Be Swole for Science: How our Evolution Encourages Exercise

I've had the great fortune of studying and working with some intelligent and intellectual people. Most of my peers are pretty well-rounded. If someone is motivated enough to do all their homework, that motivation probably spills into other aspects of their life. Some of the smartest people I’ve met are smart because they’re hard working, and as a result of that work ethic, they’re also some of the fittest people I’ve met.

Every now and then, however, I meet a stereotypical nerd. I typically use the word “nerd” with affection. Nerds are the shit. But I don’t like shallow stereotypes, and I especially don’t like when people play into those stereotypes so one-dimensionaly. Something especially aggravates me about the unfit pasty guys who have no identity outside of being smart or a nerd. Probably because I was one of those guys as a kid. Call me a hater. Maybe I am.

Swole for No Reason?

So every now and then I meet the nerd who thinks life is all about living intellectually or something. Why exercise? Not only can you make a fine living with your mind, the pursuits of the mind are the only pursuits of value. Seeking physical strength is pointless at best and base at worst. Meat-heads are the enemy. Blah, blah, blah. 

I’ve written a lot about being fit lately, and one of my friends chidingly shared with me an article which discusses being "swole for no reason.” “Swole,” if you don’t know, is slang for being jacked, which is slang for being buff. The author, a writer, recounts his experience trying to get swole. After failing to achieve swoleness, the writer experiences "the delusion of getting out of shape as a form of martyrdom.” Why should he be swole? Writers don’t need to be swole. Wouldn’t it be silly for him to go out and get fit? How shameful it would be if he was swole for no reason.

While I’m sure (or at least hope) that the author as joking, the sentiment in the article is not uncommon. The author describes a self-righteousness that I’ve seen from many of my one-dimensional nerd friends. “Why do you bother working so hard on that meat bag you carry around? What’s the point of trying to get strong and fast and have shredded abs? Stop being so crazy and hang on the couch with us a bit more."

Granted, there’s some amount to fitness that’s extrinsically pointless. Like climbing a mountain because it’s there, I’ve been working to shorten my mile time gradually for years (5:10 as of this writing!), although I doubt there will be a situation in my life where there I’ll ever need to run that fast. Sure, it’s nice to know I can and that it may be of use, but having that ability on reserve is like keeping a defibrillator around even if you have no history of heart attacks. If you ever need the thing, you’re probably in a situation where it won’t make much of a difference.

Despite the pointlessness of some fitness, however, there’s a whole host of reasons for being swole, or for at least exercising frequently; even if you’re one of the intellectual martyrs who doesn’t care about how looking fit because only the inner-mind is beautiful or whatever. We evolved to use our bodies, and our bodies evolved to require use. Without activity to challenge our physical structure, humans become susceptible to debilitating diseases. 

"We Really Did Evolve to Use it or Lose It"

Daniel Lieberman is a paleoanthropologist and a biology professor at Harvard; he was part of the team that published the widely-circulated research paper showing the benefits of forefoot running. In his book, The Story of the Human Body: Evolution, Health, and Disease, he covers the current state of our understanding of how and why humans evolved to have the bodies we have today. Lieberman then discusses how our evolutionary history can inform the way we take care of our bodies. The environments we have created for ourselves have and continue to increase our life expectancy and our quality of life. But the same environments also lead us to contract some preventable diseases and disabilities, leading to lives filled with longer periods of morbidity. For example, most people now have an abundant access to food and starvation is at an all-time low. But many also have access to too much food and the incidence of type 2 diabetes is at an all-time high.

So what does our evolutionary history and biology say about whether or not you should be swole? 

Lieberman discusses some biology that indicates that exercise is so fundamental to our bodies that the lack of exercise can lead to disease and decrepitude. If you have no reason for being swole other than swoleness itself, you’re still doing your body several huge favors. If you’re afraid of being swole for no reason or if you think that being swole is pointless, Lieberman gives a few reasons why you should consider swoleness for the sake of your health and quality of life. (To be clear, Lieberman isn’t advocating for your swoleness. I am. And I just think Lieberman offers good supporting evidence.)

Life is Plastic, It’s Fantastic.

Evolution drives towards one thing: survival. One incredibly valuable trait for survival is adaptability. Even within one lifetime, climates and conditions can change enough that poor adaptability can lead an organism to its death and cause it to not pass on its genes. Fail.

Given our existence today, we can tautologically say humans are good at adapting, or at least good enough. Studies of our epigenetics (the non-random changes in our genes caused  by external factors) have shown that we can quickly adapt within a generation to better suit our conditions. If calories are scarce, it becomes advantageous to survive on fewer calories — babies born to mothers who lived through food shortages will be born smaller and with slower metabolisms to better survive the energy crisis. 

Our adaptability is not purely transgenerational; much of our adaptation to our environment happens within our own lifetimes. Our bodies adjust their characteristics in response to environmental stimuli. If you lift something heavy and stress your muscle tissue, your muscle tissue grows in response to better lift heavy things. But muscle tissue is costly to maintain, so if you have no stress telling your body it needs muscle to move things, your body will quickly get rid of the calorically expensive tissue.

This phenotype plasticity allows our bodies to become strong when we have the resources available to us and it allows us to become thrifty when there is no need for such strength, giving us the adaptability to thrive as best as possible given our environmental situation.

While phenotype plasticity is great for adapting to ever-changing environmental stresses, it’s not so great for a non-stressful and unchanging environment, such as the one most of us were born into.  We no longer need the same adaptability in a world of abundant food, but our bodies haven’t changed as fast as our environment, and they still function cheaply. So even if you’re not starving, your body will eat all your muscle away in preparation for starvation unless you exercise to signal to your body that the muscle is worth keeping. 

Muscle Mass

So what if your muscle atrophies without exercise? We don’t need gains and gunz in order to live a healthy life, right? That’s partially true. We don’t need the bodies of Greek gods, but we do need some minimum amount of muscle to get out of bed, walk around, lift our luggage, avoid injury, use the toilet, and do all the other things a modern human needs to be able to do to live a full life.

Unfortunately, our bodies suck at letting us keep this requisite muscle minimum. Without exercise, our bodies will eat away our muscle until we literally can’t stand it and become immobile. For most young people, this isn’t a problem. I've never met a person who couldn’t walk in their 30s just because they didn’t exercise, and you probably haven’t either. But as you go up in age by decades, you can probably think of more and more people who need assistance walking in some form or another, or who need assistance getting out of chairs or walking up stairs. Of course, as people get older, their bodies break down from aging and years of wear. Our great technological innovations are allowing us to live longer than ever before, so maybe we just didn’t evolve to support ourselves into old age.

But that age is the dominant controlling factor in muscle degeneration doesn’t seem to be the case. One study, titled Chronic Exercise Preserves Lean Muscle Mass in Masters Athletesexamined muscle tissue in recreational athletes aged 40-81 and found that declines in muscle mass were more closely correlated with disuse than they were with old age. It sounds like an obvious observation until you see some of the MRI comparisons published in the study and get an idea of how much a difference a lifetime of exercise can make.

The images below are MRI scans from the study of the quadriceps of three people. In the top image are the quads of a 40-year-old triathlete. The middle image shows the quads of a 74-year-old sedentary man. The bottom image shows the quadriceps of a 70-year-old triathlete. 

Image from:  Chronic Exercise Preserves Lean Muscle Mass in Masters Athletes  published in  The Physician and Sports Medicine  . 

Image from: Chronic Exercise Preserves Lean Muscle Mass in Masters Athletes published in The Physician and Sports Medicine

The athletes who had a habit of "chronic exercise” (exercising 4-5 times per week) showed no significant decline in absolute muscle mass or loss of strength with age. Not only does this maintenance of muscle mass and strength contribute to a longer life of independence and mobility, the study cited that older adults with reduced muscle strength have higher mortality. 

So if you’re worried about being swole for no reason, not only will being swole increasing the amount of years you can live without disability, it may increase the odds that you’ll live an even longer life. 

Bone Density

Another disease associated with disuse is osteoporosis. Our bones are constantly being worn away but the forces of our activity, such as walking or running. In our youth, we can quickly regrow that bone, but the ability to grow new bone decreases as we age, and, over time, small structural deficiencies emerge where we have lost more bone than we can regrow. Eventually, the small deficiencies become a large deficiency, and the bone crumbles to a point where regrowth is no longer possible.

While we can’t (yet) change the fact that our ability to regrow bone decreases with age, we can change how long we get to live with a healthy skeleton. Similar to how they treat muscle tissue, our bodies are cheap when it comes to bone density. When we run, jump, and otherwise stress a bone, we send signals to your body that the bone needs repair, and our bodies react by starting repair processes. The more we stress our skeletons with activity, the more our bodies maintain their structural strength. Unfortunately for sedentary kids, most of our bone density is established at a young age. If you didn’t exercise much as a child and you’re now an adult, you’re not going to drastically change your bone density, but you can mitigate degeneration with exercise. As Lieberman cites, "Dozens of studies prove that high levels of weight-bearing activity considerably slow and sometimes even halt or modestly reverse the rate of bone loss in older individuals."

Perhaps dense bones don’t mean too much for you — you have no interest in landing long jumps or heavy punches. Getting swole may still be worth your efforts if you don’t want to be stuck in a wheel chair or with a false hip sometime in your senior years. Just as using your bones causes their repair, the opposite is also true. If you don’t stress bone, the repair process doesn’t kick in properly, and your bones start to lose integrity. Think of any space-based science-fiction you’ve read; Captains who spend too much time in space develop a hobble associated with weak bones. We’re constantly stressed by gravitational forces, and in a zero-G environment, bones rapidly degenerate. Now, most of us are stuck on Earth for the foreseeable future, so we have no excuse for weak skeletons. All it takes is a bit of slowness to keep our meat bag strong.

Heated Pads and Advil, 'Cause Back Pain is Mad Real

If the inability to generally function due to muscular atrophy or a crumbling skeleton isn’t enough of a stick to convince you of the virtues of being swole, a less dramatic but more relatable reason may change your mind. Frank Herbet said fear is the mind killer, which makes me suspect that he never suffered from lower back pain.

If you told the 20-year-old version of me that I’d ever fear back pain, he would’ve laughed at you. It sounds like such a trite problem. Something old people complained about when their 401(k) is doing too well. And then one day I pulled my back lifting a 45-pound bar just to set up for a workout and thought I was going to die.

Lieberman discusses low back pain in The Story of the Human Body as an example of the unanticipated nature of  diseases of disuse. As Lieberman cites, between 60 and 90 percent of people get lower back pain, depending on where they live and what they do, and unfortunately, most don’t really know how to treat it. If you’ve ever suffered from low back pain, you know how annoying the problem is. It’s constant, annoying, and incredibly difficult to treat. You end up resorting to heated pads and voodoo chiropractic magic; anything to make it go away.

As Lieberman says, a healthy back requires flexibility, strength, and endurance. So it’s not surprising that one of the hypothesized culprits for low back pain is chronic sitting. I tried summarizing why exercise is good for preventing lower back pain, but I really liked the way Lieberman wrote about it, so I’ll quote him at length here with the strong suggestion that you read his book:

"A normal, fit back needs to have a considerable degree of flexibility, strength, and endurance, as well as some degree of coordination and balance. Since people who are mostly sitters tend to have weak and inflexible backs, they are more likely to experience muscle strains, torn ligaments, stressed joints, bulging disks, and other causes of pain if and when they subject their backs to unusual, stressful movements. As predicted, people in developed countries who suffer from back pain tend to have a lower percentage of slow twitch fibers, which means that their backs fatigue more rapidly, and they also have lower core muscle strength, reduced flexibility in the hip and spine, and more abnormal patterns of motion…

"A normal back doesn’t get pampered by chairs but instead is used with varying degrees of moderate intensity all day long, even during sleep. The adoption of agriculture was probably bad news for human backs. Now we face the opposite problem, thanks to comfy chairs, as well as shopping carts, rolling suitcases, elevators, and thousands of other labor-saving devices. Liberated from overstressing our backs, we suffer from weak and inflexible backs. The resulting scenario is all too common: for months or even years, you may be pain-free, but your back is weak, hence susceptible to injury. Then one day you reach down to pick up a bag, sleep in an awkward position, or fall on the street, and— WHAM— your back gets injured. A visit to the doctor’s office usually results in a diagnosis of nonspecific back pain, plus a handful of medicines to alleviate your suffering. The problem is that once lower back pain begins, a vicious circle often ensues. A natural instinct is to rest when following a back injury and then to avoid activities that stress the back. However, too much rest only weakens the muscles, making you more vulnerable to another injury. Fortunately, therapies that improve back strength, including low-impact aerobic exercise, appear to be effective ways to improve back health."

If you’re a desk jockey and you spend your work day sitting, you should probably spend some amount of time working out the muscles that get weak or tight from sitting too long. (The region I see most of my friends struggle with is the hip-flexors. If you’ve ever seen a nerd walk slightly bent over, like he’s carrying a heavy backpack, it’s probably because his hip-flexors are too tight from sitting all day and all night.) If you are that nerd, sign up for a membership at your local gym and spend some time getting swole so that you’re not stuck with a life full of Advil and chiro visits.

Learning More About Evolution and Being Human

If you’re unconvinced that being swole has more to offer than looking good shirtless, I recommend reading the entirety of The Story of the Human Body. In it, Lieberman discusses the evolutionary basis for our bodies’ functions and how the swelling of non-communicable diseases such as diabetes, heart disease, and cancer can be tied to our activity levels and diet. And if you really are the stereotypical nerd who hates exercise because you think it’s pointless, you’ll at least learn some good paleoanthropology and get a better idea of how your meat came to be. I’ve found it to be one of the more approachable books on the subject, and I have no formal education in any amount of science.


If you are convinced that you need to use your bomb body before you lose it, I wrote a post listing my favorite resources for getting in shape (most of them are books, ya nerd).

The image in the banner came from loonatic on Flickr by way of the Creative Commons license.