A new study claims marijuana is tied to a threefold risk of dying from high blood pressure — but there’s a catch
A new study suggests that anyone who smokes marijuana faces a threefold risk of dying from high blood pressure than people who have never used the drug.
Those findings sound alarming, but it’s important to keep in mind that, like any study, this one has limitations, including that it defines marijuana “users” as anyone who’s ever tried the drug and that it doesn’t differentiate among strains of a highly unregulated product.
However, the study highlights some key areas for future study — including how using cannabis might affect the heart. Here’s what you need to know.
‘A greater than three-fold risk of death’
“We found that marijuana users had a greater than three-fold risk of death from hypertension and the risk increased with each additional year of use,” Barbara Yankey, the lead author of the study and a doctoral student of epidemiology and biostatistics at Georgia State University, said in a statement.
For her paper, published Wednesday in the European Journal of Preventive Cardiology, Yankey looked at more than 1,200 people age 20 or older who had been recruited previously as part of a large and ongoing national health survey.
In 2005, researchers asked them whether they had ever used marijuana or hashish. People who answered “yes” were classified as marijuana users; those who answered “no” were classified as nonusers.
Overall, those classified as marijuana users were found to be 3.42 times as likely to die from hypertension, or high blood pressure, than those who said they had never used. That risk also appeared to rise by a factor of 1.04 with what the researchers labeled “each year of use.”
Here’s the problem: The study’s authors defined anyone who said they had ever tried marijuana as a “regular user.”
Other research suggests this is a poor assumption. According to a recent survey, about 52% of Americans have tried cannabis at some point, yet only 14% said they used the drug “regularly,” defined as “at least once a month.”
Also, the study was observational, meaning it followed a group of people over time and reported what happened to them, so the researchers cannot conclude a cause and effect — they can’t say that smoking marijuana causes high blood pressure, only that the two things appear to be linked. The authors wrote, “From our results, marijuana use may increase the risk for hypertension mortality.”
Another issue is the unregulated nature of the existing, and largely illegal, cannabis market. People are using a wide variety of strains whose concentrations of compounds — there are up to 400 in marijuana, including THC and CBD — can differ drastically.
Charles Pollack, who directs the Lambert Center for the Study of Medicinal Cannabis and was not involved with the new study, told LiveScience that there were many strains of marijuana “with no quality standards,” and that was “making it tough to generalize” the effects.
Marijuana and your heart
While the study is far from conclusive, it sheds light on an important potential health risk linked with marijuana use. Scientists know that cannabis affects the heart, but because of the limited research available on the drug, it has been hard to suss out how it affects things like high blood pressure.
For example, according to the National Institute on Drug Abuse, ingesting marijuana increases heart rate by between 20 and 50 beats a minute for anywhere from 20 minutes to three hours.
But a large, recent report from the National Academies of Sciences, Engineering, and Medicine found “insufficient evidence” to support or refute the idea that cannabis might increase the overall risk of a heart attack, though it also found some limited evidence that using the drug could be a trigger for the phenomenon.
When it comes to cannabis’ effect on blood pressure, the results are also inconclusive. One very small study, for example, found a sharp increase in blood pressure immediately after regular pot users stopped using the drug.
“Abrupt cessation of heavy cannabis use may cause clinically significant increases in blood pressure in a subset of users,” that study’s researchers wrote.
And according to the Mayo Clinic, using cannabis could result in decreased, not increased blood pressure.
Francesca Filbey, the director of cognitive neuroscience research of addictive disorders at the Center for BrainHealth and an associate professor in the School of Behavioral and Brain Sciences at the University of Texas at Dallas, told Business Insider that the latest study is an important area for future research, and said the links the study authors found “between death from hypertension and years of marijuana use does indicate a relationship” between the two things.
Still, Filbey said the study has important limitations, and said future studies should aim to also look at how factors like other substance use, BMI and other factors that may affect heart health could play a role in the outcome as well.
A new study suggests marijuana is linked with a threefold risk of death from hypertension. Here's what you should know about cannabis and your heart.
How does cannabis affect blood pressure?
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- Does marijuana lower or raise blood pressure?
- What are the cardiovascular effects of cannabis?
- Weed and blood pressure medication
- Other effects of weed on blood pressure
Since smoking a joint can lead to a relaxing high, you might wonder about cannabis use and its effect on blood pressure. We know that weed can make your eyes red , but does it also raise or lower blood pressure, or does it not have any effect at all? If you have high blood pressure, is marijuana safe to consume?
Here we’ll address how smoking weed, including medical marijuana, could factor into your blood pressure levels.
Does marijuana lower or raise blood pressure?
To answer this question, we should focus on two of the primary cannabinoids present in cannabis : cannabidiol (CBD) and tetrahydrocannabinol (THC). Both may exert an influence on blood pressure levels.
Dr. Bonni Goldstein, a medical adviser to Weedmaps and the director of Canna-Centers in Lawndale, California, outlined the potential effects of THC on blood pressure:
“THC can affect blood pressure depending on the dose, the route of administration, a person’s experience with THC, and a person’s underlying health. Healthy volunteers that took THC had an increase in heart rate and decrease in blood pressure. In studies where people used THC while lying down, they had elevated blood pressure. When they stood up, their blood pressure dropped and they experienced low blood pressure.”
These sudden drops in blood pressure, also known as white outs or green outs, may indeed be linked to cannabis use. Dr. Melanie Bone, a board-certified OB-GYN and cannabis specialist who practices in West Palm Beach, Florida, told Weedmaps that “cannabis may cause a drop in blood pressure on standing — known as postural hypotension.” This type of drop in blood pressure is not desirable, as it can cause vertigo and even fainting. So, when we talk about “lowering blood pressure,” we do not necessarily consider that effect beneficial to health.
Both THC and CBD may lower blood pressure in different ways. However, neither CBD nor THC should be considered a medical treatment for high blood pressure. Photo by: Gina Coleman/Weedmaps
And how does CBD affect blood pressure? The consensus is that CBD tends to relax the blood vessels and decrease anxiety, which ultimately leads to a lowering of blood pressure. This type of blood pressure reduction is more favorable, as it is associated with decreased levels of anxiety. Both THC and CBD may lower blood pressure in different ways. However, based on available research, neither CBD nor THC should be considered a medical treatment for high blood pressure.
What are the cardiovascular effects of cannabis?
Another frequently asked question about cannabis and cardiovascular health is: can weed cause a heart attack?
First, let’s again distinguish between the cannabinoids THC and CBD. For example, CBD oils containing trace levels of THC may have very different effects than smoking a high-THC strain of marijuana. Various studies have indicated that THC may have detrimental effects on cardiovascular health, whereas CBD could be helpful to the heart.
Goldstein added, “CBD does not appear to have the same risks for the heart as THC and in fact, appears to be somewhat cardioprotective.” To support this assertion, Goldstein cited a 2010 study published in the Journal of the American College of Cardiology in which researchers concluded that CBD has therapeutic potential in treating complications of diabetes, as well as some cardiovascular disorders. Most notably, CBD could reduce inflammation, a condition that can ultimately damage the blood vessels, arteries, and vital organs. So, if you apply CBD oil to your skin or swallow a few tablespoons, the impact could differ greatly than if you smoked a blunt.
To this point, there is some research that suggests smoking THC could directly or indirectly lead to a heart attack. One 2019 study titled “The Cardiovascular Effects of Marijuana: Are the Potential Adverse Effects Worth the High?” and published in the Journal of the Missouri State Medical Association showed that some people experienced a heart attack within an hour of smoking cannabis.
Bone, however, argued, “On careful study, many of the patients also smoked cigarettes and were obese, making it hard to draw absolute conclusions. Also, the observations were made on cannabis of unknown origin, not cannabis from a dispensary.” The fact that the cannabis did not come from a registered dispensary is significant, as there is no available lab testing to determine what other compounds may have been present.
The bottom line is that there have been studies demonstrating a questionable association between smoking weed and having a heart attack, and more research is necessary.
Weed and blood pressure medication
You might also be wondering, what if you’re smoking weed while taking blood pressure medication? Will there be an adverse reaction? If you are smoking THC-rich cannabis and taking medication for high blood pressure, the answer is that there could be.
Goldstein explained, “Smoking cannabis can be harmful for those with heart disease or hypertension since the smoke contains carbon monoxide. This gas binds to the hemoglobin in red blood cells, displacing oxygen off of the red blood cells which results in less oxygen going to the body’s tissues, including the heart. People with heart disease or high blood pressure should avoid smoking.”
Instead, Goldstein recommends other methods of cannabis use, such as sublingual tinctures or edibles, which she says are safe to use if someone is on blood pressure medication. Further, Bone stressed that people who use cannabis and are on blood pressure medications need to be mindful of the possibility of an interaction with other prescription medications. This means monitoring blood pressure and reporting any dizziness to your doctor, who can adjust your dosages accordingly.
People who use cannabis and are on blood pressure medications need to be mindful of the possibility of an interaction with other prescription medications. Photo by: Gina Coleman/Weedmaps
In particular, the blood thinner warfarin was shown in a 2017 study published in the journal Epilepsy & Behavior Case Reports to interact with cannabidiol (CBD) in certain epileptic individuals . In line with Bone’s advice, researchers concluded that patient lab work should be monitored closely.
While it is possible for warfarin and other medications to interact with cannabis, there are no guarantees, and the 2017 study focused on patients with epilepsy rather than on the general population. As Dr. Bone reported, “In my private practice, I have not encountered a significant negative interaction between blood pressure medication and cannabis.”
Other effects of weed on blood pressure
There may be other effects of marijuana on blood pressure that health practitioners have yet to discover. All potential effects depend on the individual’s existing health problems, especially co-morbid conditions such as diabetes and obesity.
Can people without these conditions safely indulge in marijuana? A healthy individual’s body may appear as a well-oiled machine, but Bone disputes that analogy, pointing out that, “Unlike a car, where we replace the brakes or tires, the heart never gets a vacation and the blood vessels need to keep working forever. And the nervous system, which directs the show like a conductor, is on duty 24/7.”
Moderation, then, may be key in integrating a cannabis regimen into your healthcare plan. Consult with your physician before you begin using cannabis or CBD products and discuss any medications you are currently taking.
Learn how cannabis affects blood pressure and what questions you should ask your doctor before starting a regimen.