Exercise for Health

pulling key principles out from the bottomless sea of bullshit

First of all, what is exercise? I can’t do better than wikipedia for a concise, accurate, and informative explanation (emphasis mine):

Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness.^[1]

It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic skills, improve health,^[2] or simply for enjoyment. Many individuals choose to exercise outdoors where they can congregate in groups, socialize, and improve well-being as well as mental health.^[3][4]

In terms of health benefits, the amount of recommended exercise depends upon the goal, the type of exercise, and the age of the person. Even doing a small amount of exercise is healthier than doing none.^[5]

Since what is optimal depends on so many individual factors, it is difficult to make blanket recommendations about how to incorporate exercise into your life such that health is maximized. What I’ll do instead of trying to sell a particular training modality is explain principles that might let you decide what is best for you given your own individual characteristics and preferences. When considering how to apply these principles to your own life, consider your reasons for wanting to exercise above all else. If you don’t know why you’re doing it, understanding the principles won’t be helpful in any way.

Principle 1: Energy Balance

As explored in the chapter on nutrition, energy balance will be a primary factor determining your overall health, especially in the developed world. Where hypercaloric foods are plentiful, getting a chronic surplus of energy is an omnipresent threat to the form and function of your body. Calorie balance will also determine body weight over time, so if changing or maintaining body weight is important to you, this will be an important principle to focus on. While modifying caloric intake probably has a more dramatic effect, changing your caloric expenditure with exercise can be just as effective of a strategy.

1. Steady State Cardio. If you’re trying to generate the largest possible calorie expenditure with exercise in a given time period, the highest intensity you can maintain over the course of that time period will burn the most calories. This is called steady state cardio. This might seem obvious, but a lot of people use factors with tiny effect sizes like increased post-exercise oxygen consumption with high intensity interval training (HIIT) to suggest that this is a *better* way to burn calories. It isn’t. In terms of cardio, steady state is king for generating a calorie deficit. Another nice benefit of cardio done for relatively low intensity for moderate or longer duration for getting negative energy balance is that is suppresses appetite a bit. Feeling like snacking? Go for a walk instead. Speaking of walking, it is probably the best way to reliably burn huge amounts of calories if you have the time for it as the human body has a tremendous capacity to tolerate walking. This capacity can be built up over time with other modalities like biking, running, and cross-country skiing, but walking is something pretty much everyone is capable of tolerating for high volumes, even in the developed world. The only exception to steady state not being the best way to burn calories is if you find it so tiresome/boring that you aren’t consistent with it. If you really enjoy HIIT or other forms of interval training and are more consistent with performing them for this reason, obviously some interval training will be better than no steady state cardio. This is the last time I will mention this obvious exception to every rule I’m laying out here.

2. Hypertrophy Focused Resistance Training. Next on the list of calorie burning exercise modalities is hypertrophy focused resistance training. First off, it must be acknowledged that you don’t burn very many calories while resistance training relative to steady state cardio. That said, of all types of resistance training, hypertrophy focused resistance training generally burns the most calories as fatigue is an important component of hypertrophic training stimulus and you get more fatigue by compressing more work into less time (higher rep sets, shorter rest intervals). The idea that resistance training causes you to burn more calories throughout the day is also generally overstated. The main reason resistance training is #2 here is because it does a couple very important things for energy balance in the long run. First, it increases your resting (or basal) metabolic rate (RMR) by increasing your lean body mass. With a higher RMR you burn more calories regardless of exercise. This effect isn’t huge, but it doesn’t have to be. Most people get obese very slowly over time. A steady surplus of 50 calories/day is 18,250 calories/year also known as a little over 5lbs of fat. Most people could offset this entirely by gaining 5-10lbs of lean mass (plug your own data into the Katch-McArdle formula if you don’t believe me!). Second, I think there is something to increasing your sugar storage capacity. Hypertrophy style training is particularly effective at getting muscles to not only increase in size, but also increase how much glycogen (carbohydrate) can be stored in your muscles. It is very easy on your system to take carbohydrates you consume and store them in you liver and skeletal muscles. Once these storage locations are at capacity, however, storing the excess energy becomes more difficult. I’m not going to try to cite evidence for this, this is just something I believe is likely based on thinking and reading about exercise physiology and nutrition with much of my spare time for the past couple decades. I believe it is easier on your body/healthier/less stressful metabolically if you usually have space for a few extra grams of carbs somewhere in your muscles. Consider it an added possible benefit.

3. Metabolic Conditioning. For the uninitiated, metabolic conditioning is the fancy way of describing what most people think of when they imagine what happens at a crossfit gym. Resistance training and cardio modalities/endurance training machines mixed together trying to cram a ton of work into a small amount of time. For the highly motivated, metabolic conditioning workouts do have the potential to burn more calories than steady state cardio when dealing with shorter overall duration workouts. This is because you can exceed the anaerobic threshold for particular muscle groups with one exercise, then transition to another exercise and immediately do the same thing for different muscle groups. The thing is, most people can’t tolerate the excess hydrogen ions this type of training produces for very long, although there are some genetic outliers in this regard. Since this metabolic constraint prevents most people from being capable of burning more calories/minute than steady state cardio for more than a few minutes, and this method isn’t as effective at adding lean mass as hypertrophy focused resistance training, it is #3. That said, if you have limited time and you are highly motivated, it does have the potential to be the best option for you with respect to maintaining energy balance.

4. Non-Exercise Physical Activity (NEPA). I know this chapter is about exercise, and although NEPA is not exercise nominally, I actually do consider it exercise because it meets the excellent wikipedia definition of exercise I used at the beginning. I think NEPA gets its name because most people don’t consider doing chores, farming, working construction, or just parking in the far corner of a parking lot to get more steps in to be exercise. Ironically, NEPA is great exercise. Low level physical activity performed continuously throughout the day burns an incredible amount of calories. Since the intensity is low, you have the capacity to tolerate A LOT more overall work, which adds up. To use an Army example, we generally think of forced marches for time as exercise (think 35lbs at 4mph x 1.5 hours). We don’t usually consider movement to and from a range or performing situational tactical exercises (STX) in the field as exercise. Performing squad-level STX it isn’t uncommon to end up walking 10 miles in day for a few days in a row. It is also pretty common to have rucks weighing 60-80lbs. This adds up to a tremendous amount of calories. I only bring this example up because it is a point of endless frustration in the Army. Our light infantry folks are very fit relative to other military occupational specialties (MOS), but this is because of what they do throughout the day, not what they do for physical training (which is run too damn much). Everyone thinks that the excessive running is responsible for the fitness, everyone copies, everyone breaks, and I have job security for life. Anyway, back to the topic at hand. NEPA works great, it is just more difficult to integrate into a daily routine around other life responsibilities. The easy things you can do that add up include that thing I mentioned about parking far away, using stairs, taking walking breaks at work etc.

Principle 2: Movement Quality, Volume, and Capacity

The idea that movement quality is important is somewhat controversial. There are plenty of studies that seem to indicate exercise technique isn’t that important, and that movement quality doesn’t predict injury risk. The fact of the matter is, the human body is very resilient. This resilience makes it difficult to assess the impact movement quality has on long term health, performance, and function. With all these studies that have equivocal results, there are always issues that ought to constrain the applicability of their conclusions to the question of the importance of movement quality. If you ask me, there are a couple glaring issues with this type of research. First, there isn’t a consensus on what constitutes ‘quality’ movement for a given task. Second, when looking at injuries, massively heterogeneous conditions like ‘back pain’ get treated as one homogeneous condition. What constitutes quality movement to avoid aggravating one condition instead aggravates another. Lump it all together and you get equivocal results. Go figure. As a physical therapist the importance of movement quality is so obvious that I’m blown away that people can use literature to convince themselves otherwise. People come to me performing exercises that hurt, and by making subtle adjustments to the exercise it doesn’t hurt anymore. This happens along predictable pathways. If you think movement quality doesn’t matter, then you haven’t been injured yet. If you train hard, you’ll probably learn otherwise soon enough (unless you’re one of those people who thinks it doesn’t matter, but nonetheless has excellent movement quality - those folks will of course be fine while their admonitions to not worry so much about technique will wreck those unfortunate enough to listen to them).

The importance of movement quality is directly proportional to training volume. If you don’t train very often, then movement quality isn’t as important. If you train a lot over a period of years, it becomes extremely important. Lifestyle factors also come into play. If you sit at a desk all day, that loads certain tissues quite a bit. Put another way, this activity uses up some of the capacity of various tissues. In the case of prolonged sitting 8-10 hours/day x several years, this consistently eats up a lot of capacity of the posterior annulus of lumbar intervertebral disks. If this is you and you start going to the gym and squatting ass-to-grass with a massive butt wink then you’re going to blow through the capacity of that annulus to contain the nucleus of the disk a lot faster than someone who walks around all day. To be clear, if that happens then your back is going to hurt and your capacity for pain free training will be adversely impacted. This is, of course, just one example. There are tissues everywhere in your body that have a certain capacity for load. As load is applied, capacity decreases. When it is removed, capacity begins to recover. There are tissues like the meniscus in the knees, the labrum in the hips and shoulders, and lots of things in the spine that get stressed a lot with ‘poor movement quality’ that can be reduced with ‘good movement quality’. I mention these tissues because they all have somewhat limited blood supply and take a long time to heal. Unfortunately most people have to learn about this the hard way. Consider this section my attempt to get to you take the easier path and take movement quality seriously. All of your tissues work best when they get some loading within their capacity. As we say in the biz, motion is lotion, and motion is used to load various tissues. Also, to reiterate, you can get away with not doing the stuff I’m going to mention for a long time. For smaller and lighter individuals with low physical demand jobs and recreational activities, you might be able to get away with ignoring everything I say here for your entire life. If you weigh more than 200lbs and want your body to perform above average, though, I can almost guarantee that ignoring the stuff I outline here will lead to injury (but chances are you’ve already had one if you have any kind of training history).

All human movements can basically be broken down into six fundamental patterns:¹ Squat/lift, lunge, twist, push/pull, gait (carrying, running, walking), and maintaining balance. I'll cover some examples of things that are broadly applicable to most people exercising for health for each of these fundamental movements.

1. Squat/Lift: As a general rule, when high torques are passing through the spine, you don’t want the spine to be moving. With respect to loading a squat or lifting pattern this means that you don’t want your spine to move. You hips, knees, and ankles can all move a lot. You don’t want your spine moving. This habit can be generalized to a great variety of activities from helping a neighbor carry a couch to picking up a heavy package. To protect the knee push through the middle of the foot (to do this your entire foot has to be in contact with the ground). Finally, don’t let your knees collapse in (keep them generally in line with the orientation of the hip and ankle).

2. Push/Pull: Keep your wrists neutral.

3. Twist: Again, to preserve the spine torque and motion should be inversely related. A good example of fast motion with low torque is the follow-through of a golf swing. An example of high torque no motion are overhand and hook punches in boxing. For both of these examples power is generated in the hips. What not to do? The Russian twist exercise with a medicine ball.

4. Gait. For loaded carries maintaining that same neutral lumbopelvic posture will allow athletes to carry the most with the lowest risk. For running keeping the cadence (foot strikes/minute) between 170-180 forces runners to use mechanics that better distribute load between hips, knees, and ankles.

5. Lunge. No matter what variation you do, I like using a lot of range of motion in the hips, knees, and ankles. It is easier to get more range with a neutral spine using lunge variations than squat/lift pattern, and loading through these ranges is a good way to enhance mobility and protect against injury.

6. Balance. Incorporating single leg or arm movements into training introduces a balance/stability component. This is a useful training stimulus and is also the least taxing on tissues because balance becomes the limiting factor vs. strength or tissue capacity.

Principle 3: SAID and Physiological Adaptation

There is a principle in exercise science referred to as Specific Adaptations to Imposed Demands, or the SAID principle. Keeping this principle in mind if you have specific performance goals is very important. The physiological mechanisms by which we adapt to stimulus are varied and complex, but the widely applicable generalization is that by whatever mechanism, any given stimulus is likely to cause adaptations that improve performance at executing whatever function provided that stimulus. You want to get faster at running? Run fast. You want to lift heavier weights? Lift heavy weights. Most people rightly incorporate this principle into whatever exercise they do. I like to pair this with another consideration, however, because it isn’t always so straightforward. Sometimes, the best way you can improve at something is to optimize for a particular physiological adaptation that clearly improves performance on a given task. Let’s look at some examples.

1. Cardiac Stroke Volume. Cardiac stroke volume (SV, or how much blood your left ventricle has the capacity to pump in a single stroke) will generally be beneficial towards improving performance in any activity that is highly demanding for the cardiovascular system (basically anything where the duration of the effort is more than a minute or so). The longer the duration of the activity, the more the benefits of an increased maximal cardiac stroke volume will stack up. The reason I use this example is because there are very specific cardio training parameters that maximize stroke volume over time. Basically getting the heart rate between 140-160bpm for 40-45min is optimal. Do this on a daily basis for a month and your SV will increase dramatically, I guarantee it! Higher heart rates don’t allow for complete filling of the left ventricle so it doesn’t get as full of a stretch. Do this any longer and you can’t get the optimal frequency of stimulus as it becomes too difficult to recover from daily workouts.

2. Fat Mass. I consider modifying body composition physiological adaptation. Targeting minimal fat mass is a great way to improve the aesthetics of your body. It is also a great way to improve performance with any activity where body weight is a factor (most of them). Also, lower fat mass is highly correlated with overall health, most probably because being lean generally equates to good energy balance. There is a certain point of leanness beyond which hormones will be adversely effected, and for folks trying to get as strong as possible relative to external loads fat mass can be helpful. It is also very difficult to stay below your ‘set point’ of body fat that I believe is largely genetic. All that said, for a great many folks reducing fat mass is a physiological adaptation that will help with a variety of goals.

3. Mitochondrial Density. This is basically how many mitochondria you have/gram of contractile tissue in a given muscle. This is a useful target for improving performance for specific cardiovascular challenging activities. The best way I know of to optimize for this variable is high intensity interval training (HIIT). Perform whatever activity you’re trying to get better at with maximal intensity for anywhere from 30-90s. I think this adaptation is why 400m sprints work so well to improve middle-distance running performance. I combine this with #1 all the time to help Soldiers get 2-mile run time PRs.

4. Muscle Cross-Sectional Area/Hypertrophy. There are many activities for which increasing muscle mass doesn’t help much. There are many others for which it is counterproductive (think of a marathon runner adding upper body muscle mass). For general health, I think most people would be best served by optimizing for this physiological adaptation. Why? Because reaching your genetic potential for building lean mass takes forever. Let me explain what I mean by that. Most people won’t reach their genetic potential for building muscle for a solid 10 years of consistent training. Once you get there, though, you now have a ton of flexibility that you didn’t have before. You could lose most of that mass by simply not training and dieting hard for a much shorter period of time. I’m sure you’re thinking that doesn’t sound like a great deal, but wait, there’s more! There is a process called myonucleation. When muscle cells hypertrophy, then need more nuclei to support the larger sized cell. When muscle cells are exposed to disuse and hypocaloric conditions, they do atrophy quite readily, but these myonuclei tend to remain. This is one of the potential reasons it is easier for folks to regain muscle than it is to build it in the first place.

   

   The classic example of this is the Colorado experiment where bodybuilder Casey Viator gained over 63lbs in 28 days, supposedly without drugs.² Digging into the story Casey was quite atrophied having recently had to take a significant amount of time off from disuse atrophy as described in the linked article. Most of us who have taken time off and returned to training have experienced this, so to all of us, this is obvious. To everyone else, know that hypertrophic adaptations are more stable than you might think judging from sight alone.

   Another key reason building muscle is important for lifespan health is that muscle wasting tends to be one of the major complications with aging. When age-related functional decline begins, this can generally be attributed to decreases in lean muscle mass and strength. We go through our comfortable lives with massive functional reserves to make it through our days unassisted past our 50s for the most part, but getting into your 60s those who never spent any time using their muscles are in for a rude awakening. Now, to be clear it is never too late, and geriatrics benefit tremendously from resistance training, but establishing those habits that late in life is probably tougher than doing it earlier on. You can also build up a much larger reserve by starting earlier, and this reserve has the potential to keep you functional until you pass quickly in your sleep at some ripe old age.

5. Strength. When I think of optimizing for strength, I think of neurological efficiency and coordination as opposed to building muscle cross-sectional area. Thinking of them as two separate adaptations is helpful for whatever goals you are pursuing. Optimizing for strength is probably best for when you have a specific activity or performance event in mind. If you don’t have anything in mind, I would focus on hypertrophy until you do. It takes a lot less time to get the neurological adaptations necessary to optimize strength for a particular movement than it takes to build the cross sectional area of the muscles that contract to produce that movement. Put another way, focusing on hypertrophy when you don’t have a specific goal in mind will allow you to get a lot stronger a lot quicker at any given specific task.

Principle 4: Health vs. Performance

Never forget that optimal health and optimal performance aren’t the same thing. At a certain point, optimal performance will not be healthy. Chasing extremes of performance has a cost. It requires that you compromise other things, and at a certain point one of these things will probably be your long term health. It is here that I want to talk about general fitness guidelines for things like cardio and resistance training. You’ll see recommendations for a certain number of minutes/week for these things. These recommendations are based on correlation or are arbitrary. The primary literature that selected the weekly recommendations for activity simply picked an amount of exercise and found that it improved whatever measures of health they were examining.

1. Health. Finding the optimal amount of exercise for health depends on the individual. Essentially, it is as much as you want to incorporate into your routine without getting injured. Since psychological well-being is a component of health, we can’t discount the fact that some people hate exercising. For some, exercising at all is a chore and they need to kind of trick themselves into getting it in. These are the kinds of people who can really benefit from focusing on maximizing NEPA. Even for these folks, the tiniest amount of resistance training can have substantial benefits. I think everyone who does some resistance training finds that it is worth the investment. As I try to make clear here at H2F man, there is a large subjective component to health. As such, the right amount of exercise will vary quite a bit between individuals.

2. Performance. The optimal amount of exercise for performance is infinitely less variable. Since we’re talking performance here, we have an objective standard, which means that there are right and wrong answers, and that there is a way to test who is right and who is wrong. The right amount still varies between individuals, but so much at similar levels of performance. Instead of being determined by how much you want to exercise like health, an optimal exercise program for performance is how much exercise you are capable of handling without getting injured. Since the answer to that question is speculative, you can expect that people training for performance are going to get injured a lot more often. The margins are much narrower.

So, is there an amount of exercise/week that it optimal for everyone as a guideline? No, there isn’t. There are amounts that are correlated to what works well for a lot of people. Use these guidelines if you want, or you can follow my strategy for developing a comprehensive exercise program.

Building Your Program (or use someone else’s)

1. Decide how often you want to exercise and how to integrate it into your routine. This includes time of day, and day of the week.

2. Consider the principles above and fill out the time you’ve identified with the types of exercise that fit with your goals. Keep in mind constraints in terms of equipment, and how to use your time most efficiently.

3. Train harder than last time.³ No matter what you do, if you do just a little more than last time this will ensure progression. Another set, another couple reps, more weight, increased duration, increased intensity. Just a little bit harder than last time and you’re moving in the right direction.

4. If all of this seems too daunting, just pick something off the internet and stick with it to the best of your ability. Doing someone else’s 12-week program is a great way to learn a lot of new stuff and learn how your body responds to different styles of training. I would still recommend keeping the principles I’ve outlined here in mind, though, if only to better interpret your results!

1. Credit to Stu McGill. These are the patterns he uses to describe all types of movement as a highly published PhD in biomechanics in his book Ultimate Back Fitness and Performance.

2. Even with drugs, this is insane.

3. Yes, I’m stealing this from Greg Doucette because it is a brilliant way of expressing the concept of progressive overload.