory and do something like a Wingate test — a 30-second maximal test where you see how much work you can possibly do in that 30 seconds. If you don't have access to a laboratory, you can do this on any protocol you want: sprinting, an air bike, a rower, anything where you can exert maximum effort without having to worry about technical problems. I generally don't like to do things like a kettlebell swing for this — there are just too many other variables. You need to be able to go as hard as you possibly can, knowing you're going to reach a place of tremendous fatigue.
In the lab, we often use what's called a Bosco protocol. You stand on a force plate and do as many vertical jumps as fast and as high as you can for 60 seconds — and you are absolutely destroyed by about second 45. So we either use the Wingate protocol or the Bosco protocol.
If you want to do it yourself, take any of those other modalities, 30 seconds or so, up to 45 seconds, up to a minute. We don't really have universal standards for these things because it's going to be so different depending on whether you're on a treadmill, sprinting in a field, or on an assault bike.
What you really want to worry about is: can you complete it? And how awful do you feel afterwards? More specifically, you want to think about whether you can get close to your predicted maximum heart rate. The number we throw out is 220 minus your age. If you're 50 years old, 220 minus 50 — you should be able to get to a maximum heart rate of around 170 beats per minute. Now that number is extremely generic. If you don't get there, that doesn't necessarily indicate poor fitness. If you get higher, that doesn't mean you're any more fit. It's just a rough number.
Here's what I really want you to focus on: your heart rate recovery is the better metric. Get up to a maximum heart rate and then test your heart rate recovery. What you should be looking for is about a half a beat recovery per second. You're going to reach absolute terrible exhaustion and maximum fatigue, test your heart rate, and then count. Within 60 seconds, at half a beat per second, you should have a heart rate recovery of 30 beats per minute. Within the next minute — so a two-minute recovery — it should be about half that again, so 60 beats total. And your three-minute recovery is again half of that. Those are rough numbers to go by. If your heart rate recovery is worse than that, then we know we have a problem in your anaerobic or cardiovascular capacity.
Assessing maximal aerobic capacity (VO2 max)
Andrew Huberman: What about number eight, maximal aerobic capacity? Because what you just described sounds a lot like maximal heart rate.
Dr Andy Galpin: So this is your VO2 max. The gold standard here is to actually go into a laboratory and get this done — you put a mask on, collect all your gases, and run a very specific protocol to completion of a true maximum test. Any of the scientists will know that.
If you don't have access to that, you can do a couple of tests. One of them is called the 12-minute Cooper test. You're going to run for 12 minutes as far as you can and record the distance you covered. You can go online to any number of calculators, enter that distance, and it will tell you your estimated VO2 max.
Andrew Huberman: So that's a 12-minute sprint?
Dr Andy Galpin: A 12-minute maximum-effort run — maximum distance you can cover in 12 minutes. That's anywhere between a mile to two-plus miles depending on how fit you are.
If you want a gentler version, there is a one-mile walk test. You need either a stopwatch or ideally a heart rate monitor. This is called the Rockport one-mile submaximal test. You're going to walk a mile, record the time, record your heart rate at the end, enter those in, and those will give you estimates of your VO2 max. So that's the option for: "My knee hurts too bad," or "I've got back pain when I run." You do the walk test and it's pretty accurate if you do it correctly. Again, those are all standard calculations, so anywhere you find them, you don't have to worry about the source — they're all running off the same equation.
Assessing long-duration endurance
Andrew Huberman: Number nine — long-duration steady-state exercise.
Dr Andy Galpin: You really want to think about this not as a standard number but as: can you maintain consistent work output for over 20-plus minutes? I want you to just pick something that fits your lifestyle. Is there a loop around your house that you can do? Is there some protocol you've used before? You're simply going to test your ability to maintain work without stopping. That's all it needs to be.
Ideally, I personally like to throw a little twist in here: can you do this with nasal breathing only? That's when I feel really good about it. If you can go 30 straight minutes without needing to take a break — walking doesn't really cut it unless you're very unfit, in which case if walking 30 minutes without a break is a challenge, okay, that's your starting point. But if you can, I want you moving at a non-walking pace. I don't care what zone this is — zone 2, 3, 4, 5, I don't care. Show me you can maintain a minimum of 20 minutes of work with no breaks, no intervals, no downtime. And again, ideally breathing through your nose only.
How often to assess and how to structure testing
Andrew Huberman: How often should we be assessing our fitness for each and every one of these?
Dr Andy Galpin: I would recommend doing this full battery once a year. You could technically do all of these in two days, but a three-day split is probably best. Just say, "This is testing week." I actually love this for the beginning of the year or whenever you change your training. Just like once a year you should go to a physician and get full blood work, you do this. You're going to think, "Yeah, but I don't want to give up on my exercise routine that week." I promise you, you're not going to finish this week and think, "I didn't do very much work." It's going to feel great. And then you're going to have a very nice barometer of exactly where you need to change and prioritize your training for the next quarter, half a year, or wherever you want to go.
Which order to do them in? The non-fatiguing tests — the FFMI, the body fat composition, all that stuff — can be done whenever. I generally like to do those as your very first activity, though. We know that acute exercise can heavily influence things like body composition measurements because of inflammation, water storage, etc. So it's easiest to get that off a 48-hour rest. Make sure you don't do any hard exercise the day before a body composition test, and probably 48 hours before that. Your movement test can be the same thing — you don't want to assess how well you're squatting if you're incredibly sore from a brutal squatting session.
Then, any skill or maximum strength or power testing goes at the very beginning of the day. Any fatiguing thing happens at the end. You could easily do this: do your power test — your broad jump — you're not going to be fatigued at all from that. And on the same day, since you're already pretty warmed up, roll right into your leg strength test. And since you're really warmed up, do your leg muscular endurance test right there. Do your one-rep max leg extension, rest five to seven minutes, come back, load it to 75%, do as many reps as you can. You could roll right into your upper body test or your grip strength test or anything else. So you can knock out your strength testing and muscular endurance testing all in one day — your power jump test, your strength, and your muscular endurance.
You're going to have to come back on a separate day to do your anaerobic test — the 30-second maximum effort and things like that. You could, though, do that after your long-duration test, since the long-duration test is just going to function like a big warm-up. Or you could flip those things, or do them on separate days. You're going to have to do your VO2 max test on its own day for the most part, unless you want to do your movement or body composition assessments before those things. So you really have the ability to mix and match. Ideally, this most realistically takes three days.
You don't need to be optimal in all these areas to be in good health from this perspective. You just want to make sure there are no severe performance anchors — we don't want any of these severe constraints because you're going to get limited by that thing. What you want to do is move that up to just sufficient, get it away from the concerning zone. If you do that, that thing's not going to catch you. You're going to be able to continue to pursue optimization in the one area you have a specific passion for, which is generally what moves people. You train because you feel better, you train because you know there are all these benefits to it, but you also train because you generally like to get better at something. A lot of us have something. And you want to make sure you're not hearing, "Hey, I know you're good at endurance, but you really shouldn't train anymore." We don't want that message. I want you to love your training.
VO2 max target numbers
Before we close out, I want to go back and finish off the metrics for VO2 max because I don't think I actually gave you numbers on that. In general, for men, a minimum number we want to look at is 35 milliliters per kilogram per minute. For women, that would be about 30. We could push a lot higher on those things. In reality, I want to see men above 50, and I'm not even really satisfied until I get above 55. In fact, I want to see men above 55 and I really want to see women above 50.
Andrew Huberman: I want to add just one more metric to our discussion today, which is really just my way of saying thank you. Because if there were a metric for amount of useful information per sentence spoken, you would be at the upper level of that metric. You have this amazing ability to provide so much knowledge in a clear, concise, and well-organized format that is both interesting, grounded in science, and actionable. So on behalf of everyone listening, and certainly for myself as well, I just want to say thank you.
Dr Andy Galpin: Well, I appreciate the compliments and I'm looking forward to the next conversation — jumping right into speed, strength, and hypertrophy training and what the evidence-based best practices are for protocols in those areas.