Runners enjoyed their workouts more after using cannabis, but physically floundered

Using cannabis before a run can make those mundane miles more enjoyable, but may make them feel harder to complete, new research suggests.

In a small study of 42 regular runners in Colorado, where the sale of recreational cannabis has been legal since 2014, study participants reported experiencing a mood boost and greater enjoyment during a 30-minute treadmill workout when they had smoked or vaporized cannabis beforehand. However, on average, participants said that they had to put a lot more effort into running after using cannabis, compared to when they ran sober.

"It is pretty clear from our research that cannabis is not a performance enhancing drug," Angela Bryan, co-senior study author and a professor of psychology and neuroscience at the University of Colorado Boulder, said in a statement.

The authors of the study, published Dec. 26 in the journal Sports Medicine, were inspired by earlier research that suggested runners regularly use cannabis while exercising in states where recreational use of the drug is legal, such as Colorado, California and Nevada.

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While cannabis won't turn a regular runner into an elite athlete, it could encourage people who are less likely to exercise to get motivated to work out, the authors argue.

"We have an epidemic of sedentary lifestyle in this country, and we need new tools to try to get people to move their bodies in ways that are enjoyable," Bryan said in the statement. "If cannabis is one of those tools, we need to explore it, keeping in mind both the harms and the benefits."

Cannabis contains substances called cannabinoids, which include tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is largely responsible for the characteristic "high" associated with weed, in part because it binds to brain receptors involved in the reward system and feelings of pleasure. CBD does not produce a high but has been studied for its potential medicinal properties.

In the new study, the researchers took baseline fitness measurements of the runners during a 15-minute treadmill test and also had them complete a survey about their prior cannabis use, exercise regimes and attitudes towards doing both activities simultaneously. Then, they asked the runners to pick up 1 gram (0.035 ounces) of cannabis from a dispensary; each participant was told to get a strain that mainly contained either CBD or THC.

Participants used their assigned product at home and were then driven to an exercise facility, where they completed a survey before and after running on a treadmill for 30 minutes. The questions probed the participants' moods, their pain levels and how difficult they found the run. Two days later, the participants repeated this process but without the cannabis.

Every runner reported enjoying their workout more when they had used cannabis beforehand. That finding aligns with research that suggests endocannabinoids — body-made substances that chemically resemble compounds like THC and CBD — are involved in producing a "runner's high," the short bursts of euphoria that some people experience during or after exercise. Using cannabis before a run may therefore enhance that runner's high, the authors said.

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However, the people who inhaled the THC-dominant cannabis strains noticed less of an increase in the enjoyment of their run than the CBD group did. In addition, they felt much more effort was needed to complete their workout after inhaling the drug. This could be partly because THC increases heart rate, Bryan said in the statement.

The new study had several limitations. For instance, it didn't include a group who used a placebo drug instead of cannabis, as a point of comparison. In addition, all of the participants had previously used cannabis while exercising, so the fact that they volunteered suggests they likely had a good experience in the past, potentially biasing the results.

Nevertheless, the study authors said this research is a step toward better understanding how cannabis affects exercise.

"Continued research into the impact of cannabis on the subjective experience of exercise — both positive and negative — is critical," they wrote in the paper.

This article is for informational purposes only and is not meant to offer medical advice.

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