Preface. This is a summary of Herman Pontzer’s 2019 “Humans evolved to exercise. Unlike our ape cousins, humans require high levels of physical activity to be healthy” in Scientific American. As fossils decline, it’s almost guaranteed you’ll use more muscle power, so get in shape now…

Also, your personality as measured by the Big Five Personality traits will be better if you exercise. Couch potatoes are less conscientious, open, agreeable, and extroverted. The link with exercise was relatively strong. Physical activity predicted personality better than disease burden did (Stephan 2018).

Alice Friedemann   www.energyskeptic.com  author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report

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Pontzer, H. 2019. Humans Evolved to Exercise. Unlike our ape cousins, humans require high levels of physical activity to be healthy. Scientific American.

Apes are a lot like us, orangutans, gorillas, chimpanzees and bonobos share over 97% of our DNA. But the differences are interesting. Our bodies changed dramatically over the past two million years with a larger brain, invented tools, language, hunted and gathered, and our survival depended on lots of physical activity.

We couldn’t just sit around like chimpanzees and eat fruit all morning, nap, groom, then gorge on figs, hang out with friends, group, another nap, and more fruit and some leaves. Likewise, oranguatans and gorillas are also idle and sedentary, spending 8 to 10 hours resting and then 9 or 10 sleeping, walk about 1.8 miles a day and climb about 330 feet, equal to another mile of walking.

Humans who try to slack off this much risk serious health problems. Without at least 10,000 steps a day, the risk of heart disease, diabetes, and metabolic disease increases. Sitting at a desk or in front of a TV for long times ias also associated with an increased risk of illness and a shorter life span. Basically, physical inactivity is on par with smoking as a health risk.

Yet our ape cousins can get away with lolling around. their blood pressure doesn’t go up, diabetes is rare, and their arteries don’t harden and clog with cholesterol.

Diet is destiny. About 1.8 million years ago our ancestors began to evolve to hunting and gathering, which required a great deal more walking to find animals and edible plants. Today hunter-gatherers get roughly have of their calories from plants, and cover 5.6 miles (12,000 steps) to 8.7 (18,000 steps) in search of food, traveling 3 to 5 times farther every day than any of the great apes. Before we invented the bow and arrow, humans may have had to be even more active.

On top of that, we evolved to run prey to exhaustion (Bramble 2004).

Although we’ve long known exercise is good for us, it appears that it’s good for every organ system even down to the cellular level. Our brains hae evolved to reward prolonged physical activity with endocannabinoids which is where the so-called runner’s high comes from. Many have argued that exercise helped enable the massive expansion of the human brain to the point where we require physical activity for normal brain development. Exercise releases molecules that promote neurogenesis and brain growth, as well as improve memory and stave off cognitive decline in old age.

Our maximum sustained power output (VO2max) is at least four times higher than the great apes due mainly to our leg muscles which afe 50% larger with a much greater proportion of slow-twitch fatigue resistant fibers than the legs of other apes. We have more red blood cells to carr oxygen to working muscles. Exercise accelerates the rate at which our cells function and calories are burned.

Exercise has been sold as a way to lose weight. But it isn’t optional, and weight loss is probably the one health benefit it often fails to deliver. Unfortunately, exercise doesn’t increase energy expenditure, it just makes our bodies work better. This is why those hunter gatherers walking almost 9 miles a day don’t expend much more energy than sedentary Westerners.

Here are some of the ways we do know exercise benefits us. It reduces chronic inflammation which can lead to heart disease. It lowers levels of reproductive hormones (i.e. testosterone, extrogen) which reduces the rate of reproductive cancers. It probably blunts the morning rise in the stress hormone cortisol. It reduces insulin insensitivity, the immediate cause behind type 2 diabetes, and shuttles glucose into muscles instead of fat. Exercise also improves the immune system, and produces enzymes that help clear fat from circulating blood.

References

Bramble D. M., Lieberman D. E.. 2004. Endurance running and the evolution of Homo. Nature 432.

Pontzer, H. 2017. The crown joules: energetics, ecology, and evolution in humans and other primates. Evolutionary anthropology 26:12-24.

Pontzer, H. 2017. Economy and endurance in human evolution. current biology 27.

Stephan, Y., et al. 2018. Physical activity and personality development over 20 Years: evidence from three longitudinal samples. Journal of research in personality 73: 173-179