Is Marijuana Messing With Your Heart?

As marijuana continues to become more widely used, it’s also increasing in potency and accessibility, available in a host of different forms like edibles and vape pens. And as its usage grows, so does the research on its potential effects on the heart.

Now legal for recreational use in 24 states and for medicinal use in 38 states, the latest numbers show that about 1 in 5 people over the age of 12 – nearly 62 million people -- have used marijuana in the past year, up from 52.5 million the year prior.

One study found that smoking marijuana at least once a month is linked to an elevated risk of heart attack. A November 2023 report from the American Heart Association (AHA) highlighted two studies that found marijuana use was linked not only to a greater risk of heart attack but also heart failure. Another found that those using medical marijuana for chronic pain had a 64% increase in their risk of abnormal heart rhythms, or atrial fibrillation, which makes you more at risk for a stroke.

It’s well-known that inhaling smoke of any kind is bad for the lungs. But when it comes to marijuana, its active ingredient, known as THC (tetrahydrocannabinol), could be affecting the body in a different way. THC activates the sympathetic nervous system, a network of nerves responsible for the body’s “fight-or-flight” response. This response can trigger an increased heart rate and blood pressure, both of which put more strain on the heart. Research also suggests that using THC frequently could lead to inflammation in blood vessels, which could then affect the buildup of plaque in the arteries.

The levels of THC in marijuana also continue to increase, and the dosage may be the key factor influencing the increased risk. Many of the studies available today were several years in the making, as it takes time to conduct research and evaluate results. That means they were likely done using older, less potent forms of marijuana than what’s commonly available today and looked only at people who smoked it. More research is needed on how the THC in vape pens and edibles, from gummies to cookies to teas, may affect heart health.

It’s important to note that just because marijuana is legal in some states for medical or recreational adult use, doesn’t mean it’s safe. Using it daily or nearly every day can lead to negative health consequences like memory, attention and learning issues. Its use has also been linked to social anxiety and depression, among other mental health issues, and it can also make those symptoms worse. In addition, using marijuana during pregnancy or while breastfeeding may harm the baby. If you or a loved one is struggling with substance use, the SAMHSA’s national helpline is a free, confidential, 24/7 resource: 1-800-662-HELP (4357).