An increasing number of states are legalizing marijuana for recreational and medical use, but emerging evidence suggests it may have significant effects on cardiovascular health. 

Nebraska Medicine cardiologist Christina Dunbar Matos, DO, explains what the latest research shows, who may be at greatest risk, and when to seek medical attention.

How strong is the evidence linking marijuana use to cardiovascular events?

According to Dr. Dunbar, multiple studies have linked marijuana use to an increased risk of heart attack and stroke.

A recent meta-analysis published in the journal Heart found marijuana use was associated with a 29% higher risk of heart attack, a 20% higher risk of stroke, and nearly double the risk of death from cardiovascular disease.

"The American College of Cardiology recognizes that marijuana use can significantly increase the risk of heart attack and stroke," Dr. Dunbar says. "One study found this increased risk persisted even in people who had no other traditional risk factors for heart disease."

Although more research is still needed, findings have become increasingly consistent across studies, raising concerns among cardiovascular experts.

"There is real concern within the medical community that the long-term effects of marijuana use will lead to worsening cardiovascular health later in life, especially as marijuana becomes more common," Dr. Dunbar says.

How does marijuana affect the heart and blood vessels?

"Marijuana causes inflammation of the blood vessels, similar to tobacco," Dr. Dunbar says. "This can increase plaque formation and blood clot development, raising the risk of heart attack and stroke."

Potential short-term health effects include:

• Changes in heart rate. 
• Changes in blood pressure. 

Potential long-term health effects include:

• Inflammation and damage to blood vessels. 
• Increased plaque buildup. 
• Increased risk of blood clots. 
• Greater risk of heart attack and stroke. 
• Heart damage that may eventually contribute to heart failure. 

Who is most at risk?

People with existing cardiovascular disease or traditional risk factors for heart disease and stroke are at the greatest risk. However, Dr. Dunbar says researchers are also concerned about the potential long-term effects of marijuana use in younger adults.

"There is a real concern about the effect chronic marijuana use may have on younger adults, particularly later in life," she says.

Research also suggests marijuana may increase the risk of heart attack and stroke even in otherwise healthy individuals.

Does the method of marijuana use matter?

Yes. Smoking marijuana appears to pose the greatest cardiovascular risk, but vaping and edible forms are not without risk.

"Some of the harmful effects, including blood vessel damage, have also been seen with edibles, although more research is needed to fully understand the overall impact," Dr. Dunbar says.

What warning signs should you watch for?

Anyone experiencing possible symptoms of a heart attack or stroke should seek immediate medical attention.

Potential warning signs include:

• Chest pain. 
• Shortness of breath. 
• Sudden numbness or weakness, especially on one side of the body. 
• Difficulty speaking or understanding speech. 
• Worsening fatigue.

What should patients know before using marijuana?

"Just because marijuana is considered a 'natural' substance doesn't mean it's safe to use," Dr. Dunbar says. “While there are medicinal properties, it is recommended that it be used under the guidance of a doctor or qualified health care provider.”

Whether or not you use marijuana, Dr. Dunbar says the best way to protect your heart is to focus on prevention and work with your doctor to manage your overall cardiovascular risk.