Racing Heart
The National Institute on Drug Abuse reports that a few minutes after inhaling marijuana smoke a person's heart starts beating more rapidly. The heart rate goes from the normal 70 to 80 beats per minute to 90 to 130 beats per minute or more, which may significantly raise blood pressure. It could be a danger to the heart because raising the heart rate and blood pressure can reduce oxygen in the blood. Research into the effects of marijuana on the heart is limited, because many studies have focused on psychiatric, memory and learning difficulties in relation to the drug.
Chronic Use
A study found that chronic marijuana users might increase their risk of heart attack and stroke, according to the May 2008 issue of Molecular Psychiatry. Chronic use was described as smoking marijuana nearly every day. Heavy marijuana users had much higher levels of a protein in the blood that is known to increase triglycerides when compared with non-users. Triglycerides are fatty substances believed to cause coronary heart disease when they reach high levels in the blood.
Chemical Cause
The chemical that may cause the problem in chronic marijuana users is THC, the active ingredient that causes the pleasurable effects of the drug. THC binds to cannabinoid receptors on several cells in various organs in the body, the study under the National Institutes of Health (NIH) suggests. The organs affected include the brain, heart, liver, kidney and spleen. Researchers analyzed 18 long-term heavy marijuana users and 24 non-users. Marijuana has long been suspected of having effects on the heart, according to Dr. Jean Lud Cadet, a molecular neuropsychiatrist at the NIH and lead author of the study.
Before Attack
Many researchers cite a study done in 2000 and published in Circulation, the journal of the American Heart Association in 2001. The study looked at 3,882 people who survived heart attacks around the country. Of the 124 people who reported using marijuana regularly, 37 said they smoked it within 24 hours of having a heart attack and nine smoked it within an hour of the attack. The researchers concluded that the danger of having a heart attack jumps to 4.8 times within an hour after smoking marijuana. But it drops to 1.7 times in the second hour. The heart rate may increase about 40 beats a minute causing blood pressure to increase, and then abruptly fall when a person stands up. This could lead to a heart attack, according to Murray Mittleman, a researcher in the study and an assistant professor at Harvard Medical School and Harvard School of Public Health.
