Marijuana and blood pressure

Does marijuana help high blood pressure?

Cannabis has been suggested as a potential treatment for hypertension, but there are concerns that it might actually exacerbate the condition. 

The endocannabinoid system is involved in the regulation of blood pressure, so it is possible that manipulating this system could prove therapeutically helpful for the treatment of hypertension — or it is possible that it may worsen it. Unfortunately there is very little research on using cannabis for this purpose, and what research we do have is both limited and conflicted. 

While scientists don’t have enough data to recommend cannabis for this condition, they do recommend continued research into whether cannabis, and CBD in particular, might be able to help. 

How Cannabis Works on Hypertension

The endocannabinoid system (ECS) exists in all vertebrates and helps regulate crucial functions such as sleep, pain, and appetite. The human body produces its own cannabinoids, which modulate and activate its various functions. But as its name suggests, the endocannabinoid system can also be modulated and activated by cannabinoids found in the cannabis plant. Because the entire system was only discovered in the past 30 years, scientists still have much to learn about the myriad ways cannabis affects the human body.

As it turns out, this system is also involved in regulating the cardiovascular system. Researchers have found that the endocannabinoid system plays a key role in the adjustment of cardiovascular activity — and, in particular, strongly affects hypertension. 

Activation of this system’s various receptors with endocannabinoids (such as anandamide) in animal studies has led to noticeable and clinically significant changes in cardiovascular effects such as the increase or decrease of blood pressure, heart rate, blood vessel constriction, inflammation, and oxidation. So it is clear that the endocannabinoid system impacts our cardiovascular functioning. 

In addition, studies have found that the endocannabinoid system is overactive in arterial, pulmonary and portal hypertension. Still, it is relatively unclear from the research whether this elevation in endocannabinoid activity is playing a protective role, or a harmful one. This is in part because endocannabinoids can cause blood vessels to both widen and contract in different contexts — both increasing and decreasing blood pressure. These actions might be beneficial or harmful for different types of hypertension, so the implications of these effects can go both ways. 

While researchers have a long way to go when it comes to understanding these impacts, some suggest that targeting this system with cannabinoid-based treatments could be an effective way to treat hypertension. Still researchers caution that more research needs to be done to better understand the long term implications of cannabinoids on the cardiovascular system, as well as their potential interactions with food and other medications that lower blood pressure. 

Medical Studies on Cannabis and Hypertension

While we have clear evidence that cannabinoids impact our cardiovascular activity via the endocannabinoid system, we need to look to the research on humans to get a real picture of how it impacts hypertension. After all, animal studies give us a hint of how things might work for humans, but can sometimes point us in the wrong direction. 

When it comes to the medical studies on marijuana and high blood pressure, our data is fairly limited — and what we do have is sometimes conflicted. Some studies report that acute cannabis use causes an increase in heart rate but no significant changes in blood pressure, and that chronic cannabis use can lead to long lasting decreases in blood pressure and heart rate. This could indicate a long term helpful role in reducing hypertension. Still, other studies suggest that the increased heart rate from cannabis consumption comes along with temporary increases in blood pressure. 

To add to this confused picture, survey-based studies looking at smoking marijuana and blood pressure have also brought back conflicting results. An alarming study from 2005 found that those who had ever used cannabis (even just once) were more than three times more likely to die from hypertension than those who had never used the drug. Still, it’s important to note limitations of this survey. For one thing, many people underreport use of other illicit drugs, which might account for these issues. This survey also didn’t look at the frequency or dose of cannabis used, so it was limited by those factors. 

Despite this frightening study, another survey-based study from 2016 found no relationship between cannabis use and hypertension. While they did find recent cannabis use was tied to an increase in systolic (but not diastolic) blood pressure, they found no associations between chronic cannabis use and blood pressure at all. Cannabis use was not associated with hypertension or prehypertension even when it was used regularly throughout someone’s life. 

In addition, a review of previous literature on cannabis and cardiac health found limited evidence that cannabis use was tied to an increased risk of ischemic strokes, but did not report any link to hypertension. 

But in another study on hypertension and cannabis, researchers found cannabis withdrawal could be a potential risk factor. In this study, researchers monitored blood pressure from heavy cannabis users before and after a period of abrupt abstinence from cannabis. These chronic cannabis users all had normal blood pressure while using cannabis but after suddenly stopping the drug, some participants saw their blood pressure skyrocket into hypertensive ranges. Researchers on this study pointed out that these changes could be directly related to the withdrawal process, or might be a secondary symptom related to factors such as the anxiety that accompanies withdrawal. 

Interestingly, this study was on mostly older and African-American patients — two groups at risk for hypertension. This led researchers to wonder whether cannabis might be offering a protective effect from hypertension, which is removed when cannabis is no longer taken; or whether the spike in blood pressure is simply a withdrawal effect from stopping cannabis. More research which looks at blood pressure before beginning cannabis use (as well as during and after) is needed to disambiguate the cause of this hypertension. 

Most of the participants (69%) did not see raises in blood pressure significant enough to be considered hypertension, so this is likely to affect a minority of cannabis users. Still, those with preexisting cardiac issues could face problems during withdrawal. The authors suggest that those with cardiac risk factors, who are considering stopping cannabis, should do so under physician observation to ensure blood pressure levels stay in a safe range.

Can CBD help with high blood pressure

While studies on cannabis in general present conflicting results about its relationship to blood pressure, this could be in part because cannabis has many potential active ingredients. While THC is known to cause cardiac effects like temporarily increasing heart rate, and in some cases blood pressure, CBD, another cannabinoid in cannabis, can actually reduce this effect from THC when they are taken together. On its own, CBD is known to reduce blood pressure, making it an attractive possibility for managing hypertension. Some studies point to it as a potential hypertension treatment to investigate, but much research needs to be done to confirm its efficacy.  

Potential side effects of cannabis use

Scientists have yet to conclude that cannabis is a safe option for those with hypertension, and we have very little data on what side effects are common for those with that condition. But given what we know about cannabis’ potential to impact cardiovascular activity, it is possible it could cause increased or decreased blood pressure and could increase your risk of other cardiac events like ischemic strokes. 

If you are already using cannabis and have hypertension (or have had it before), or have other cardiac risk factors, you could also be at risk for increased blood pressure during withdrawal.