Cardiovascular system

The cardiovascular system is the heart and the network of arteries, veins and capillaries that circulate blood, delivering oxygen and nutrients and removing waste.

The heart pumps blood through two loops, one to the lungs and one to the rest of the body, and blood pressure is the force that flow exerts on artery walls. Cardiovascular health is judged by blood pressure, resting heart rate, cholesterol and blood sugar levels, body weight, physical fitness and smoking status, and by measures of vessel stiffness and heart rhythm. Heart rate variability, the beat-to-beat variation in timing, reflects the balance of the autonomic nervous system and is used in research as a marker of stress and recovery.

Cardiovascular disease, including high blood pressure, coronary artery disease, heart failure and stroke, is the leading cause of death worldwide, and it is assessed through examination, blood tests, electrocardiography and imaging. Cannabinoid receptors are present in heart and vessel tissue; THC raises heart rate acutely, and CBD has been studied for effects on blood pressure and vessel function in small early trials with no established conclusions.