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.
Does Medical Marijuana Lower Blood Pressure?
The number of Americans at risk of heart attack and stroke has increased substantially over the last decade. According to statistics released from the American Heart Association, nearly half of all adults in the United States have high blood pressure.
Alarmingly, the rising prevalence of hypertension has coincided with the relaxation of U.S. state marijuana laws, raising questions and concerns among both health professionals and the public. People want to know, does marijuana lower blood pressure? Or does marijuana raise blood pressure? And, what are the long-term effects of cannabis on cardiovascular health?
An estimated 2 million Americans with an established cardiovascular disease currently use or have used marijuana. In this article, we’ll review the current evidence on the acute and chronic cardiovascular effects of marijuana.
What is Hypertension?
Hypertension (aka high blood pressure) is when the force of blood flowing through your arteries is consistently too high. When a person has hypertension, their heart must work harder to pump blood around the body, which contributes to hardening of the arteries. Left unmanaged, hypertension can lead to cardiovascular disease, which is the leading cause of death worldwide, claiming nearly 18 million lives per year. Cardiovascular disease includes heart attacks, strokes, and heart failure.
Blood pressure readings contain two measurements: systolic blood pressure (the first number) and diastolic blood pressure (the second number). Systolic blood pressure measures the force on the artery walls when the heart is contracting. Whereas, diastolic blood pressure is when the heart relaxes between beats.
Blood pressure readings below 180/20 mmHg are considered normal and within a healthy range. However, if your systolic blood pressure rises above 130 mmHg or your diastolic blood pressure rises above 80 mmHg, you have Stage 1 Hypertension, according to the American Heart Association. Once your blood pressure reaches 140/20 mmHg, you’ve hit Stage 2 Hypertension—any higher than you’ve entered Hypertension Crisis.
What Causes Hypertension?
Several factors contribute to the development of hypertension, including obesity, stress, chronic alcohol consumption, physical inactivity, and tobacco use. However, the association between hypertension and marijuana consumption is less clear, primarily due to the restrictions on human trials and the complexity of the drug itself. Marijuana contains over 100 active compounds, called cannabinoids, and each strain contains a unique concentration of cannabinoids. Therefore, the effects differ depending on the product.
Cannabinoids exert their effects through the endocannabinoid system, which consists of endocannabinoids and cannabinoid receptors. Cannabinoid receptors, particularly CB2 receptors, are present on the myocardium (heart muscle), coronary endothelium (surface of arteries), and vascular endothelium (surface of veins).
Specific cardiovascular effects, particularly acute effects, are well understood and extensively documented. For instance, we know that tetrahydrocannabinol (THC), the main psychoactive cannabinoid, temporarily stimulates the sympathetic nervous system. However, research studies investigating the long-term effects of marijuana use on cardiovascular health are limited and often plagued by poor study design or animal models that don’t necessarily transfer to humans.
Also, most studies fail to differentiate between consumption methods, such as smoking marijuana, compared to applying a topical ointment. Frustratingly, there’s also a high degree of generalization, with studies often focusing on THC and neglecting the role of cannabidiol (CBD). Lastly, very few studies distinguish between synthetic and plant-derived cannabinoids. With such limited research, it’s difficult to make concrete conclusions on the link between marijuana and hypertension. However, here is what the current research literature says so far.
Acute Effects: Marijuana and Blood pressure
According to Harvard Health, research has consistently shown that marijuana temporarily raises heart rate and dilates blood vessels, causing a modest dose-dependent increase in blood pressure. Together, these actions force the heart to pump harder, which can be dangerous for people with heart disease.
Research published in Cardiology in Review, suggests that the risk of heart attack is up to four times higher during the first 60 minutes of smoking marijuana. While this does not pose a threat to healthy people, it should be a red flag for people with a known heart condition. Other studies have shown a link between marijuana and atrial fibrillation, a common heart rhythm disorder.
To investigate the above claims, medical researchers at the Society of General Internal Medicine recently reviewed the acute effects of THC of several cardiac parameters, including heart rate and blood pressure. Their analysis included six clinical trials on blood pressure, after excluding studies with animal models and less than 20 participants.
In one randomized controlled trial (RCT), low concentrations of THC (3.55%) caused a drop in systolic blood pressure when smoked or injected. Another clinical trial of more inferior quality also found a decrease in systolic blood pressure at similar concentrations.
Three of the four remaining studies found no significant effect, while one study found an increase in blood pressure. These findings suggest there is insufficient evidence to claim marijuana has any specific acute effects on blood pressure. The analysis also included 14 clinical trials, all of which found that marijuana was associated with tachycardia or increased heart rate.
Chronic Effects: Marijuana and Blood Pressure
Smoking marijuana carries many of the same cardiovascular health hazards as smoking tobacco. A new study, published in the American Journal of Health Behaviour, analyzed data from the 2005-2014 National Health and Nutrition Examination Surveys.
In total, 10,709 American adults were included in the retrospective study. Researchers defined marijuana use as “never” (no lifetime use), “past” (lifetime, not in the past 30 days), and “current” (at least once in the past 30 days). After adjusting for covariables – such as alcohol, tobacco, and other drug use – heavy users (defined as daily) were reportedly twice as likely to have high blood pressure than “never” users. However, no significant differences in blood pressure existed between other categories. These results suggest that heavy marijuana use may contribute to the development of hypertension, while occasional use is unlikely to impact blood pressure in the long term.
In another study, published in the American Heart Association Journal in 2020, researchers examined the effects of THC on the blood pressure of almost 3000 veterans, of whom 800 were current cannabis users and 2098 current non-users. Smoking was the predominant form of consumption (90%). After adjusting for covariables, cannabis users had slightly higher systolic blood pressure. Interestingly, however, current users were less likely to be on medication for high cholesterol (statins), blood clotting (anticoagulants), and an irregular heartbeat (beta-blockers). However, this could be a reflection of health-seeking behaviors. They also had a lower body mass index (BMI), which is a well-established protective factor against heart disease.
Is Marijuana Good for High Blood Pressure?
If you currently suffer from hypertension, you may be wondering whether marijuana can help lower your blood pressure. While the body’s endocannabinoid system plays a key role in regulating critical physiological processes, including cardiovascular function, research is yet to determine a definitive answer.
Animal models suggest that anandamide – the body’s own version of THC– may relax blood vessels and thus help lower blood pressure. But anandamide appears to be triphasic, meaning it produces different effects under different conditions. For instance, under some circumstances, anandamide has a stimulatory effect leading to increased blood pressure.
More rigorous human trials are needed to make any claims about the effectiveness of marijuana as a long-term treatment for hypertension.
Heart Disease? Best to Avoid Marijuana
Smoking marijuana carries many of the same cardiovascular health hazards as smoking tobacco, which is a major cause of heart attack, stroke, and heart failure. Until we have a clearer picture of the connection between marijuana and heart diseases, people with a heart condition or at risk of heart attack or stroke due to hypertension should consider avoiding smoking marijuana of any kind. These recommendations are in alignment with Harvard Health.
Many Americans suffer from hypertension. Is there a link between marijuana and blood pressure and should those with high blood pressure use marijuana?