Updated on June 4, 2021.
Medical content reviewed by Dr. Joseph Rosado, MD, M.B.A, Chief Medical Officer
Hey there, your cardiologist called—and gave us a list of ten things they want you to know about your heart health and marijuana.
While marijuana remains a schedule I substance under federal law—which limits its availability for research purposes—experts say the full picture of its health benefits (or harm) on your most important of organs remains only modest and incomplete at best. Far more rigorous, double-blind clinical trials are needed to untangle how marijuana affects your heart and how cardiovascular patients can, or even should, use cannabis.
So in honor of Heart Health Month (February), here’s what we know, and don’t, about your cardiovascular health and cannabis.
Marijuana can either raise, or lower, your blood pressure and heart rate
What seems like a straightforward physiological question—whether or not marijuana raises or lowers your blood pressure—is actually pretty complex. Cannabinoids like THC work to expand your blood vessels, so blood pressure naturally lowers (particularly if it was already high). But as your heart senses these changes in pressure, it begins to pump faster, causing an increase in heart rate. This “bidirectional” (meaning both directions) interaction with the cardiovascular system can independently raise or lower both heart rate and pressure, depending on a host of factors such as: the specific cannabis strain used, the ingestion method, how long into a patient’s dose it is, and even the experience level of the user.
For example, occasional users seem to experience a mild-to-moderate increase in blood pressure and heart rate shortly after consuming marijuana, peaking about 10-15 minutes later—followed by a modest hypotensive effect (a decrease in blood pressure). However, it seems tolerance plays a role too: among frequent cannabis users, there seems to be a more long-term effect on lowered heart rates and blood pressure—a net benefit in many’s view. .
However, experts say cannabis and synthetic cannabinoids in higher doses could trigger a heart rate increase that poses a serious risk to anyone with a pre-existing heart condition, and should therefore be avoided. And, sorry, joint junkies: so should smoking it.
Low-dose cannabis could save you from a heart attack or stroke
Excluding inhalation, a therapeutic dose of cannabis for the average user often delivers a decreased-blood pressure/increased-heart rate combo that’s cardioprotective, in that it helps protect the heart from damage. Limited evidence suggests that cannabis might also reduce atherosclerosis (a hardening of the arteries), as well as limit cell damage, and promote healing after a major cardiac event.
Cannabis’ drug-interactions with heart medications could pose a potential risk
Of particular concern to physicians and pharmacists are the potential interactions between cannabinoids and the suite of cardiovascular drugs prescribed today, including statins, antiarrhythmics, calcium-channel blockers, beta-blockers, and warfarin. So far the evidence isn’t great: bleeding disorders were observed in some patients (even more so with synthetic cannabis)—and could increase the potency of some statins. So if you’re on heart medication, talk to your doctor about medical marijuana before ruling out all the risks.
Heart disease is a condition that can stem from weight gain, and though advocates are working to overturn a decades-held assumption that pot automatically causes a weight-gaining munchie-effect (because it seems that for some strains, and over prolonged use, the opposite might be true), still: certain Indica-leaning strains of marijuana are one of nature’s finest appetite stimulants. It’s why physicians use it to treat chemo patients, and wasting diseases. So, if weight gain is a concern for you, consider switching to a more appetite suppressing, high-CBD strain of marijuana.
Edibles are safest for heart patients but beware of dosing
Smoking marijuana should be a ‘no-no’ for heart patients, but so should vaping. Experts are finding that even tobaccoless vaping causes problems with our blood vessels and blood flow in the body (not to mention opens up risk for a potential deadly lung injury). If people with heart problems use marijuana at all, experts say edibles are one of the safest choices—except for the possibility for dosing risk. It’s very easy to ingest a much higher dose of marijuana because the purity and dosing is so variable among different products, many patients don’t understand exactly how much is in each serving. And because high doses of cannabis can spike your heart rate, it puts you at risk for heart attack.
Several studies have found that (non-inhalant) medical marijuana, as well as isolated CBD, are showing to be safe and effective for older patients. Two recent studies showed that a high percentage (85% and 94%, respectively) of elderly patients reported improved symptoms after using medical marijuana just six months, with no ill side effects.This leaves cannabis an appealing option for physicians treating an ever-growing aging population whose hearts become more sensitive to drug interactions and other health concerns over time.
About the Author
Sarah A Lybrand is a writer specializing in lifestyle, health, finance, cannabis—and fun. She’s written for Yahoo Finance & Shine, Bust, Juno, MarketSmiths and Toast Media, among many others.