Runner's High

by Adam Qu

This passage from A Separate Peace, by John Knowles, perfectly captures the short-term feeling of euphoria experienced by many during or after long-term, rhythmic physical activities, like running. This sensation, commonly known as runner’s high, has been described as the “feeling of being invincible, a reduced state of discomfort or pain, and even a loss in sense of time” (WebMD). Overtime, the cause of runner’s high has undergone some debate and revision. A study conducted in the 1980s found that the level of endorphins, a morphine-like chemical produced by the body that helps relieve pain, in the bloodstream increased after prolonged exercise (NY Times). This explanation makes sense, as physical exercise can cause pain and discomfort and the endorphins could relieve that pain. However, the problem with this reasoning is the size of endorphins, which are too big to pass through the blood-brain barrier, a highly selective membrane that prevents most blood-borne substances from entering the brain (SciShow). It is reasonable to conclude from this fact that endorphins most likely do not cause the euphoric feelings associated with runner’s high since they cannot interact with the brain, where these feelings would originate. Additionally, some studies have chemically blocked the effects of endorphins but the subjects (mice) still experienced a high (WebMD).

Researchers now believe that runner’s high is caused by a type of neurotransmitter in the brain called an endocannabinoid. Endocannabinoids interact with the same systems of the brain as compounds in the drug cannabis, or marijuana, but are made naturally by the body. In 2015, a study conducted at the Central Institute of Mental Health at the University of Heidelberg medical school in Mannheim, Germany, showed that mice produced increased amounts of anandamide, a type of endocannabinoid, after running on a wheel compared to those that did not (SciShow). To test the pain relief of runner’s high, the mice were placed on a hot plate to cause pain. Mice who had been running on the wheels took longer to show signs of agitation from the heat, such as “licking hind paws or jumping” (Mice). To ensure that endorphins were not playing a role in the mice’s response, some of the running mice were given drugs to block endorphins from binding to receptors but they still acted calmer than mice who had not run. Other mice who had run that had anandamide blocked instead were as sensitive and agitated by the hot plate as non-runners (Mice). Studies with humans have also found increased endocannabinoid levels after running, but the small sample sizes of these studies make it uncertain that endocannabinoids are the definite reason for a runner’s high (SciShow).

While the biological cause for a high is still not completely established, there has been agreement on the way to obtain it. Getting a runner’s high doesn’t necessarily have to be through running. Many non-runner athletes have experienced a high from other activities such as swimming, rowing, cycling, and weightlifting. These athletics all have something in common: repetition. Another factor in achieving a high is time; continued exercise for 30 minutes or more increase the chances of attaining a high (WebMD). Whether or not a high is achieved, however, there is no doubt about the long-term health benefits of regular exercise.