Every third American adult has high blood pressure, and only half of those with hypertension have the condition under control. When blood pressure is above the norm, the risks for heart diseases and stroke increase significantly.
Some of the effects of marijuana on blood pressure are well understood and documented. We have analyzed the most substantial studies and reviews on the link between cannabis and high blood pressure.
Blood pressure is a measurement of the force exerted by the blood on the walls of arteries. Hypertension, or high blood pressure, is a disease in which the blood pressure is 140/90 or above most of the time. If the blood pressure numbers are above normal but below 140/90, it is called pre-hypertension.
High blood pressure does not cause severe symptoms—a patient may experience headaches, vertigo, or altered vision, which, for example, also occurs in case of anxiety. However, if it is left untreated, hypertension can lead to cardiovascular disease characterized with an increased risk of heart attack, stroke, vision loss, and even heart failure.
High blood pressure results from a complex of environmental factors and genetics. If the condition has no identifiable cause, it is called primary. Some people have hypertension caused by other diseases, such as sleep apnea, kidney problems, and certain defects in blood vessels. Obesity and drug/alcohol use can also increase the risk of the development of hypertension.
Changing lifestyle habits is a critical step in preventing and treating hypertension. Among things you can do, there are turning to a healthy diet rich in fiber and potassium, losing excess weight, exercising regularly, quitting smoking and alcohol, and reducing stress.
Treatment always starts with lifestyle modification, but if the results are unsatisfactory, doctors prescribe medication. There are many different medicines to manage blood pressure, although they cannot cure the condition. The Joint National Committee recommends thiazide-type diuretics as the first-line therapy for most patients because they are generally well-tolerated and less expensive than other anti-hypertensive drugs. Other most commonly used classes of drugs include angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), beta-blockers, and calcium channel blockers. Anti-hypertensive therapy usually involves the use of two or more kinds of medication—it increases the likelihood of achieving blood pressure goals in a more timely fashion.
The possibility of using cannabis as an antihypertensive drug was first considered more than forty years ago. However, no cannabinoid-based medications have been approved since then. Some of the effects of marijuana on blood pressure are still not fully determined, and much controversy remains. Research results demonstrate that marijuana has some effects on the symptoms and complications of hypertension.
The plant is known to reduce high blood pressure to normal levels with regular use and to maintain normal levels with continued use in some cases. In 2004, researchers at the National Institutes of Health reported about the important role of the body’s internal cannabinoids system in regulating blood pressure. The study on rats demonstrated that anandamide—the body’s naturally occurring version of THC—and other endocannabinoids might suppress hypertension and normalize blood pressure.
A year later, in their review, scientists at the same institution wrote that hypertension could be reversed or inhibited by certain CB1 antagonist. They also reported that endocannabinoids were found to profoundly suppress cardiac contractility in hypertension. These findings led some experts to suppose that the manipulation of the endocannabinoid system may offer a novel therapeutic approach in a variety of cardiovascular conditions.
A growing body of studies show that anandamide lowers blood pressure by relaxing blood vessels and allowing blood to flow more freely.
In 2005, German scientists found coronary vasodilator effects of cannabinoids in rats. They injected anandamide, THC, and certain CB2 antagonists into the rat's isolated heart in order to investigate the effects of various cannabinoids in spontaneously beating Langendorff-perfused rat hearts. According to the researchers, cannabinoids including anandamide elicited coronary vasodilation and a secondary increase in contractility via CB1 receptors and potassium channels.
The vasorelaxant effects of synthetic cannabinoids and endocannabinoids are complex and display tissue and interspecies differences.
Obesity. People with excess weight often have problems with blood pressure. THC was found to stimulate the production of a hormone called ghrelin that plays an important role in metabolism and lowering insulin levels.
Anxiety. Stress and anxiety can lead to dozens of physical and psychological problems, including high blood pressure, cardiovascular conditions, and clinical depression. Numerous studies showed marijuana to reduce anxiety levels and relieve anxiety-related disorders, from irritability to insomnia to heart palpitations.
However, there is a controversy in the findings received from animal and human studies. A 1997 study did not confirm the link between cardiotoxicity and cannabinoids in humans. Also, according to a 2006 study done by the Foundation for Medical Research at Geneva, the administration of synthetic cannabinoids have been shown to lower blood pressure in animals but have not been associated with cardiotoxicity in humans.