What to expect this week:

Would you consider yourself a runner? You may not. But if we look into your evolved biology, you actually are.

Compared to most other species, humans are exceptionally efficient at endurance running. We are one of only a few animals that have the capacity to run extremely far distances, like marathons and ultramarathons. In this week’s video, I share the evolutionary reasons behind such physical feats.

Housekeeping:

If you don’t follow me on Instagram, then you weren’t privy to some news I dropped this week. This is the last week of Evolve.2 content for some time. I’m taking a break from social media for a couple of weeks - which means no Instagram, no YouTube, and no newsletter.

In the meantime, I plan on brainstorming some ideas for when I come back. I want to go even deeper into the topics I discuss and make longer, higher-quality videos. I’ve been putting content out consistently, and I feel I now have the fundamentals down. Time to take it to the next level.

But since I’ll be gone for some time, I’m posting two videos this week… So expect another one tomorrow!

Links to my e-Courses

• The Bare Minimum - FREE

• The Adaptive Scholar - $5

Running is deeply rooted in the human species. Ever since we traded the constraints of the trees for the constraints of the ground, we have developed a rather unique form of locomotion. This is especially true when you compare us to the other primates.

Unlike chimps and gorillas, we are obligate bipeds - meaning we habitually walk on two feet. Whereas chimps and gorillas can only do this for short distances before returning to their knuckle-walking, we can spend all day moving around with an upright posture.

Walking on two feet made us slower than most quadrupeds in Africa, so we had no shot at hunting our prey via sprinting. In response, we evolved behavioral strategies and physical adaptations to compensate. The strategy that came to define our hunting is called persistence hunting.

Persistence Hunting

When you look at the fauna living on the African continent, you are looking at the most competitive arena in nature. Each species is equipped with attributes that optimize it to eat and not be eaten. Lions are powerful and have vicious fangs. Cheetahs have speed for offense and gazelles have speed for defense. Comparatively, humans are pathetic in these respects. Our power, strength, and speed pale in comparison to the vast majority of Africa’s species. 

What we do have is endurance. 

That same African environment is what selected us to become great endurance runners due to the very fact that we are so insufficient with regard to those other attributes. Competing against these species throughout evolution, we could not rely on strength or speed. We needed an alternative means of finding and acquiring food. What we evolved to do is now called persistence hunting and modern hunter-gatherer groups still use it today.

The crux of persistence hunting is running your prey to exhaustion. Although they may be faster than you, if you possess greater endurance, then you will outwork them in the long run - if you can’t beat your prey in a sprint, you have to beat them in a marathon. But is this actually an effective strategy?

Louis Liebenberg’s research suggests that [1]:

This is further corroborated by vast amounts of ethnographic data showing the prominence of persistence hunting cross-culturally in modern times [2]. If this strategy was not adaptive, it would not have persisted into recent years like it has.

Pre-Human Adaptations for Running

Modern humans are born with adaptations for endurance running, but this wasn’t always the case. The earliest hominins (human-like species) looked more like chimpanzees than us, and if you’ve ever seen a chimpanzee try to run, they’re not very efficient. It’s more of a chaotic waddle or gallop than a run. But chimps and the last common ancestor we share with them likely have/had some pre-adaptations that allowed running to take form in our lineage - the hominin lineage. 

According to David Carrier, who formalized this idea of persistence hunting, the following characteristics were present in the primate species from which we evolved and permitted the adoption of running [3]. 

First, these species have sweat glands and reductions in body hair that allow for more efficient heat dissipation during physical activity. Second, their bodies are adapted to arboreal forms of locomotion, which is an easier starting point than walking on all fours to transition to bipedalism (walking on two feet). Third, they are especially good at utilizing fat for muscle energy. Fourth, their omnivorous diets allow for carb-loading, which increases glucose storage.

Born To Run

Bipedalism is likely the first major adaptation that defines human-like locomotion. Evidence of this first appears roughly 6-7 million years ago (MYA) with species like Sahelanthropus tchadensis and Orrorin tugenensis. These species began to show signs of upright posture, such as vertically oriented necks and larger hip joints. Other adaptations in later species include S-shaped spines and foot arches [4].

These species and their immediate successors probably did little more than walk with their new postural structure. They still had long, clumsy toes that were good for grasping tree branches but would get in the way of running. They also still had a little too much body hair, preventing them from staying cool on long runs. Full-blown bipedal running probably didn’t occur until later, because more adaptations were needed.

As time went by, the humans who still possessed those ancestral traits were less successful because they still weren’t strong or powerful, and they also weren’t great runners yet. It was the humans who had slightly shorter toes and slightly less body hair who were at the advantage when it came to outrunning their next meal.

Studies on modern humans have shown that people with shorter toes are biomechanically more efficient at running, making it less metabolically costly [5]. In fact, this is true for running but not walking, which suggests that shorter toes were an adaptation specifically for running. Additionally, the literature suggests that beginning around 2 MYA, certain heat dissipation mechanisms are exaggerated in the human lineage [6]. This includes having more sweat glands, less body hair, and even the ability to anticipate and modify their running pace. 

Think about hunting. The goal is to acquire food for energy. In the world of natural selection, attaining this goal is essential for survival and reproduction. To do it while spending minimal energy is ideal. In the heat of Paleolithic Africa, conserving energy would have been a problem for humans who did not possess the above traits. They perished. Our direct progenitors were those who did have those energetically efficient traits. They were the ones who outran their prey, caught and ate it, and therefore survived another day for another chance to reproduce.

What are the Implications?

Any doctor or health professional worth his or her salt will preach the benefits of endurance training. They will tell you how it improves the health of your heart and lungs; and how it can prevent diseases like diabetes. Rarely will they explain why those benefits exist. The answer is this: endurance running is what kept our species alive and thriving in the hyper-competitive environment of Paleolithic Africa. The selective pressures of this environment forced our ancestors into the endurance niche, whereby running was our first “human” form of subsistence - our first form of work. 

Under these conditions, our DNA was drafted. Natural selection is our architect. DNA is our blueprint.

We do not enter the world as blank slates. Our DNA is coded to anticipate the external world and act as guidance. When the world we experience is not what was anticipated by our DNA, we experience dissonance, tension, and challenge. Accordingly, the world we live in today does not require us to run for survival anymore. We are becoming sedentary creatures, but the environments that shaped our cardiovascular systems and metabolisms were environments of physical activity. 

As a result, we are not adapted to the modern world. As we fail to engage in physical activity, especially endurance work, our cardiovascular systems begin to malfunction and we’re experiencing high rates of disease as a result. To combat this, we must react appropriately. We must act like the humans of our past. We must (re)act.

References:

[1] Liebenberg, L. 2006. “Persistence Hunting by Modern Hunter‐Gatherers.” Current Anthropology 47(6):1017-1026.

[2] Lieberman, D., et al. 2020. “Running in Tarahumara (Rarámuri) Culture: Persistence Hunting, Footracing, Dancing, Work, and the Fallacy of the Athletic Savage.” Current Anthropology 61(3):356-379.

[3] Carrier, D. 1984. “The Energetic Paradox of Human Running and Hominid Evolution.” Current Anthropology 25(4):483-495.

[4] Lieberman, Daniel E. 2014. The Story of the Human Body: Evolution, Health and Disease. New York, NY: Vintage Books.

[5] Rolian, C., et al. 2009. “Walking, running and the evolution of short toes in humans.” Journal of Experimental Biology 212(Pt 5):713-721.

[6] Bramble, D. and Lieberman, D. 2004. “Endurance running and the evolution of Homo.” Nature 432:345–352; Marino, F. 2008. “The evolutionary basis of thermoregulation and exercise performance.” Medicine and Sports Science 53:1-13.

Fit Fuel Song Suggestion

The Fit Fuel song suggestions are hand-picked by yours truly to elicit the motivation (and possibly aggression) needed to initiate or persist through a grueling workout. They consist of heavy, brutal guitar riffs and gruesomely guttural vocals. Additionally, I timestamp what I believe to be the best riff of the song - one that will kick your nervous system into overdrive when approaching a personal record (PR).