The new scientific statement, published Wednesday in the AHA journal Circulation, examined existing research on the connection between cannabis and the heart
“The American Heart Association recommends that people not smoke or vape any substance, including cannabis products, because of the potential harm to the heart, lungs and blood vessels,” said Dr. Rose Marie Robertson, the deputy chief science and medical officer for the American Heart Association, in a statement.
The statement found using weed has “the potential to interfere with prescribed medications” as well as “trigger cardiovascular conditions or events, such as heart attacks and strokes,” said clinical pharmacologist Robert Page II, who chaired the medical writing group for the statement.
Page, who is a professor in the Department of Clinical Pharmacy and Physical Medicine / Rehabilitation at the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences in Aurora, Colorado, said anyone wanting to use marijuana should first address potential risks with their health care provider.
“If people choose to use cannabis for its medicinal or recreational effects, the oral and topical forms, for which doses can be measured, may reduce some of the potential harms,” Page said in a statement.
“It is also vitally important that people only use legal cannabis products because there are no controls on the quality or the contents of cannabis products sold on the street,” he added.
Some of the studies analyzed by the medical group found heart rhythm abnormalities, such as tachycardia and atrial fibrillation, could occur within the hour after weed containing THC is smoked. THC, or tetrahydrocannabinol, is the psychoactive substance within marijuana that creates a “high.”
According to other studies, tetrahydrocannabinol can also cause a faster heart rate, increase the need for oxygen in the heart, disrupt the walls of the arteries, and contribute to higher blood pressure while being prone.
“Cannabis smoke contains components similar to tobacco smoke,” Page said, and studies show tobacco-like increases in carbon monoxide and tar in a weed smoker’s blood after smoking marijuana, regardless of the THC content.
Chest pain, heart attacks, heart rhythm disturbances, and other serious heart conditions are associated with both tobacco and marijuana carbon monoxide intoxication, the statement said.
Risks are on the increase for anyone with existing heart disease. Research indicates that smoking marijuana has caused heart attacks, increased risk of strokes, and heart failure in individuals with chronic heart disease.
In comparison, one of the other 80 chemicals in cannabis, CBD, or cannabidiol, does not provide the “high” typically associated with THC. It doesn’t seem to affect the head, either.
Despite the hundreds of products currently being sold over the counter and online, the group wrote that there is only one CBD-derived product approved by the US Food and Drug Administration. All these scientific results have one caveat: There are current studies on marijuana and the heart
“short-term, observational and retrospective studies, which identify trends but do not prove cause and effect,” Page said.
There is an “urgent” need for “carefully designed, prospective short- and long-term studies regarding cannabis use and cardiovascular safety,” Page added.
Yet this is hard to do in today’s world, as the U.S. Drug Enforcement Administration classifies marijuana as a Schedule I controlled substance. That dramatically limits research and the DEA should remove those restrictions to allow scientists to study the effects of marijuana better, the group advised.
Moreover, the medical group proposed that cannabis be part of the tobacco control and prevention efforts of the US Food and Drug Administration, which may mean that there will be age limits on who can buy marijuana, dealer controls, and even excise taxes.
According to Michelle Kirkwood, an AHA spokesperson, the American Heart Association is looking into the research statement and will be issuing new policy changes in the coming weeks.
“The public needs fact-based, valid scientific information about cannabis’s effect on the heart and blood vessels,” Page said.
“Research funding at federal and state levels must be increased to match the expansion of cannabis use — to clarify the potential therapeutic properties and to help us better understand the cardiovascular and public health implications of frequent cannabis use.”