Does Marijuana Really Weaken Your Heart?
Let’s investigate the truth behind the most recent claims that marijuana use weakens heart muscle.
Ben Greenfield
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Does Marijuana Really Weaken Your Heart?
Recently, news hit the headlines that, according to a recent study, “marijuana use is associated with an almost doubled risk of developing stress cardiomyopathy,” which is a potentially fatal weakening of the heart muscle. Interestingly, prior to this most recent study, a 2016 study in rats found that one minute of exposure to marijuana smoke impairs the heart’s inner lining for 90 minutes, which is even longer than the impairment that occurs from smoking cigarettes.
This is a big deal, especially when you consider that marijuana is now in the process of being legalized in a significant number of states in the USA. Not only that, but an estimated 22 million Americans say they regularly use marijuana.
To confuse matters just slightly, at the same time as these new studies have been coming out, health experts have been changing their minds on the potential “deleterious effects” of marijuana. For example, CNN’s chief medical correspondent Sanjay Gupta reversed his opinion on medical marijuana and now believes that the drug should be fully legal for medical use. Harvard Health Review has reported that the health benefits of both medicinal and recreational use of marijuana include treatment of drug-resistant epilepsy a variety of psychiatric disorders (e.g., anxiety, substance use disorders, schizophrenia, and psychosis). A 1999 US Government sponsored study by the Institute of Medicine discovered more of these beneficial properties of marijuana in medical conditions such as nausea caused by chemotherapy, and wasting caused by AIDS, and since then, a number of studies have been done to show that smoked marijuana has pain reducing effects. Finally, a large number of small but significant studies have shown marijuana use to assist with medical conditions from alzheimers to glaucoma to arthritis, Crohn’s disease, and beyond.
So does marijuana really weaken your heart muscle? If it does, and if you’re also stressing your heart with exercise, this could be a huge worry. As a Get-Fit Guy listener and reader, anything that affects your risk of a medical issue during exercise should definitely be something you pay attention to, so today we’ll investigate the truth behind these most recent claims that marijuana use weakens heart muscle.
The first study, which appeared in a journal of the American Heart Association, looked into trends in hospital admissions and outcomes of adults with something called “transient ventricular regional ballooning (TVRB)” of the heart in response to marijuana use. TVRB is a form of cardiomyopathy, which is a sudden weakening of the heart muscle that can mimic symptoms of a heart attack. The symptoms include chest pain, dizziness, and shortness of breath, and the condition is often temporary but still significant.
Researchers in this study searched the 2003-2011 Nationwide Inpatient Sample database and identified 33,343 admissions for TRVB, of which 210 (0.06%) were related to marijuana use. Demographics, clinical characteristics, and outcomes of the two groups were then compared.
So what did the researchers report?
Marijuana users tended to be younger, more often male, and had lower (yes, lower!) prevalence of hypertension, diabetes, and hyperlipidemia, but also suffered more often from depression, psychosis, anxiety disorder, alcoholism, tobacco use, and substance abuse in general. They also more often suffered cardiac arrest and required placement of a pacemaker device. Meanwhile, congestive heart failure, which is a chronic condition that causes fluid buildup around the heart and affects chamber function in the heart, and fluid build up around your heart was more frequently observed in non-marijuana users.
In my opinion, this study simply shows this: frequent marijuana users may have a host of “issues,” like drug addiction, anxiety, and high blood pressure, and it’s likely that the “egg” (in this case, marijuana) actually occurred subsequent to the “chicken” (in this case the symptoms), and didn’t necessarily cause these symptoms. It’s well known that many folks who are having issues such as anxiety and depression often turn to substance abuse, including weed smoking. I don’t endorse this, but it is a common occurrence, and does not mean that the marijuana caused these issues. One could also argue that because the non-marijuana users experienced more congestive heart failure that these headlines could just as easily have read “Marijuana Protects Your Heart From Failing.” In light of the fact that these headlines occurred the day after the recent US elections and widespread legalization of marijuana, I suspect a bit of politics were at play. Finally, the marijuana users in the study were heavy, frequent users of the drug, which should also be taken into consideration.
The second study, also from the American Heart Association journal investigated whether brief exposure to marijuana smoke caused acute vascular endothelial dysfunction in rats. In vascular disease, endothelial dysfunction is simply a systemic pathological state of the endothelium (the inner lining of blood vessels) and can cause an imbalance between vasodilating and vasoconstricting substances produced by or acting on your blood vessels.
In this study, researchers measured endothelial function in the femoral artery of rats before and after exposure to marijuana smoke at levels similar to real‐world tobacco and cigarette smoking conditions. They reported that one minute of exposure to marijuana smoke impaired endothelial function to a comparable extent as impairment from equal concentrations of tobacco smoke, but recovery from the impaired function was considerably slower for marijuana. Exposure to marijuana smoke caused what is called “cannabinoid‐independent vasodilation” that subsided within 25 minutes, and the actual functional impairments of blood vessels remained for about 90 minutes, indicating that for about an hour and a half after smoking marijuana, your blood vessel function may be impaired.
I looked into this study in a bit more detail and discovered that the researchers used a modified cigarette smoking system in which a machine collects smoke from the burning tip of the cigarette or a marijuana joint in a Plexiglas chamber as a ventilator pump simulates human puffing. The wall of the chamber contains a gasket through which the nose of an anesthetized rat is inserted to breath the concentrated, smoky air for a full minute.
Not only is it highly unlikely that you’re going to be sticking your nose in a giant chamber of marijuana smoke (especially if you are using alternative forms of marijuana such as vaporizing or edible consumption), but even the authors of the study admit that it is highly possible that the increased heart attack risk was caused by the adverse effects of concentrated smoke on blood vessel function (specifically decreased nitric oxide production and high amounts of oxidative stress), and not anything special and unique in the marijuana itself.
When you combine these questionable aspects of both studies with the fact that cannibidiol (CBD) from both marijuana and hemp provides numerous health benefits that I’ve written about before, such as antioxidant, antiemetic, anticonvulsant, and anti-tumoral properties, along with counteracting the psychoactivity of THC, and acting as a natural antidepressant and neuroprotective agent, it should give you pause and make you reconsider whether marijuana really causes heart attacks.
Ultimately, it looks like heavy marijuana use in people with preexisting conditions may cause some heart issues and protect against others, and the breathing of extremely concentrated smoke from anything, including marijuana and tobacco, may impair blood vessel function. But despite the juicy headlines, that’s about all we can take away from these studies.
Do you have questions, comments or feedback about whether marijuana weakens your heart? Join the conversation at Facebook.com/getfitguy. Finally, I am not a doctor and this is not to be taken, interpreted, or construed as medical advice. Please talk with a licensed medical professional about this. These are just my own personal thoughts and not a prescription or a diagnosis or any form of health care whatsoever. Any use of any recreational or medicinal drug should always be practiced by only those of legal age under full legal conditions and with moderation and responsibility.z
About the Author
Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.