Is marijuana bad for the heart? What you need to know

Women are more likely to have atypical heart attack symptoms (along with chest pain), like shortness of breath, nausea or vomiting and back or jaw pain. Fotolia

Women are more likely to have atypical heart attack symptoms (along with chest pain), like shortness of breath, nausea or vomiting and back or jaw pain. SOURCE: Csaba Deli/Fotolia


Is pot bad for your heart? While some advocates claim cannabis is harmless, others say it’s damaging one of the most important parts of our body: the cardiovascular system. As cannabis use increases in popularity, both recreationally and medicinally, it is becoming increasingly important to understand these potential effects.

Scientists agree on a few notable effects cannabis has on the heart. For example, the research is consistent that THC can increase heart rate, affect blood pressure and decrease the amount of exercise it takes to induce angina (chest pains). For those already at risk for cardiac complications, there is concern these effects could trigger dangerous cardiac events. While there isn’t much research on this, there is limited evidence of an association between cannabis use and strokes or the triggering of heart attacks.

Researchers from St. Luke’s University did connect cannabis use to an increased risk of a rare condition called takotsubo, where the heart’s muscles are suddenly (usually temporarily) weakened, reducing the heart’s ability to pump blood. While takotsubo usually affects older women, cannabis using takotsubo sufferers were more likely to be young men. Still, lead researcher Amitoj Singh explains that despite the young, healthy profiles of cannabis using takotsubo patients, they had “higher rates of cardiac arrest, acute stroke and need for implantation of defibrillators in comparison to their older, sicker (with more medical comorbidities) non-marijuana counterparts.” Singh was careful to note that this study only showed an association, not causation, saying “to confirm what we find, we need randomized studies.”

Is cannabis helpful or harmful? It may be both.

There have also been a few reports of healthy, young patients having fatal cardiac events with THC in their system but no other medications or drugs. While unnerving, these reports are extremely rare, and tell us very little. In the large scale, longitudinal studies researchers have not been able to show any statistical tie between cannabis use and increased cardiovascular mortality.

Despite these potential risks, research also shows cannabis can benefit our heart. Cannabis is associated with a lowered risk of obesity; and since obesity has been shown to contribute to heart disease, experts suggest this may lower the risk of heart disease as well. THC has been shown to reduce damage from heart attacks, while CBD has anantiarrhythmic effect. And there is limited evidence that cannabis use decreases the risk of diabetes.

Cannabis can also help the heart as an anti-inflammatory agent. In a recent 2017 study, researchers from the American Heart Association concluded that cannabis is protective against peripheral vascular disease, preventing the narrowing and spasming of blood vessels with its anti-inflammatory properties.

Is cannabis helpful or harmful? It may be both. While more rigorous controlled studies are needed to fully understand the risks and benefits, it’s clear that cannabis is a powerful substance with the power to affect our cardiovascular system. Like most medications, it might be helpful for some conditions and harmful for others. Patients considering using cannabis should talk to a doctor about whether it is a safe option for them.

[Emily Earlenbaugh is a cannabis patient consultant and wellness researcher. She is the author of the online course ‘The Mindful Guide to Cannabis’ and has a doctorate in philosophy of science from UC Davis.]