With marijuana (cannabis) becoming legalized more and more in the United States, its recreational and medical use has risen rapidly, including among people with heart disease. Some members of MyHeartDiseaseTeam have shared that they use medical marijuana to help them feel better: “I also have peripheral artery disease. Today, though, with the help of medical marijuana, I’m feeling fine!” one member wrote.

One common way to use marijuana is to smoke the dried cannabis plant. Research has definitively shown that smoking cigarettes is a risk factor for heart disease. But what does research show about the effect of smoking marijuana on the heart?

Here is what you need to know about smoking marijuana with heart disease, including how it may affect heart health and whether it can help relieve heart disease symptoms. As with any new treatment, talk to your cardiologist or another health care provider before trying marijuana for heart disease. They can help you weigh its potential risks and benefits, assess its safety given your heart health and overall health, and help you make the best decision on whether or not to use marijuana.

What Is Marijuana?

Marijuana is derived from dried leaves and flowering tops of the cannabis plant. There are several different ways to consume marijuana — some people smoke the dried plant and some vaporize cannabis oil at high heat. Other people apply topical products that contain cannabis extract or consume products made with the extract (called edibles), including gummies, chocolate, cookies, and more.

Humans have cultivated and consumed marijuana for more than 6,000 years. Studies have found that some preparations of marijuana may help with certain kinds of pain, nausea and vomiting (especially associated with chemotherapy), seizures, glaucoma, and more. However, these conclusions are currently tentative, and research is ongoing.

Scientific research regarding the benefits or risks of marijuana use is limited in part because governments that banned it have also banned scientists from doing the appropriate studies. Such is the case in the U.S., where marijuana is still illegal by federal law. In addition, unlike prescribed medications, marijuana preparations are not regulated so that contents or dosages can be adequately measured.

At this point, more scientific research must be done to fully understand marijuana and determine how and when to use medical marijuana for benefit.

Marijuana, Heart Disease, and Heart Health

Some people assume that smoking marijuana is not as dangerous as smoking cigarettes. However, the dangers of smoking marijuana are not entirely known, given the limited research.

Researchers have found that, shortly after smoking marijuana, people may experience an increased heart rate and elevated blood pressure. These effects may increase the risk of complications in people living with heart disease. A study from 2001 reported people had a five times higher risk of having a heart attack within the first hour of smoking marijuana.

Most studies that tie marijuana smoking to heart problems — including the one mentioned above — are based on reports from the users themselves. As such, it’s not always possible for researchers to know whether these study participants may be engaging in other behaviors that could contribute to heart problems, such as using other substances like cocaine. This is a major problem in judging the reliability of such studies.

Ultimately, however, there is some reliable research connecting cannabis use to certain symptoms or conditions that can be dangerous to people with heart disease. Here’s what researchers have found so far.

Marijuana and Inflammation

It’s unknown exactly how inflammation is connected to the causes of heart disease. However, it appears to be connected to atherosclerosis (thickening of arterial walls) due to a buildup of plaque (deposits of fats, cholesterol, and even dead blood cells) in the blood vessels.

Marijuana may contribute to inflammation in the blood vessels, which can lead to atherosclerosis. In one study, researchers looked at nearly 35,000 people ages 40 to 69 who smoked marijuana. They found that people who smoked a marijuana cigarette had higher levels of molecules indicating inflammation in their blood within the first three hours.

These findings are backed up by laboratory research. Human endothelial cells (the cells that line the blood vessels) become more inflamed and show signs of atherosclerosis after exposure to THC, the main psychoactive component of marijuana that causes the high associated with the drug.

These effects may be worse in people who are already more likely to have heart disease. When lab mice were bred with higher-than-normal levels of cholesterol and fed a high-fat diet, they were even more likely to develop atherosclerosis when exposed to THC than mice without those factors.

Some researchers believe that frequent marijuana use may make these results worse. THC binds to a receptor called CB1, which recognizes natural cannabinoids. In the short term, this is why marijuana may help with pain, mood, and more. Long-term use, however, results in overactivation of the CB1 receptor. This, in turn, can cause inflammation and atherosclerosis.

In the future, researchers may find other molecules that block this inappropriate activation of the CB1 receptor. However, for now, certain cannabis use — especially long-term use — seems to contribute to inflammation and atherosclerosis, which also contribute to cardiovascular disease.

Marijuana and Atrial Fibrillation

Marijuana may not pose additional risks to heart health in people living with atrial fibrillation (AFib) and other types of arrhythmia (irregular heartbeat).

More research is needed to identify how and when marijuana may actually benefit (or harm) those with AFib. One study showed that, in people who had experienced one heart attack, smoking marijuana did not raise their chances of experiencing ventricular fibrillation or ventricular tachycardia, which are types of arrhythmias.

In addition, people who smoked marijuana regularly had a lower chance of experiencing AFib after their heart attack, suggesting possible positive effects of marijuana on heart rhythm. It’s important to recognize that this does not mean that marijuana should be used to treat AFib.

At least one MyHeartDiseaseTeam member with AFib has reported feeling better when consuming cannabis: “I have AFib, marijuana helps,” they wrote.

Other studies seem to contradict the above findings. No one who lives with AFib should try to treat their condition with marijuana without consulting their cardiologist first. Together, you determine whether marijuana use may be safe and helpful for you. If your cardiology expert advises against it, they can help you come up with alternate ways of feeling better or managing your AFib symptoms. Most people living with AFib may also require a type of drug called anticoagulants. It’s unclear how marijuana may interact with this treatment.

Potential Irritants in Cannabis Smoke

Smoking marijuana involves inhaling more than just the active chemicals of the cannabis plant. You’re also inhaling various irritants and other chemicals.

Thus far, research has not always isolated the effects of marijuana from the effects of these other substances. Some of the effects attributed to marijuana might be caused by these other molecules, instead. More research is needed to determine the effects of cannabis and its active ingredients on heart health and the body overall.

Talk to Your Cardiologist

Health care experts generally recommend that people with heart disease avoid smoking or vaping marijuana. There are too many risks and too many unknowns, at least at this point, for its use to be deemed safe for those with heart conditions.

If you still want to smoke marijuana, either recreationally or medicinally, and you have been diagnosed with heart disease, talk to your health care provider first. They may recommend that you avoid smoking marijuana, or they may work with you to come up with a plan for use that takes your heart disease into account. They may also help you use some of the non-psychoactive parts of the cannabis plant, like cannabidiol (CBD), which may have different effects.

Either way, if you are living with heart disease, you should be open and honest with your doctors about your marijuana consumption. That way, they can help monitor for negative effects and take steps to make them less severe if your condition seems to be worsening.

Find Your Team

On MyHeartDiseaseTeam, more than 52,000 people living with heart disease come together to ask questions, give advice, and share their stories with others who understand life with heart disease.

Are you or a loved one living with heart disease? Consider joining MyHeartDiseaseTeam today. This is the online social network for people who live with heart disease and those who love and care for them. Here, you can share your journey, ask and answer questions, and join ongoing conversations. Before long, you’ll have a team of members from around the world who understand life with heart disease.

Do you use marijuana to alleviate the symptoms of heart disease or another diagnosis? Do you have questions about medical or recreational marijuana? Share your thoughts in the comments below or by posting on MyHeartDiseaseTeam.