Fraser Horton
Fraser Horton
Last Updated on February 25, 2021

High blood pressure is one of the most common causes of (preventable) heart disease and stroke. Research reveals that in 2020, 32.5% of the population in the United States was diagnosed with high blood pressure by a healthcare professional. However, there are many others who also suffer from this condition without being officially diagnosed and this puts them at an increased risk of complications.

In 2017, the official blood pressure guidelines were unanimously modified by the American College of Cardiology and the American Heart Association. Previously, blood pressure of 140/90 and above was considered high, now it’s at 130/80 and above. This change altered the numbers of people with high blood pressure in the USA significantly, categorizing more people as having hypertension and in need of treatment.

Following the relaxation of the federal laws on weed, medical marijuana is being increasingly used for the treatment of various conditions, making people wonder if it can be used for the treatment of high blood pressure as well. In fact, as of 2020, 2 million people in the US with a diagnosed cardiovascular disease either use or have used marijuana.

In this article, we’ll discuss this condition and the acute and chronic effects of marijuana use on cardiovascular function.

What Is Hypertension?

Blood pressure is measured as the force of the blood flow pressuring against the artery walls. High blood pressure, also called hypertension, is when this force is consistently too high. This means that the heart must work consistently harder in order to pump blood, which can gradually lead to damage and weakening of the arteries.

Blood pressure is measured in millimeters of mercury (mmHg). Systolic blood pressure (the first number on the monitor) refers to the force of blood in the arteries when the heart pumps blood, whereas diastolic blood pressure refers to when the heart rests in-between the heartbeats. Normal blood pressure should be below 130/80mmHg. Anything above, and the individual is considered to be entering the beginning stages of hypertension.

High blood pressure is often undetected because many individuals don’t have any symptoms and are primarily diagnosed during a regular checkup. When symptoms do appear, it means that the condition has gotten to a point where it needs medical attention.

Left untreated, hypertension can lead to serious health problems, like a risk of heart attack, stroke, heart failure, and other cardiovascular diseases.

Risk Factors and Causes of Hypertension

Some of the main causes of high blood pressure include obesity, poor diet, stress, sedentary lifestyle, and chronic alcohol and tobacco use, all of which increase the prevalence of this condition.

Some of the risk factors include:

  • Age – Hypertension is known to be more prevalent with age, typically over 65;
  • Weight – Obese and overweight individuals are more likely to develop hypertension;
  • Family History – People with a family history of hypertension are at a higher risk;
  • Lifestyle – Sedentary lifestyle where individuals are physically inactive contributes to less compliant blood vessels, which causes the heart to work harder, thereby leading to a higher blood pressure;
  • Ethnicity – People of African heritage are more prone to developing hypertension at a younger age than Caucasians.

The Cardiovascular Effects of Cannabis

Marijuana is a chemically complex plant that contains hundreds of active ingredients that include cannabinoids, terpenes, and flavanols, which work together to produce the unique effects that weed is known for.

The cannabinoids in weed interact with the body’s endocannabinoid system, which is an organized network of endocannabinoids and cannabinoid receptors. The endocannabinoid system plays an active role in many bodily processes, including the cardiovascular system.

Out of all the cannabinoids, the main two, and most researched ones, are CBD (cannabidiol), the non-intoxicating cannabinoid, and THC (tetrahydrocannabinol), the cannabinoid that produces the psychoactive effects. Each cannabis strain has a different ratio not only of these two cannabinoids, but also of the others. This allows for different strains to produce their unique effects, giving cannabis users a wide variety to choose from.

The short-term cardiovascular effects of marijuana have been well-researched. It’s been established that THC temporarily affects the sympathetic nervous system, until the effects of smoking cannabis, for example, wear off.

However, there is no satisfactory research on the long-term effects of cannabis use on the cardiovascular system. This is mostly due to the study design, or the trials being animal-based, which can’t really translate well to humans. Additionally, the method of consumption is often not taken into account, including that most studies largely focus on THC, while CBD is overlooked.

Let’s see what the available research regarding marijuana and high blood pressure shows.

Does Marijuana Raise Blood Pressure?

Time and time again, research has shown that weed temporarily raises the heart rate and dilates the blood vessels, which temporarily elevates the blood pressure. This effect is largely dose-dependent and happens when the body initially comes into contact with weed. Nonetheless, it can be risky for people with existing heart disease.

In relation to this, a study published in Cardiology in Review proposes that the risk of a heart attack is multiple times higher within the first hour of smoking marijuana. These findings wouldn’t apply to people without a heart condition, but for those who have been diagnosed with a heart condition, it can be dangerous. Additionally, a systematic review has found a link between smoking marijuana and atrial fibrillation, which is a fast and irregular heart rhythm.

One clinical trial that lasted from 2005-2012 was following the cannabis use of 12,000 participants and their blood pressure during the seven-year span. The final results were published in 2016 in the Journal of Hypertension and they indicated that the participants who used marijuana within the previous month had a somewhat higher systolic blood pressure than non-users

Similarly, a recent study published in the American Heart Association Journal has examined the effects of THC on blood pressure on 3,000 participants of which 800 were active marijuana users, while the rest were non-users. The findings of this study indicated that the marijuana users had a slightly higher systolic blood pressure, but, they also had a lower prevalence of diabetes and hyperlipidemia (high concentration of fats in the blood). However, this doesn’t necessarily have to be connected to their cannabis use.

Bottom Line – Better Skip Marijuana Until There’s More Research

If you’re suffering from hypertension, using marijuana may not be the best choice for you, primarily due to the lack of firm research material on its long-term effects. Given that current research on the short-terms of marijuana use indicates that it raises blood pressure, you may put yourself at a higher risk. Therefore, it may be best to skip it for now, or at least until there’s more research on its effects on hypertension.

Additional Sources

Alshaarawy, O., & Elbaz, H. A. (2016). Cannabis use and blood pressure levels: United States National Health and Nutrition Examination Survey, 2005-2012. Journal of hypertension, 34(8), 1507–1512. https://doi.org/10.1097/HJH.0000000000000990

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