With cannabis now legalized in large swaths of the country, people are using it at higher rates than ever before. That means there’s a pressing need for more data on how the formerly illicit substance affects our bodies. It also means that performing that research is a lot easier—just put up some flyers, post on social media, and wait for the stoners to pour in. That’s what a team of researchers from the University of California San Francisco recently did for a study on how cannabis affects our hearts.
The team recruited more than 100 regular cannabis users (both smokers and vapers) willing to abstain from their preferred drug for at least two grueling, consecutive days. They were outfitted with a monitor that recorded their heartbeat, activity, sleep, and glucose. Each day, they received a text message letting them know if they could partake or not and pressed a button on their heart monitors when they took their first toke.
Surprisingly, the researchers found that cannabis use was associated with a 9 percent drop in the incidence of extra or early heartbeats (also called cardiac ectopy), a common phenomena that’s usually no cause for concern. The reduction was caused by a decrease in heartbeats that started in the atrial chamber. While usually harmless, an increase in frequency in these premature atrial contractions can send someone into atrial fibrillation. They didn’t find any change in early beats originating in the ventral chamber (which can be a warning of impending heart failure).
Read more: “The Science of Your Weed’s Stank”
“We were surprised by the results because they contradicted our original hypothesis,” study author Gregory Marcus said in a statement. “That’s why randomized trials are so important. When the data challenge our expectations, our job as scientists is to understand them, not ignore them.”
Also somewhat surprising, inhaling cannabis didn’t change the participants’ daily steps, sleep, and glucose levels—they were just as active (or inactive) regardless of whether they’d taken the drug.
Does that mean weed is heart healthy? Maybe not. The study was designed to measure acute effects of cannabis among regular users and can’t speak to the long-term effects, researchers say. A smaller study published last year found that people who smoked or even ingested cannabis for five to 10 years showed reduced blood vessel function, similar to tobacco smokers.
“The overall health effects of inhaled cannabis may still be net negative, but these findings suggest there may be something about cannabis that can teach us more about the biological mechanisms that produce premature atrial contractions,” Marcus explained. “That knowledge could eventually lead to new approaches for preventing or treating abnormal heart rhythms.”
To paraphrase the great poet Homer Simpson, “Cannabis: the cause of and solution to all of life’s problems.” 
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Lead image: Kayley / Adobe Stock
