Cannabis Made Clear

Cannabis and Heart Health

Time for a pulse check: Examine the latest research into how consuming cannabis, and particularly smoking it, may impact your heart and cardiac health.  

Hand of doctor placing stethoscope on patient's chest

If you’re a regular cannabis consumer, you may already know how smoking cannabis can affect your lungs. But what about the effects of cannabis on other organs? A look at the current research reveals that consuming cannabis by smoking could cause some heartache too.

Most Canadians who consume cannabis smoke it, but historically, most smoking research has focused on tobacco. Now that cannabis is legal for adult use across Canada, researchers are exploring new opportunities for study that can help us understand the effects of cannabis smoke on the body, including cardiac (or heart-related) health.

Studies are looking at how different methods of consumption and cannabis products — vaping and edibles, for example — affect the heart. More research is needed to understand nuances such as whether THC potency matters to cardiac health and how smoking cannabis compares to smoking tobacco. Read on to get a better understanding of how much risk cannabis smoke presents to your heart health.

What are the potential long-term cardiac impacts of smoking cannabis?

Despite the limitations of current studies, enough preliminary evidence exists for both the Heart and Stroke Foundation of Canada and the American Heart Association to caution against smoking or vaping cannabis because of the potential cardiac consequences.

“Many consumers and healthcare professionals don’t realize that cannabis smoke contains components similar to tobacco smoke,” said researcher and professor Robert L. Page II in a 2020 statement for the American Heart Association. Over 4,000 of the same chemicals are present in both cannabis and tobacco smoke, including ammonia, benzene, carbon monoxide, hydrogen cyanide and tar. Plus, cannabis smokers tend to inhale more smoke and hold it in their lungs longer compared to tobacco smokers.

These factors may help explain why smoking cannabis has been shown to be associated with higher levels of cardiac events ​—​ including chest pain, stroke, heart attack, heart failure, atrial fibrillation, arrhythmias and cardiac arrest — when compared with not smoking cannabis.

Long-Term Effects of Cannabis Consumption

Consuming cannabis and cannabinoids (such as THC) daily or almost daily over a long time increases the risk of developing long-term effects, including:

  • problematic use patterns or cannabis use disorder
  • long-lasting concentration and memory impairment
  • mental health disorders
  • lung infections and/or bronchitis  
  • damaged blood vessels
  • impacts on the brain

What causes the cardiac health effects of consuming cannabis?

We know that inhaling the smoke is linked with cardiac conditions, but that’s not the whole story of cannabis’s potential effects on the heart.

Consuming the cannabinoid tetrahydrocannabinol, or THC, can raise heart rate (called tachycardia), increase blood pressure, dilate blood vessels and cause the heart to pump faster. The THC in cannabis also stimulates the nervous system and is implicated in the body’s “fight or flight” response. It may also cause fear, paranoia and anxiety in some users.

All of these effects can stress the heart, but more research is needed to separate out the specific cardiac impacts of smoke, THC and other cannabinoids and to understand how the dose or method of consumption come into play.

Does frequency of cannabis consumption affect the risk?

Yes, it seems that it does matter how often you smoke. In a 2022 study from Stanford Medicine, researchers found that people who smoke cannabis more than once a month have a higher risk of heart disease and heart attack.

More recently, the American College of Cardiology cautioned that daily cannabis smokers are 34% more likely to be diagnosed with coronary artery disease (CAD) compared to non-cannabis smokers, regardless of possible factors such as tobacco or alcohol use. At the same time, those who smoked only monthly didn’t demonstrate significantly increased CAD rates at all. We also know that cannabis use disorder, a pattern of frequent and problematic cannabis use, is linked to an increased risk of heart attacks in people under 50 and to a significantly higher risk of cardiovascular disease.

“Our study doesn’t provide enough information to say that cannabis use disorder causes adverse cardiovascular disease events,” said Dr. Anees Bahji, lead author of the Canadian study that found higher rates of cardiovascular disease in people with cannabis use disorder, “but we can go so far as to say that Canadians with cannabis use disorder appear to have a much higher risk of cardiovascular disease than people without the disorder.”


How do I decide if a cannabis tolerance break, or T-break, is right for me?


Are the cardiac effects of cannabis the same for everyone?

Cannabis affects everyone differently. In the short term, this could mean a euphoric experience for some and a paranoid one for others. In the long term, the potential risks and benefits of cannabis intersect with several factors, including lifestyle, age, weight, sex, socioeconomic status and underlying health conditions.

The bottom line? People with heart concerns should be cautious about using cannabis.

“For people diagnosed with heart disease, cannabis should be used with extreme caution because cannabis increases the heart’s need for oxygen at the same time as it decreases available oxygen supply, which could cause angina (chest pain),” reads a 2020 scientific statement from the American Heart Association. Health Canada agrees, citing tachycardia, or a rapid heart rate, as a particular side effect of concern: “While cannabis-induced tachycardia is not usually considered dangerous for healthy young users, it may be dangerous to those already suffering from cardiac disorders or angina.”

If you have a heart condition, it’s a good idea to consult your doctor before consuming cannabis. And heart condition or not, if you choose to consume, consider harm-reduction practices that can minimize the risks of cannabis.

 

Next
The Effects of
Cannabis on the
Lungs
The Effects of Cannabis on
the Lungs