Marijuana and the heart

Marijuana has an immediate effect on the heart. Within minutes of smoking marijuana, heart rate increases by as much as 50 beats per minute.

This can increase even more if other drugs are used.

It causes blood vessels to relax and dilate which allows blood to flow more easily. This causes a drop in blood pressure.

What often happens is a small increase in blood pressure after consumption but this is followed by a fall in blood pressure, especially after large doses of marijuana.

Blood pressure drops when the user is standing and increases slightly when they are seated. This causes dizziness and the risk of fainting if they suddenly stand up.

This combination of increased heart rate (known as ‘tachycardia’) and lowered blood pressure increases the risk of a heart attack. This can be as much as 4 times the normal risk and occurs within the first hour after smoking marijuana.

The problem is that this increased heart rate forces the heart to work harder than normal which means that it pumps less efficiently and reduces blood follow around the body.

This also reduces essential oxygen to the heart which can lead to conditions such as ischemia and even a heart attack.

All of these effects are dangerous for anyone who has a cardiovascular condition or high blood pressure (hypertension).