The danger of tobacco use as a cause of heart diseases is well-known. Long-term marijuana use may be dangerous from a neurocognitive standpoint, but there is little evidence available regarding its impact on heart and blood vessels. A recent WHO report, based on all the significant research in the field for the past two decades, explains the health consequences of cannabis use, particularly its effects on the cardiovascular system.
With more and more people supporting the idea of both legalizing marijuana for medicinal purposes and legally using it as a recreational drug, it is more important than ever to obtain solid scientific data on the potential health impact of cannabis use.
The more recreational weed states appear on the map, the more controversies concerning the health consequences of the non-medical weed use emerge. The experts and researchers from all over the world are painstakingly piecing together the limited available data on recreational marijuana effects on health. In its turn, the World Health Organization decided to summarize the evidence collected during the last twenty years of marijuana research and has recently published a large report titled “The health and social effects of non-medical cannabis use.” In this article, we will tell you about the link between long-term cannabis use and cardiovascular problems.
Heart and blood vessel diseases, also known as cardiovascular diseases (CVD), include coronary artery illnesses, heart attack, stroke, angina, venous thrombosis, and others.
Many of the diseases are related to atherosclerosis—a condition that occurs when a plaque builds up inside the arteries in the heart, brain, legs, arms, pelvis, and kidneys and blocks the blood flow through them.
A heart attack may occur when the blood flow that delivers oxygen to the heart tissue is severely reduced or cut off completely.
An ischaemic stroke is the most common type of the stroke. It happens when a vessel that supplies blood to the brain gets blocked, most often because of a blood clot. When the blood flow to a part of the brain is stopped, brain cells die and, as a result, a patient loses the ability to carry out some of the functions like talking or walking.
Tachycardia is one of the most reliable signs of marijuana intoxication: THC, the psychoactive component of cannabis, increases heart rate almost immediately after smoking by more than a hundred beats per minute (BPM). This condition usually lasts for the first couple of hours.
While some people can have no clear symptoms of tachycardia, others may feel dizziness, lightheartedness, shortness of breath, or chest pain.
The study on the role of the endocannabinoid system in cardiovascular function showed that “the CB1 and CB2 cannabinoid receptors are both found in the cardiovascular system.”
According to a 2002 scientific review by the University of California, tolerance to most of the initial CVD effects appears rapidly. For example, young daily marijuana users developed tolerance to the marijuana effects within 2-4 weeks. On the other hand, middle-aged male cannabis smokers who previously experienced myocardial infarction can feel acute symptoms of angina. Back in 1974, cannabis has been found to trigger angina symptoms after physical efforts in patients that previously experienced coronary diseases or stable angina.
The scientists point out that only a small number of epidemiological studies of cardiovascular diseases show a link between marijuana use and CVD. According to some studies, cannabis use may increase the risk of cardiovascular mortality 2.5 times in those who use weed less than weekly and 4.2 times in those who use cannabis more often. The quality of the case reports is insufficient, and the available evidence of the risks of CVD in cannabis smokers is not consistent, although mortality rates were found to be “systematically higher” in pot lovers than in non-users.
Between 2006 and 2010, there were 35 cases of CVD in French marijuana users reported by the national Addictovilligance network. An average age of the patients was 34 years. On the basis of this result, all the cases “should be regarded as a considerable underestimate of the number of cardiovascular diseases that could have occurred among young cannabis users in France during the study period.” During the study period, the risks of CVD were found to increase up to three times.
Myocardial infarction (MI) is commonly known as heart attack. It occurs when blood flow to the heart stops, causing damage to the heart muscle. The patient often feels chest, shoulder, arm, back, jaw, or neck pain, weakness or coldness of arms and legs, numbness.
Smoking marijuana is known to have hemodynamic consequences (increased heart rate, supine hypertension, postural hypotension) and can potentially trigger the onset of myocardial infarction. There are concerns about the analgesic effects of THC that may mask pain, delaying treatment seeking. Marijuana smoking may also increase the levels of carboxyhemoglobin in the blood while decreasing oxygen delivery to the heart and increasing the risks of atheromas. The cardiovascular impairments observed in young cannabis smokers differ from those observed in non-users of the same age.
Marijuana is supposed to be linked with stroke. The latest research on cannabis that investigated the difference between cannabis users and non-users showed that ischemic strokes in youngsters who use the drug is more likely to result from intracranial arterial stenosis while the most common cause of stroke in non-users was cardioembolism.
In 2015, the researchers at the American Society of Clinical Oncology and the College of American Pathologists found “only 59 cases of cannabis-associated strokes in the literature. These were ischaemic attacks that occurred in persons with a mean age of 33 years.”
Marijuana-associated strokes may occur in heavy or current smokers who smoke tobacco as well. These strokes happen while smoking or a few minutes later. The cardiovascular effects of weed also affect the risk of the stroke—cannabis may cause orthostatic hypotension, swings in blood pressure, vasculopathy, and altered cerebral vasomotor function. All these conditions can lead to a stroke.
Still, according to the WHO report, the French studies that examined the connection between marijuana and cardiovascular disorders were insignificant and larger cohort and better-designed case-control studies are needed to draw conclusions.