There are two major ways that cannabis affects the heart. First, cannabis can lower blood pressure. Second, the active compounds in the herb can cause increased heart rate. These two phenomena are somewhat opposite of each other. Perhaps more often than not, an increased heart rate is associated with higher blood pressure. So, what exactly does cannabis do to your heart? Are these two things good or bad? Unfortunately, the answer to this question is not simple.
What does cannabis do to your heart?
Almost immediately after consuming cannabis, the herb has an effect on your blood pressure. Though some research suggests that blood pressure fluctuates shortly after consumption, the herb is generally considered a potent vasodilator.
This is excellent news for those with high blood pressure or conditions like glaucoma. In fact, the ability of cannabis compounds to open blood vessels is why the herb causes red eye and dilates pupils.
Cannabis can also increase your heart rate by two times for up to three hours after consumption. However, this effect will vary significantly from person to person. In some, heart rate may only increase by 20%. This pounding heart can make some people feel anxious, and it puts you at greater risk of having a heart attack.
However, the chances of this outcome are quite slim. Elderly folk and those with pre-existing conditions such as obesity, tobacco consumption, and preexisting heart conditions may have trouble with the racing effects of cannabis. Early rodent models suggest that this heart-racing effect is more pronounced in new consumers, but decreases with tolerance.
Coffee, espresso, and energy drinks have a similar effect on heart rate. Though, these substances also increase blood pressure as well. One 2006 study suggests that caffeine also put you at a greater risk of having a heart attack after consumption. Though, also like cannabis, these effects are highly debated. In 2007, another study came out countering these claims.
Is cannabis good for your heart?
At this point, there is no way to tell whether or not cannabis compounds have any firm benefit for the heart. However, there is some investigation into nonpsychoactive cannabidiol (CBD) as a potential therapy for heart failure.
The girth of potential for CBD was highlighted in a 2013 review published in the British Journal of Pharmacology. As the review explains, in rodent models, CBD has successfully reduced vascular tension, a condition that causes unnecessary strain in blood vessels. It has also been shown to protect the arteries from damage from glucose (sugar).
The same review articulated that cannabis reduces the general inflammation associated with diabetes. Inflammation of the blood vessels puts significant strain on the heart.
Overall, in vitro evidence suggests the cannabinoid may be an important tool for protection against cardiomyopathy associated with diabetes.
Additional research suggests that the endocannabinoid system (ECS) plays a role in the development of certain heart conditions. The ECS is a vast messaging and regulatory network in the body, playing a part in neuroprotection, stress control, metabolism, immunity, and many other vital body functions.
The active compounds in cannabis engage with this system to produce therapeutic effects. A rodent study published in the International Journal of Cardiology found that deficiencies in the endocannabinoid system possibly contribute to chronic heart failure.
Mice that had lower levels of cannabinoid 1 receptors (CB1) were less likely to survive and suffered more heart abnormalities than mice with healthy CB1 expression.
CB1 receptors are the special cell sites where compounds like THC, the primary psychoactive in cannabis, engage the body. The study authors write,
In this study, we found that CB1 deficiency contributed to the exacerbation of chronic cardiac remodeling… revealing a new role of CB1 in pathophysiology of [chronic heart failure].
While this study is merely a preclinical observation, this finding provides some interesting evidence that cannabinoid medicines may be useful in certain types of heart conditions.
Though, only substantial human trials will be able to determine whether or not this is a viable path for future patients.
Is cannabis bad for your heart?
Not all researchers are optimistic about the effects of cannabis on your heart. Some studies suggest that cannabis may be a trigger for heart conditions in young people.
For example, a study from the French Addictovigilence Network analyzed 1979 reports that were sent in about negative reactions to cannabis.
35 of the nearly 2,000 were related to cardiovascular complications. 16 of the 35 cases had a known family or personal history of heart disease, though family data was not available for all cases.
The study ultimately found that between 2006 and 2010, rates of heart problems where cannabis was present increased from 1.1 percent to 3.6 percent. 21 (60 percent) participants also smoked tobacco. Two participants were classified as overweight, one as obese, yet BMI was only recorded for 11 of the 35 cannabis consumers. 22 of the participants did not have complete toxicology reports.
These numbers are important. While this study found a rise in heart-related incidents, it does not adequately rule out confounding risk factors like tobacco consumption and obesity. This small study does little to prove causation between cannabis and cardiovascular complications.
2016 research published by the American Heart Association, Inc. suggests that young men are more likely to experience a very particular heart problem after cannabis. A research team from the St. Luke’s University Hospital Network found that young, male cannabis consumers had higher rates of stress cardiomyopathy.
Stress cardiomyopathy is a temporary weakening of the heart muscles that is often caused by things like intense stress and grief. Using Nationwide Inpatient Data, the researchers analyzed hospital data from 33, 343 patients with the condition. Only 210 patients (1 percent) used cannabis.
The researchers found that, while stress cardiomyopathy is often associated with older women, the samples from the cannabis group were largely younger men. These young people had fewer of the standard risk factors than the average, non-consuming group.
This lead the researchers to conclude that cannabis is an independent risk factor for certain types of heart conditions.
However, retrospective studies like this one are again limited. Men are more likely to consume cannabis than women, possibly skewing the gender aspect of this research. There is also little information about the type of cannabis consumed, dosage, and other potential confounding lifestyle and toxicology factors.
It is well-known that tobacco increases the risk of cardiovascular complications like stroke, hypertension, and heart attack.
Should I smoke cannabis if I have a heart condition?
What little evidence is available suggests that smoking high-THC cannabis is probably not the best thing you can do if you have a heart condition. However, high-quality studies on cannabis and heart disease are few and far between.
What is known for sure is that the herb does increase heart rate, which could be worrisome for those who are at risk of heart failure.
As the studies above suggest (as imperfect as they are), the herb may cause problems for teens and young people with preexisting heart weakness. Everyone with a family history of heart disease or other heart concerns should be mindful of their heart when consuming.
Those who tend to experience a racing heartbeat after cannabis may want to consider switching strains. Strains higher in CBD and lower in THC may help address the issue and make the entire experience more comfortable. However, there is no concrete information about how many people may be at risk for cardiovascular complications after cannabis.
It goes without saying that anytime you are concerned about your heart, seek medical attention. The information in this article is for educational purposes, and should not be used in place of medical advice. You are encouraged to talk to a trusted medical professional for more information on how cannabis may impact your unique heart