Hormone Affects “Runner’s High”

Leptin, the satiety hormone produced by fat, affects neuronal signaling in the mouse brain; interference with this pathway can influence the rewarding effects of running in the animals.

Sep 2, 2015
Tracy Vence

WIKIMEDIA, DATABASE CENTER FOR LIFE SCIENCESThe rewarding feelings of running—often called “runner’s high”—are in part modulated by a hormone that affects signaling in the brain, according to a mouse study published in Cell Metabolism this week (September 1). Specifically, knockout of a receptor for the adipose-produced leptin, which inhibits hunger, led mice to nearly double the amount of time spent running compared with their wild-type counterparts.

“Based on these findings, we think that a fall in leptin levels increases motivation for physical activity as a means to enhance exploration and the pursuit of food,” study coauthor Stephanie Fulton, an associate professor of nutrition at the University of Montreal, said in a statement.

In previous studies, reduced levels of leptin have been associated with high endurance in people. The hormone is thought to also play a role in anorexia.

“Our study also suggests that people with lower fat-adjusted leptin levels, such as high-performance marathon runners, could potentially be more susceptible to the rewarding effects of running and thus possibly more inclined to exercise,” noted Fulton, adding that the brain-signaling disruption she and her colleagues observed in knockout mice “could potentially underlie the hyperactivity associated with anorexia.”