Most Americans don’t get anywhere near enough exercise — for all kinds of reasons. Some researchers have wondered whether a rise in the use of marijuana is one of them.
“The stereotype is the kid on the couch eating Doritos, not being physically active,” says Angela Bryan, a professor of psychology and neuroscience at the University of Colorado Boulder. As marijuana is becoming legalized in more states across the country, “if that was the impact of cannabis on physical activity, that [would be] a big problem.”
There isn’t much scientific literature on the relationship between cannabis and exercise. But some research suggests that people who use marijuana actually tend to have lower body mass indexes and risks for obesity than people who don’t use it, and a 2015 review article from Bryan’s lab found that cannabis is linked to greater feelings of motivation and enjoyment about exercise, potentially by activating brain pathways involved in feelings of reward and pain response.
Now, in new research published in Frontiers in Public Health, Bryan and her colleagues found that many people do use weed before or after their workouts — and that those who do actually tend to exercise more than the average American.
The researchers gave a survey to 600 adult marijuana users living in states where the drug is legal, including Colorado, California, Nevada, Oregon and Washington. It included questions about cannabis use and exercise, including when people used the drug, whether they felt it affected their workouts and how they thought it influenced exercise motivation and recovery.
Bryan says she was “pretty shocked” at the results. More than 80% of respondents said they used cannabis within an hour of starting to exercise or within four hours of ending a workout. (Using marijuana after exercise was slightly more common than using it before a workout, according to the survey.)
Many people reported that pot motivated them to work out and helped them enjoy exercise more. People who said they used cannabis either shortly before or after exercise actually got more physical activity than users who said they didn’t mix weed and workouts — more than 2.5 hours per week, compared to less than two hours per week.
“One of the barriers to physical activity is that people say, ‘I don’t like it. It’s boring. It feels bad. I don’t want to do it,’” Bryan says. “If, for some people, cannabis is helping them to enjoy the activity more,” that relationship is worth further study.
But the preliminary research comes with caveats — and cautions. “I certainly am not going to tell anybody to start smoking cannabis so they’ll start exercising,” Bryan says. It’s not known whether the relationship is causal, for one, and using the drug as a workout aid potentially comes with safety risks.
Cannabis can disrupt balance and motor function and elevate heart rate, Bryan says. While those side effects may be fine before lower-impact exercise, Bryan says they could be dangerous before high-intensity workouts or those that require lots of coordination.
The risks are likely lower for those who use pot after working out, especially since both THC and CBD, two compounds in cannabis, have been shown to lower inflammation and help manage pain. But there’s still a lot experts don’t know about the health effects of cannabis. While some studies have found health benefits associated with marijuana, including better mental health, pain relief and even higher sperm counts, others suggest it may come with risksincluding cognitive and cardiovascular strain.
Another reason to take the findings with a grain of salt: people living in states where marijuana has been legalized, which the study exclusively focused on, happen to be some of the most physically active in the country, so it makes sense that cannabis users there would get a lot of exercise. If people do both regularly, these activities may sometimes overlap — so it’s not possible to conclude that the results would be the same for every cannabis user in the U.S., or to make claims about the drug’s ability to inspire exercise, Bryan says.
More research, with more people, is needed in other parts of the country, though future studies will hinge on marijuana’s legality in other regions. Despite the outstanding questions, Bryan says the study achieves at least one important milestone: It questions outdated stereotypes about people who use marijuana.
“It doesn’t seem like the lazy stoner stereotype is really entirely correct,” she says. “You actually can be quite physically active and use cannabis.”