Cannabis and its impact on high blood pressure
Given the increasing prevalence of hypertension at a time when states are liberalizing cannabis laws, people want to know: what are the effects of cannabis on blood pressure? Does it lower blood pressure? The answers largely depend on who you ask or what study you read.
One in three adults in the U.S. has high blood pressure, a condition known as hypertension. Left unmanaged, it can lead to cardiovascular disease, which is characterized by an increased risk of stroke, heart attack, and even heart failure. A number of factors, including poor diet, stress, physical inactivity, alcohol, and tobacco use increase the risk of developing hypertension.
Some of the effects of cannabis on blood pressure, particularly the acute effects, are well understood and documented. However, research studies describing other effects, especially long-term adverse or positive effects, are limited, and often plagued by poor study design or the fact that findings from animal studies don’t always neatly transfer to human subjects.Further, many research findings are highly generalized, focusing on THC while neglecting consideration of the numerous other cannabinoids. Logically, a cannabis strain high in the psychoactive cannabinoid THC would yield different results from a strain high in the largely non-intoxicating cannabinoid CBD.
Perhaps most frustrating, published studies investigating differences between consumption methods – such as the effects of smoking cannabis versus ingested edibles – are essentially nonexistent.
With these limitations in mind, here is what we do know.
Short-Term vs. Long-Term Effects of Cannabis Consumption
Does cannabis raise blood pressure? Studies suggest shortly after consumption, occasional users will experience a mild to moderate dose-dependent increase in blood pressure and heart rate, followed by a modest hypotensive effect (a decrease in blood pressure). The onset of peak effects like elevated heart rate and blood pressure occur within 10 to 15 minutes after consumption.
Users can develop a tolerance to the initial effects over a period of a few days to weeks, and repeated use has been associated with lowered heart rate and blood pressure immediately following consumption. Anecdotally, many people report that cannabis helps them maintain healthy blood pressure levels, an effect supported by research studies.
Here’s an interesting piece of “non-trivial trivia” you can use to impress friends at your next cannabis-inspired intellectual discussion: posture during consumption may influence blood pressure. Suppose you’re sitting or lying on your couch – your blood pressure will temporarily increase immediately following consumption. Once you stand up, blood pressure will drop. In fact, if you stand up suddenly, blood pressure could drop significantly enough to induce enough lightheadedness to make you feel like you’re about to faint (don’t worry, it’s unlikely you’d actually pass out).
On the other hand, if you’re standing up when you imbibe, blood pressure may decrease without ever initially increasing. However, there isn’t a lot of published data verifying this effect. (If you’ve done your own comparative measurements, feel free to share in the comments section below!)
Cannabis and Stroke or Heart Attack
As far as serious adverse risks, a UC San Francisco longitudinal Coronary Artery Risk Development in Young Adults (CARDIA) study analyzing data from 3,617 African American and Caucasian adults over a 15 year period found there was no long-term causal link between cannabis consumption and the risk of heart attack or stroke.
However, there are a limited number of animal studies and human case reports that suggest a link between acute intoxication and stroke or heart attack. But, these findings have been called into question by a 2006 report published in the Forensic Science, Medicine and Pathology Journal: “Despite the drug’s extreme popularity, reports of cannabis-related stroke and myocardial infarction are so rare as to still be reportable.”