Researchers suggest that humans who participate in aerobic exercises, or rhythmic and continous exercise, may produce the addicting chemicals that helped turn humans into long-distance runners.
Long-distance running for early humans may have provided them with a method to hunt and exhaust prey without feeling pain. Yet, meat is not the only benefit of long-distance running.
According to David Raichlen, a University of Arizona researcher and anthropologist, humans are “wired to run.”
“Wired to run meaning that our brains probably have been sort of rewired from an evolutionary sense to encourage these running and high aerobic activity behaviors,” Raichlen says in an interview with NPR.
According to Raichlen, the reward from being “wired to run,” comes in the form of a high—the runner’s high. Raichlen published his research in the Journal of Experimental Biology, in which he tested his theory on animals.
“Humans report a wide range of neurobiological rewards following moderate and intense aerobic activity, popularly referred to as the ‘runner’s high’, which may function to encourage habitual aerobic exercise,” Raichlen reported in his study.
Endorphins, or brain chemicals known as neurotransmitters, function to transmit chemical signals within the nervous system. They are produced during stress, pain, excitement and exercise. When these feelings are released, endorphins trigger a euphoric response. Scientists and doctors have long debated whether endorphins are produced during long and continuous exercise.
The additive nature of achieving a runner’s high and producing endorphins has often been described as the same behavior drug-seeking patient’s exhibit.
Yet, it’s not just endorphins that are produced during a runner’s high. When people exercise continously or aerobically, their bodies can produce cannabinoids, the same type of chemicals that are found in marijuana.
“A neurobiological reward for endurance exercise may explain why humans and other cursorial mammals habitually engage in aerobic exercise despite the higher associated energy costs and injury risks,” Raichlen said in his study.
He argues that his findings are not conclusive, however, and he will have to test more animals.
The next time someone says they may be “addicted” to exercise, maybe they’re telling you the truth.