According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death for both men and women in the US. More than half of the deaths due to heart disease in 2015 were in men and about 630,000 Americans die from heart disease each year—that’s 1 in every 4 deaths.
Cannabis consumers are often warned about the damage the drug does to their brain, but what about their heart?
A Look into the Cardiovascular System
First off, the cardiovascular system (CVS), also known as the circulatory system or the vascular system, is an organ system that permits blood to circulate and transport nutrients such as amino acids, electrolytes, oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH acid-base content, and maintain homeostasis.
When this system fails in any way, it could lead to a myocardial infarction (MI), also known as a heart attack, where part of the heart muscle dies or can even lead to a stroke. Some cardiovascular risk factors include high cholesterol levels, obesity rates, and diabetes.
Another important risk factor is increased heart rate (HR), which is the speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body’s physical needs, including the need to absorb oxygen and excrete carbon dioxide.
HR can increase after the consumption of high dose THC in some patients who are vulnerable to high resting HR, to begin with. One study found that risk of heart attack increases five times within one hour of consuming cannabis.
Can cannabis therapy increase heart rate?
The activation of endocannabinoid receptor CB1 by THC can increase heart rate by 20-50bpm. This increase happens to compensate for the reduction in blood pressure caused by THC through blood vessel dilation, which makes the heart work faster.
CB1 also increases the risk of atherosclerosis, where the lining of the blood vessels gets blocked by plaque, increasing the risk of heart damage.
Though CB1 receptors seem to negatively impact the heart, the opposite can be said of CB2 receptors which may actually reverse the effects of CB1 receptors on the heart. They can be a promising target to lessen the damage caused by injury or cardiovascular attack.
However, having said all this about high THC doses, studies do suggest that low doses of THC may reduce plaque buildup and risk for atherosclerosis. This beneficial low-dose effect is thought to come from THC’s activation of CB2 receptors and not CB1 receptors.