Ingesting marijuana may have higher heart risks than smoking it, but both methods carry dangers, per a recent study

By Claire Wolters | Fact-checked by Davi Sherman
Published November 10, 2023

Key Takeaways

  • New research links marijuana use to harmful cardiovascular complications.

  • More studies are needed to understand why these connections exist and if the method of use plays a role in risk level.

  • Studies on marijuana’s safety and efficacy have been limited and delayed due to cannabis’s label as a Schedule 1 drug.

People who use marijuana could be at increased risk for heart complications like heart attack and heart failure, according to new research presented by the American Heart Association (AHA) at its 2023 Scientific Sessions conference.[][]

In the research that was presented, studies linked regular marijuana use to stroke, heart attack, and heart failure, even when accounting for other coexisting cardiovascular risk factors like Type 2 diabetes, high blood pressure, and obesity.

One study found that daily marijuana use is associated with incident heart failure, showing a 34% increased risk of developing heart failure for daily users compared to those who reported never using the substance. In this study, marijuana use is defined as “using marijuana when not prescribed for a health condition, or, if prescribed for medical purposes, using it beyond that purpose.”[]

Another study showed that for adults older than 65 with cardiovascular risk factors who did not use tobacco, cannabis (the medical term for marijuana) use can increase the risk of major adverse heart and brain events.[]

In the findings presented, researchers did not separate results based on method of use.

What makes marijuana risky?

More studies are needed to flesh out the reasons behind marijuana’s impact on the heart. Some researchers suggest that the method of use may affect risk levels, with smoking potentially being riskier than other methods.

In a 2020 statement, the AHA said that cannabis’s impact on cardiovascular health “may be mediated by mechanisms of delivery.” 

“Cannabis may have therapeutic benefits, but few are cardiovascular in nature,” the AHA wrote. “Conversely, many of the concerning health implications of cannabis include cardiovascular diseases…”

However, the studies did not separate for inhaled versus consumed marijuana.

Richard Wright, MD, a board-certified cardiologist at Providence Saint John’s Health Center in Santa Monica, CA, says that “the most important and glaring problem is that the studies did not discern whether daily marijuana use meant use of inhaled marijuana, or frequent ingestion of edible cannabis.”

“This is a critical issue, as any inhaled combustible material contains noxious substances, which are known to have potential pulmonary, cardiovascular, and systemic adverse effects,” Dr. Wright said.

On the other hand, consuming marijuana may subject people to a different set of health risks.

“It is thought that ingesting THC increases systolic absorption of the chemical when compared to smoking THC, and thus results in greater adverse effects,” says Cheng-Han Chen, MD, a board-certified interventional cardiologist and Medical Director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA.

Tolerance and risk level 

It is also people’s tolerance for marijuana/cannabis that may impact their risk levels for cardiovascular complications, Dr. Wright says.

“In almost all circumstances, there is a dose-response relationship to intake of deleterious substances, and this could mean that occasional use of marijuana might not be as risky for enhancing the chance of future cardiac events—or at the least, might be less risky,” Dr. Wright explains.

People who use marijuana more frequently might also be using it to soothe co-occurring conditions, which could be responsible for increasing their risk for cardiovascular events, he adds.

“These confounders make it impossible to state with conviction that marijuana leads to higher likelihood of cardiac events, even if the drug indeed has such an effect,” Dr. Wright says.

Marijuana’s research roadblocks

Researchers’ “understanding of the safety and efficacy of cannabis has been limited by decades of worldwide illegality and continues to be limited in the United States by the ongoing classification of cannabis as a Schedule 1 controlled substance,” the AHA wrote in its 2020 statement.[][]

This impact is profound, affecting how doctors can treat and advise patients.

“We are only now beginning to better understand the effect of cannabis use on heart health,” Dr. Chen says. “We have known that THC has effects on the cardiovascular system, such as increasing sympathetic tone, endothelial dysfunction, and oxidative stress, but it is only in the last few years that researchers have gathered data associating cannabis use [with] worsened clinical cardiovascular outcomes.”

At the end of the day, “any form of cannabis use does involve some risk to your health,” Dr. Chen adds. “Everyone has to decide for themselves how much risk they want to expose themselves to.”

Dr. Wright encourages doctors to take the research seriously but not to use marijuana or cannabis as a sole determinant of a person's heart health risks. 

Encourage at-risk patients to prioritize general health management and to “make sure that elevated cholesterol, diabetes, and high blood pressure are controlled; that exercise is regularly undertaken; that cigarettes are completely avoided; and that obesity and poor diet are avoided, ” he says.

What this means for you

Marijuana use may increase risks for serious heart complications, including heart attack and heart failure, according to new research. If and to what extent risks differ for those who inhale versus ingest the substance is unclear.

Share with emailShare to FacebookShare to LinkedInShare to Twitter