Runners High: What are Cannabinoids?

If you regularly run long-distances, you may have experienced the so-called "runnerís high," typically defined by characteristics including euphoria, sedation, and reduced anxiety and pain sensitivityófeelings can make a 10-mile run feel less like a slog and more like a great way to spend your afternoon.

Even if you're not a runner, you may have heard that the runner's high is attributed to hormones called endorphins. But a new study suggests otherwise.

How the Runner's High Works

Endorphins are actually opioid peptides, a type of molecule released by the body during exercise. Exactly how the endorphins were believed to spark the runner's high was not clearly understood, so a group of scientists tried to learn more about it. And what they discovered may surprise you.

The researchers determined that when people go running, in addition to endorphins, endocannabinoids are also released in the bloodstream. Endocannabinoids are naturally occurring cannabis-like (or marijuana-like) substances that are produced by the body.

In the study, the researchers ran various tests on mice, and tried blocking the endorphins and the endocannabinoids to see what happened. When their endorphins were blocked, mice running on a wheel for an extended period of time still experienced the runner's high. But when the endocannabinoids were blocked, the runnerís high was prevented, explains study lead author Johannes Fuss, MD, who is affiliated with the Institute for Sex Research and Forensic Psychiatry at the University of Hamburg Medical Center.

The results suggest that it's the endocannabinoid system (a neurochemical system that regulates different functions in the brain and body and releases the endocannabinoids), not endorphins, that plays a major role in achieving a runnerís high.

"It was a common saying for runners to refer to endorphin-release after running and relate it to their emotional benefit," Fuss says. "We have shown that this popular belief may be scientifically wrong, and [that] endocannabinoids are indeed responsible for a runnerís high."

The Next Step

"In the future, we plan to study which brain regions are involved in the runner's high, and how they are influenced by endocannabinoids," the researcher says. "So far we donít know what exactly has to happen [to trigger a] runnerís high to appear in humans, because it seems to be an ephemeral [brief] phenomenon. It seems to depend on the individual."

And here's some really interesting news: the runner's high may not even require running: Some people can get the benefits with fast walkingóthe time and distance that's required to trigger the reaction seems to vary from person to person.

Regardless of what it takes to achieve a runnerís high, the results not only feel good, but also bring some important health benefits, including pain and anxiety reduction. This is on top of the fact that regular exercise, like running, also reduces the risk of a number of serious conditions, such as heart problems, stroke, diabetes, Alzheimerís Disease, and depression. So lace up your sneakers, and start chasing that high!

Johannes Fuss, MD, reviewed this article.

Sources

Fuss, Johannes, Institute for Sex Research and Forensic Psychiatry, University of Hamburg Medical Center. Email interview, November 2, 2015.

Fuss, Johannes, et al."A Runnerís High Depends on Cannabinoid Receptors in Mice." Proceedings of the National Academy of Sciences of the United States of America 2015. Vo.112 (42): 13105-13108.