Study outlines potential risks, benefits of using marijuana

A new study by the American Heart Association has outlined both the risks and potential benefits associated with the use of marijuana.

Dr. Martha Gulati, chief of cardiology for the University of Arizona College of Medicine and editor in chief of the American College of Cardiology’s website, CardioSmart.org, says it’s an important overview.

“It’s not guidelines per se, but it’s a statement on what knowledge we have to date relating marijuana to cardiovascular health. Because we often do get asked this question in patients who have heart disease if it’s OK for them to use marijuana.”

Throughout the study, the authors emphasize that conclusive evidence on how marijuana affects the heart is lacking. But they note that tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, may be dangerous for certain individuals.

“[THC] stimulates the sympathetic nervous system while inhibiting the parasympathetic nervous system; increases heart rate, myocardial oxygen demand, supine blood pressure, and platelet activation; and is associated with endothelial dysfunction and oxidative stress.”

“When people use marijuana, it can increase their heart rate,” says Gulati. “So it causes something called tachycardia, which is just a fast heart rate, but it also can make them at more risk of going into an arrhythmia [the heart beating too fast or too slow.”

A 2020 post from Harvard Medical School adds that marijuana — likely due to the aforementioned effects — may increase the risk of heart attack and stroke as well.

“The risk of heart attack is several times higher in the hour after smoking marijuana than it would be normally, research suggests,” Harvard writes. “And one survey suggests that smoking marijuana may raise the risk of a stroke.”

The authors make a point to clarify that while the drug may come with risks, there are many conditions for which it has shown to be an effective treatment. Among those listed are epilepsy, multiple sclerosis, wasting syndrome, opioid addiction, glaucoma, anxiety, depression, and Crohn’s disease, hepatitis C, Huntington’s disease and Parkinson’s disease.