The Brain Effects of Runner’s High

“Runner’s High” might not be what you think!

Anyone who has ever deemed themselves a runner has probably experienced an interesting feeling known as Runner’s High. It’s been defined as a feeling of euphoria coupled with reduced anxiety and a lessened ability to feel pain.

The New York Times recently reported that, “In surveys and studies of experienced distance runners, most report developing a mellow runner’s high at least sometimes. The experience typically is characterized by loose-limbed blissfulness and a shedding of anxiety and unease after half an hour or so of striding. In the 1980s, exercise scientists started attributing this buzz to endorphins, after noticing that blood levels of the natural painkillers rise in people’s bloodstreams when they run.”

And it’s typically been associated with endorphins and opioid peptides thought to elevate mood that are released during and after the run.

Until now.

According to an article published by Scientific American, German researchers have shown the brain’s endocannabinoid system—the same one affected by marijuana’s Δ9-tetrahydrocannabinol (THC)—may also play a role in producing runner’s high!

Endorphins can’t pass through the blood-brain barrier, so they alone cannot create the “high” that runner’s experience. It also is unlikely that the brain itself produces more endorphins during exercise, according to animal studies.

However, a lipid-soluble endocannabinoid called anandamide —also found at high levels in people’s blood after running —CAN travel from the blood into the brain, where it can trigger a high.

In a recent study published in Psychoneuroendocrinology, Dr. Fuss and his colleagues set out test this understanding in humans. Recruiting 63 experienced runners, male and female. The volunteers ran for 45 minutes and, on a separate day, walked for the same amount of time. After each session, the scientists drew blood and performed psychological tests. They also asked the volunteers whether they thought they had experienced a runner’s high.

Most said yes, they had felt buzzed during the run, but not the walk, with no differences between the naloxone and placebo groups. All showed increases, too, in their blood levels of endocannabinoids after running and equivalent changes in their emotional states. Their euphoria after running was greater and their anxiety less, even if their endorphin system had been inactivated.

Taken as a whole, these findings are a blow to endorphins’ image. “In combination with our research in mice,” Dr. Fuss says, “these new data rule out a major role for endorphins” in the runner’s high.

That said, there is no research that investigates people’s behavior after running to compare it to the behavior of others whose high is attained through other means.

Well, not yet!