Runner’s high is a real thing. Chances are, if you have ever finished exercising and you “feel good,” or if you feel better than you did before, you were probably experiencing runner’s high. If you are interested in learning more about runner’s high, there are many articles available, including some on this site.

A study done at the University of Arizona might suggest that the reason why we experience these feel good feelings is because of evolution. In the study, David Raichlen explains how our hunter/gatherer predecessors have always been endurance athletes. He believes that aerobic activity has played a role in the evolution of many different systems in our body, and because of this, we are able to experience those “feel good” symptoms.

Raichlen suggests that not everyone can “feel good” after exercising. Runner’s high occurs because exercise triggers the endocanabinoid, and this signals the “reward centres” of the brain. There isn’t too much known about endocanabinoids and their role in aerobic activity, so Raichlen decided to do a study on how they affect aerobically active mammals versus inactive mammals. He did this study to determine whether it was evolution that helped us want to become aerobically active people.

Raichlen’s study involved dogs, humans, and a low activity animal — ferrets. The participants were to walk on a treadmill, and their blood samples were collected in order to measure the amount of endocanabinoids pre and post exercise. In general, they found that the naturally active test subjects had much higher concentrations of endocanabinoid than the inactive subjects (the ferrets). That being said, the study seems to suggest that lower-active mammals are less affected by exercise, so they do not get as much of that “feel good” symptom that others do. This suggests that natural selection used the endocanabinoid system to affect how humans and other mammals exercise.

So, if you are not really a physically active person, you might not know what I’m referring to in terms of “feeling good” after exercising; however, do not worry, as you can build up the ability to be affected by these chemical triggers. All you have to do is to start being more proactive with your exercising!