University of California study finds cannabis use linked to fewer premature heartbeats

A study conducted by researchers at the University of California, San Francisco, has revealed a counterintuitive relationship between cannabis use and heart rhythm. In the MARY-JANE trial, habitual cannabis users experienced approximately 9 percent fewer premature heartbeats on days they inhaled the substance compared to days they abstained.

The reduction was primarily driven by a 10 percent decline in premature atrial contractions, while premature ventricular contractions showed no significant change. Participants in the study, totaling approximately 100 to 108 adults, wore continuous electrocardiographic monitors, activity trackers, and glucose monitors over a 14-day period. The study utilized a crossover design where participants were randomly assigned to either inhale cannabis or abstain on any given day, allowing them to serve as their own control.

Researchers noted that these findings contradict previous observational data and their own initial hypotheses, which expected cannabis to increase irregular heartbeats. Senior author Gregory Marcus emphasized the importance of randomized controlled trials in challenging existing assumptions. Despite the findings, researchers cautioned that these results should not be used to influence medical or behavioral decisions regarding cannabis consumption.