Why Studying Evolutionary Anthropology is Important
To define it, evolutionary anthropology is the study of the evolution of human behavior and biology. We try to ask not only how certain human behaviors and physiology develop, but why we have evolved such adaptations in the first place. Evolutionary anthropologists address these questions through a variety of methods including: the study of behavior of modern humans in both industrialized and more traditional societies, comparing similar behaviors seen in both humans and another species, and studying fossils of our ancestors. Understanding the why gives us important insights into numerous areas of life - from autoimmune diseases, to child rearing, to mental health. However, today, we are going to focus on why humans need exercise in the first place.
What Kind of Exercise Did We Evolve for?
On the surface this seems like an obvious question: we exercise to stay healthy, look good, feel good, and socialize. Time after time countless studies show how important exercise is to maintaining bone mass (Guadalupe-Grau et al., 2009), reduce visceral fat (Ohkawara et al., 2007), help buffer against depression (Harris et al., 2006), and reduce or even reverse pre-diabetic symptoms (Malin et al., 2012). A 30 year study that followed thousands of nurses found that regardless of their BMI, nurses who exercised more reduced their mortality rates by 50% (Hu et al., 2004). Given these numerous benefits, it seems logical that we’ve evolved to gain such benefits from physical exercise. This is what many anthropologists thought until they started studying the few remaining hunter-gatherer societies, people who get food through foraging and hunting, and subsistence farmers.
The "Athletic Savage" Myth
Interviews with these groups of people revealed that none of these groups have ever done physical exercise like running or lifting weights just for their health! Yet, some of these groups such as the Aché from south America and the Hadza from Tanzania have made the rounds in global news as having incredible cardiac health and being very fit. You may have heard of a small population of native Mexican people called the Tarahumara, which are famous for their long-distance endurance running. For years, these groups seemingly incredible health and fitness have been explained by perpetuating the myth called the “Athletic Savage”. It states that because these “savages” are living simple, “honest” lives away from the trappings of modernity (cars, small apartments with elevators, processed foods, offices), they are just naturally healthier, happier, and more athletic. Worse, some people think that these groups are genetically predisposed to being healthier than everyone else.
Hunter Gatherer's Reality
Research has shown that none of the above is true. Hunter gatherers and subsistence farmers are healthy because they have to work their asses off every day to survive. For example, men of the Hadza walk about 10-15kms every day searching for game and honey. women walk about 4-7kms collecting nuts, fruit, and tubers (Pontzer et al., 2015). While women walk shorter distances, they spend considerable time and energy digging and prepping their food by pounding and grinding it. This doesn’t even address the physical activity that goes into making and building everything they own. While subsistence farmers like the Tarahumara don’t walk as much as hunter gathers, they actually spend more energy per day than them weeding, ploughing, planting, collecting, and processing their grown food without the aid of machines or even work animals. All told, these groups spend on average about 135 minutes a day engaged in moderate to high intensity physical activity, and another 4 hours a day of light physical activity (Raichlen et al., 2017).
Understanding Human Evolution
Hunter-gatherers are important in our understanding human evolution as this subsistence strategy is thought to have coevolved with the genus Homo, 2 million years ago. By the time modern humans emerged 1.7 million year later, hunting and gathering had become an integral aspect of our species until the invention of farming 12,000 years ago* (Bramble & Lieberman, 2004). Meaning that modern humans not only evolved to handle this level of physical activity on a daily basis, but also evolved adaptations that required this level of activity to maintain critical health functions in the body. For example, moderate aerobic activity causes muscles to release anti-inflammatory chemicals which help regulates immune system function and protect us from chronic inflammation (Pedersen, 2013). Such exercises also help regulate our metabolism by causing muscle cells to regenerate/create more receptors to take in much larger quantities of sugar from the blood stream (Sylow et al., 2017). It is the maintained of these and numerous other critical systems that requires people in industrialized nations to exercise for the sake of health.
Evolutionary Mismatch of Modern Lifestyle
Compared to most hunter gatherers and subsistence farmer groups, modern Americans are between ½ and a 1/10 as active (Lieberman, 2020). Modern trappings such as cars, grocery stores, delivery services, and processed foods have drastically reduced the amount energy and physical activity needed to collect and prepare food. Combine this with adaptations that cause us to rapidly turn excess energy into fat to buffer against unstable food supplies, and you get a country where a third of adults are obese, a condition literally unheard of in hunter-gatherer societies (Ogden et al., 2017). When an adaptation that was beneficial in a past environment suddenly becomes maladaptive due to a sudden change in environment it is called an “evolutionary mismatch”. Evolutionary mismatches can be identified when certain diseases or conditions become more common and/or severe than in the past. In addition to obesity, disease and conditions linked to lack of physical activity include cardiovascular disease, metabolic disorders, Alzheimer’s, depression, and anxiety (Lieberman, 2020).
So How Much do I Need to Exercise?
Now I’m sure many of you are asking, “great, I get why I need to exercise, but how much? And what types of exercises are best? Given that every person is different and I’m not a certified personal trainer, physician, or anywhere near to an expert in human physical activity, I’m going to give only general tips that I have tried to incorporate into my life. First is that you can always be more physically active, the U.S Department of Health and Human Services recommends a minimum of 150 minutes of dedicated exercise a week. This is based on several long-term studies that found 150 minutes to be the minimum amount of exercise required to start seeing significant decreases in yearly mortality risk (Pate et al., 1995). However, given that this is far below the 945 minutes a week minimum that hunter gatherers and subsistence farmers do, this is a very low bar. Especially for those interested in exercise to lose weight, remember, we evolved to hold onto fat like Ebenezer scrooge holds on to lose change. Studies show that people who engage in the bare minimum 150 minutes of brisk walking lose little to no fat, however, when subjects were made to walk twice this amount they lost an average of 6lbs after 12 weeks (Flack et al., 2018). Exercise is also a key component in maintaining weight loss when dieting, One study with Boston policemen showed that while exercise did not greatly increase weight loss caused by dieting, those who did not exercise quickly regained the weight after ending the diet while those who exercised did not (Pavlou et al., 1989).
Cardio or Weights?
As to what type of exercises to do, it will largely depend on the individual, but the goal should be a blend of endurance and weight training. Endurance exercises like walking and running over extended periods of time are necessary to activate many of the muscles anti-inflammatory and metabolic regulating functions, as well as maintain cardiac health. While weight training does not provide these benefits to the level of endurance exercises, it is critical to maintain muscle mass, strength, and functionality of the muscle itself, especially as we age. Exercise won’t help you stay healthier if you’re too weak to even exercise.
I hope has article given you a deeper appreciation about why exercise is so important to our health, and how understanding our evolution can help us become even healthier. I would like to reiterate one more time that before you start trying to drastically change our physical activity patters, please consult your physician and a personal trainer to ensure you don’t hurt yourself!
*N.B. It would be inaccurate to say that modern hunter-gatherers live exactly as our ancestors as practices change over time, and all groups have experienced rapid changes in lifestyle due to global modernization, but it’s as close as we’ll get.
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To give everyone some background about me, my name is Jack Grady, and I am what you call a nerdjock. I have always been interested in animals from a young age, this love of wildlife has led to work with lemurs at the Duke Lemur Center, spotted hyenas in Kenya, and now chimpanzees in Uganda. To further pursue my passion, I earned a BA in biology and evolutionary anthropology and a Master of Science in evolutionary anthropology.
Not only am I a scientist, I’m also an avid powerlifter and have competed in multiple local powerlifting events, winning one, as well as competed in sports ranging from wrestling, fencing, to even quidditch.
Being both an evolutionary anthropologist and a lifter has caused me to appreciate and understand exercise not only from a more scientific perspective, but with a critical evolutionary aspect as well.