Medicinal marijuana can be prescribed for some severe conditions like cancer and seizures. But can it ease or improve heart failure? Conversely, can cannabis make heart conditions worse?
These are all excellent questions that are being continually asked as we start to learn more about how cannabis affects heart failure.
Even though the evidence is currently limited, many experts believe it is dangerous for those with heart failure to consume cannabis.
Therefore, with the popularity of cannabis having increased in the UK, US, and Western Europe over recent years, learning exactly how cannabis affects the body is vital. [1]
What’s more, those who begin their cannabis consumption and addiction habit in younger life are at greater risk of developing heart disease later in life, a recent University of Guelph study finds. [2]
Due to its prohibited status, it’s limited to no-medical use and has a high potential for abuse; unfortunately, studies about cannabis’s consequences on the body are limited.
But what is known is that cannabis use could damage the heart and blood vessels. The research available to us now can be damning, determining that cannabis has zero cardiovascular benefits but severe potential consequences.
However, the study admits that more research is needed to determine the actual effects of cannabis on the heart. In addition, we need to know its cardiovascular safety as its popularity continues to spread. [3]
According to a report by the American Heart Association, observational studies link the natural or synthetic chemicals in marijuana such as THC (tetrahydrocannabinol) to a greater risk of heart failure, heart attacks and heart rhythm disorder known as atrial fibrillation.[4]
The British Heart Foundation (BHF) makes similar claims about cannabis, claiming it has been linked to a damaged heart.
However, a study by the Queen Mary University of London found that frequent cannabis consumption was associated with an increase in the heart’s left ventricle or the main pumping chamber.
They found that this thickening of the muscle wall caused reduced blood flow out of the heart and around the rest of the body. This thickening increases the risk of circulator diseases such as stroke and heart attack.
In addition, early signs of reduced heart function were found in recreational cannabis users.[5]
Research into the age of cannabis users also sheds light on the potential dangers of cannabis use on the heart.
According to a study conducted by the Canadian Medical Association Journal on people aged 18 to 45, it was found that cannabis can increase your risk of a heart attack, whether you eat, vape, or smoke it. [6]
As already mentioned, the University of Guelph research also indicates that smoking cannabis when you’re young could raises your risk of developing heart disease later in life.
This first study of its kind, it looked at healthy young cannabis users and their specific risk indicators for cardiovascular disease (CVD).
Unfortunately, subtle but potentially significant changes to the heart and artery function were found by researchers. Ultrasound imaging was used to measure the ability of the arteries to properly expand with more substantial blood flow, arterial stiffness, and arterial function.
All three tests are critical indicators of cardiovascular function and potential heart disease risk. Some of the results include greater arterial stiffness in cannabis users than non-users. Additionally, essential cardiac function was also lower than in non-cannabis users.
However, the team were surprised to find no difference in artery dilation between both groups in response to a change in blood flow. Again, these intriguing results demonstrate how further research is needed.
Research has found that cannabis can have a detrimental impact on the cardiovascular system in several ways, including;
It’s suggested that cannabis has similar consequences to cigarettes in that it narrows the blood vessels around the heart. This narrowing makes it harder for the heart to pump the essential lifeblood around the body.
Some animal studies suggest that cannabis can lessen the heart’s capacity for pumping and contracting.
When people already suffer from an unsteady or out-of-rhythm heartbeat, they risk making it more unstable with marijuana use.
Consuming marijuana when you already have high blood pressure is a bad idea, as ultimately, it can make it worse. Doctors can then find managing the patient’s blood pressure more challenging.
There’s the suggestion that people wouldn’t consume medicinal marijuana if it had zero beneficial effects, such as self-medication for anxiety and depression.
Although more evidence is needed, some evidence suggests that medical marijuana can benefit chronic pain after being legalised for therapeutic use in the UK in 2018 and 36 US states since 1996.
Marijuana is usually smoked, vaped, or eaten. Whichever way you consume it, the primary cannabinoid component of THC (tetrahydrocannabinol) will cause that typical ‘high.’ [7]
Marijuana can be a therapeutic option for pain management due to how its cannabinoid compounds interact with the receptors in the brain, slowing down those impulses and easing discomfort.
What’s more, cannabinoids have been shown to affect nausea and vomiting, along with inducing appetite positively.
These combining factors make marijuana an extremely suitable option for those going through chemotherapy and the consequent weight loss.
Although, for conditions such as diabetes and thyroid problems, appetite stimulation with cannabis use would be counterproductive.
Although cannabis can assist with pain and chemotherapy treatments, it can have detrimental effects on medications individuals may take for other conditions.
Your liver makes enzymes to help process any medications taken for heart failure. Marijuana can be dangerous in that it can affect these enzymes in how the liver breaks cannabis down.
Medication taken for heart failure may leave your body earlier or later than it should because of these affected enzymes.
The types of heart failure medications that could be affected include;
Although it’s clear that cannabis has some benefits for pain management, there’s no proof that cannabis products offer any help at all to heart health, as reported in the American Heart Association’s scientific statement. [8]
Although more research is needed into the full risks of cannabis on heart health, researchers currently know that marijuana users may be at increased risk of a rhythm disorder called atrial fibrillation, heart failure, or heart attack.
As a class B drug in the UK and a class 1 controlled substance in the US, it’s difficult for scientists to conclude in-depth studies. But, although more research is needed, the consensus is that cannabis is likely to have more negatives than positives.
So far, it’s clear that the risks of cannabis on the heart are more significant than any benefits it might have. But the question remains; what causes cannabis to affect the heart, the THC or smoke?
Other studies by American Heart Association’s Scientific Sessions also indicate that patients who consumed marijuana and had undergone an artery-clearing procedure after a heart attack had a higher rate of following heart attacks than those who didn’t.
However, these studies intriguingly found that certain heart attack risk factors such as high cholesterol, diabetes, and hypertension were lower in cannabis users.
This study reiterates the common theme that more research is needed.
For example, none of the studies indicates whether the increased risks of marijuana on the heart comes from the marijuana itself, the THC, or the smoke released from burning a plant-based product or tobacco products.
Studies can be conflicting when reporting increases in blood pressure, bleeding, stroke, and second heart attacks in cannabis users, but improvements in certain cardiovascular risk factors (discussed above).
What’s even more confusing is the lower rate of kidney failure found among cannabis users in these American Heart Association’s Scientific Sessions studies, suggesting again that cannabis may have other benefits for the body.
These studies and the questions they leave unanswered make it clear how much is still unknown in terms of the negative or positive health effects of cannabis.
Although clinical research into humans is still limited, the consensus is that cannabis use has more downsides to the body’s health than positives.
[1] Alcohol, Drugs, and Addictive Behaviours Unit.
[2] Early Cannabis Use Linked to Heart Disease, says U of G Researchers
https://news.uoguelph.ca/2021/04/early-cannabis-use-linked-to-heart-disease-say-u-of-g-researchers/
[3] Role of cannabis in cardiovascular disorders
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5542986/
[4] Marijuana may hurt heart, more research needed, report finds
https://www.heart.org/en/news/2020/08/05/heart-risks-of-marijuana-use-need-more-research
[5] Cannabis linked to damage heart
[6] Recent cannabis use and myocardial infarction in young adults: a cross-sectional study
https://www.cmaj.ca/content/193/35/E1377
[7] Marijuana Research Report, What is marijuana?
https://nida.nih.gov/publications/research-reports/marijuana/what-marijuana
[8] Medical Marijuana, Recreational Cannabis, and Cardiovascular Health: A Scientific Statement From the American Heart Association
https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000000883
Boris is our editor-in-chief at Rehab 4 Addiction. Boris is an addiction expert with more than 20 years in the field. His expertise covers a broad of topics relating to addiction, rehab and recovery. Boris is an addiction therapist and assists in the alcohol detox and rehab process. Boris has been featured on a variety of websites, including the BBC, Verywell Mind and Healthline. You can connect with Boris online at LinkedIn or X.com.
