Though many of us live sedentary, couch-potato lives, our not-so-distant ancestors were high-performing endurance athletes. Being hunters and gathers, they traversed large stretches of land and led extremely active lifestyles. For them, it was a matter of survival.
Researchers from the University of Arizona wanted to see if evolution pushed people to exercise through reward pathways. Spoiler alert: The answer is yes.
If you’ve ever engaged in cardio at a high level of intensity, then you’ve probably experienced the infamous runner’s high. This very real phenomenon is caused by endocanabinoid signalling in the so-called reward centers of the brain. It makes us feel good. Maybe even great.
But is this runner’s high feeling exclusive to animals – like humans and dogs – that are built to be endurance athletes? Or do less active animals also experience this high?
Researchers used blood samples to compare endocanabinoid levels between humans and dogs to less-active ferrets. According to the research, ferrets did not experience elevated endocanabinoid levels after exercise – or the pleasures that accompanies it.
In other words, evolution used the endocanabinoid system to motivate endurance exercise in humans, dogs and other active species. It’s a remarkably clever way to motivate exercise for those species whose survival requires it.
Though the runner’s high can certainly help motivate individuals to stay fit, it’s not something that inactive people will necessarily experience – at least, right away. According to one researcher, “Inactive people may not be fit enough to hit the exercise intensity that leads to this sort of rewarding sensation.” But it’s definitely something to build up to.