Humans run. Whether it’s a short sprint between your car and a restaurant during a downpour, a 5K — or 26.2 miles and beyond, there’s no question that everyone runs. But are we supposed to? Despite controversial claims that too much exercise can be harmful, the vast majority of evidence shows that exercise in general, and running in particular, is highly beneficial.
So what’s going on here? Can our bodies handle running, or are we slowly destroying our bodies? Are humans really born to run or not? To try to find some answers, we asked Daniel Lieberman, PhD, an avid runner and professor of human evolutionary biology at Harvard, where he specializes in the biology and evolution of human physical activity (which includes running).
How did you end up studying the evolution of running? It’s such a specific niche.
Lieberman: I’ve always been interested in why humans are they way that they are, but I got interested in the topic of running when I was a student and Dave Carrier published a paper on this topic in 1984. After reading it, I had a conversation with a professor of mine who, frankly, thought it was hogwash. He subscribed to the idea that humans are slow and inefficient and, thus, that it’s silly to think that we have evolved to run. But the idea persisted for me for years and one day it sort of came into focus. I was a postdoctoral fellow, and I was doing a locomotion experiment on pigs of all animals, when Dennis [Bramble] came into the lab and pointed out that the pig couldn’t hold his head still while it was running. That sparked research into the difference between bipedal and four-legged animals, and eventually Dennis and I published [the review] “Born to Run.”
In that review, you discuss your findings that indicate that humans have, in fact, evolved to run. What are some of the biological features that point to this evolution?
Lieberman: There’s so much evidence, it’s hard to know where to start, but the features that make us good at running are literally from head to toe. For one, humans have all kinds of anatomical features that are unique to us and animals that do lots of running, like short toes, an enlarged gluteus maximus, elongated Achilles tendons and metabolisms that are able to handle endurance running. Endurance running is a tradeoff between speed and power for which we’ve clearly adapted. Other features include a twisty waist, the ability to keep our heads from jiggling when running, the lack of fur and the presence of a lot of sweat glands.
In addition to anatomical features, we also need to consider our performance abilities as primates. When we think about human running, we often compare ourselves to horses and dogs and other species adapted for running, but we are actually primates and, when you compare us to other primates, we stand out. There are no other primates that can run long distances. That said, our ancestors certainly weren’t running 26.2 miles.
Speaking of our ancestors, what do you think caused us to evolve and adapt this ability?
Lieberman: No one has really been able to come up with a better answer other than hunting and scavenging, which is part of the hunting and gathering way of life — and I haven’t been able to, either. I’m sure we sometimes had to sprint to get away from an animal that was chasing us, but I doubt our ancestors were ever able to sprint to hunt. Professional runners like Usain Bolt can run 10.4 meters a second for less than 10–20 seconds, but most animals we hunted could run twice as fast for more than 4 minutes. People certainly didn’t run for fun or for health, and they didn’t do it for warfare either; that kind of violence didn’t evolve until very recently.
Have humans evolved for a particular style of running? Sprinting versus long distance for example?
Lieberman: Yes. Humans are really evolved for endurance, not speed. You’ll notice this if you go to a marathon and hang around the finish line for a while. Of course the first few people that cross the line are exceptional, but if you stay for a few hours, you’ll see that anyone can run a marathon. All kinds of people cross the finish line — old, young, big, small. Pretty much anyone, unless they’re seriously injured or disabled, can train for and run a marathon.
That said, we tend to focus on the marathon, but that’s not necessarily what we evolved to run. Our capabilities far exceed what we actually need to do. We’ve evolved to run something more like a half-marathon — and slowly: 10-minute miles perhaps, interspersed with lots of walking.
GEAR UP FOR YOUR NEXT RUN