Africa is the setting for the long dawn of human history and our Darwinian evolutionary sequence. Four million years ago, apelike creatures named Autralopithecus walked upright on that continent. They were an intermediate species, between apes and human. Two million years ago, the first creatures to be classified as part of the human species— Homo erectus—evolved in Africa. The Lower Paleolithic era took place somewhere around one hundred thousand years ago, as Homo sapiens—how we are classified—replaced Homo erectus.
Thirty thousand years ago, there was a seemingly endless supply of animal life and edible plants as the early human families migrated with the game herds and hunted what they needed to survive. When they weren't hunting, they watched the stars, told stories around the fire, and painted their dreams on the walls of caves. High levels of intelligence were required to make tools and find prey. Our early human ancestors used endurance to chase prey to exhaustion. This worked for scavenging too. The premise is that in the savannah ancestors would compete with hyenas—also good long-distance runners—to get to an animal carcass. The theory tells the story behind our springy Achilles tendons, hairlessness, and ability to sweat.
Semicircular canals in the inner ear also help us balance as we run. Our modern adaptations of ancient wirings are still at work.
The good thing is that evolution took into account that humans need a little extra motivation across the hot desert. You have probably at some point in your life experienced what's widely described as "runner's high" or a flow of endorphins during aerobic exercise. Exertion kicks in our brain's reward centers, so not only are we hardwired with the anatomy to be active, we're hardwired to enjoy it!
Daniel Lieberman and Dennis Bramble have written a great piece on humans' relationship with running, called " The Evolution of Marathon Running." It's well worth a read, as is David Raichlen's article " Wired to Run," published in the Journal of Experimental Biology.
Have you ever experienced a runner's high? Share your experiences in the comments section!