Study examines effects of cannabis on exercise

The 2021 Summer Olympics sparked controversy around cannabis and athletic performance when sprinter Sha’Carri Richardson was suspended for testing positive for marijuana, a banned substance under World Anti-Doping Agency rules. But, to date, little scientific research has been conducted on whether and how tetrahydrocannabinol (THC) and cannabidiol (CBD)––the two primary active ingredients in marijuana––hinder or help athletic performance. 

Now, a new, first-of-its-kind study out of CU Boulder hopes to shed some light on how legal market cannabis impacts the experience of exercise.

“Cannabis is often associated with a decrease in motivation. But at the same time, we are seeing an increasing number of anecdotal reports of people using it in combination with everything from golfing and yoga to snowboarding and running,” said Laurel Gibson, a Ph.D. student in the Department of Psychology and Neuroscience and principal investigator of the study.

The SPACE study (Study on Physical Activity and Cannabis Effects) is actively recruiting paid adult volunteers who already mix cannabis and exercise for a study involving three sessions. One they will take a baseline cognitive and physical test and are assigned to use either a CBD- or THC-dominant strain of cannabis; a follow-up where they work out sober and answer questions about their workout experience; and a third where they do the same, but use the strain they were assigned beforehand.   

Federal law prohibits the possession or distribution of marijuana on college campuses, so subjects take it at home before a researcher picks them up and drives them to the lab. As a precautionary measure, the runner wears a safety belt on the treadmill.

Previous studies suggest that it is not endorphins that are responsible for the famous “runner’s high” but rather endogenous cannabinoids, naturally produced cannabinoid-like brain chemicals that kick in after a period of exercise, binding to receptors in the brain to make people euphoric and alert. Gibson hopes this study will shed light on whether THC or CBD activate this endocannabinoid system in a way that mimics the runner’s high.

Cannabis has also been shown to have anti-inflammatory and analgesic effects. 

“If cannabis could ease pain and inflammation, helping older adults to be more active, that could be a real benefit,” said Angela Bryan, a professor of psychology and neuroscience at CU Boulder.

The researchers will also assess how the known negative effects associated with cannabis, including paranoia, confusion and anxiety, might influence exercise.

Ultimately, they hope their findings can help inform discussions from doctors’ offices to the governing bodies of sport, which will soon be re-evaluating whether marijuana should remain listed as a “banned substance.”