According to the National Institute on Drug Abuse (NIDA), marijuana or "weed" is the most commonly abused illicit drug in the United States. It is often dried and shredded and commonly smoked. The chemical that produces the intoxicating effects is tetrahydrocannabinol, often called THC for short. The THC in weed causes multiple detrimental effects on a man's health.
Brain
After a person smokes weed, THC quickly travels through the bloodstream to the brain. Thus, the most noticeable and near-immediate effect of smoking weed is the "high" that it produces. According to NIDA, this effect is due to certain molecules in the brain called cannabinoid receptors that bind THC, triggering activity in the part of the brain that produces feelings of pleasure. Other parts of the brain have cannabinoid receptors as well, including those that control memory, learning, perception of time and coordination. When a man smokes weed, he is therefore less effectively able to learn, perform complex tasks or have a normal sense of the passage of time.
Lungs
Smoking weed can cause intense coughing and a burning sensation in the lungs. A man who regularly smokes weed has an increased risk of lung infections, similar to lung problems in smokers of tobacco, according to the Utah Department of Human Services. Additionally, smoking weed increases a person's risk of developing lung cancer.
Sex and Fertility
Smoking weed lowers a man's testosterone levels, states the Virtual Health and Wellness Center of Adelphi University. The National Institute on Aging notes that testosterone is a sex hormone that is much more elevated in men than in women and helps the testes develop. Testes are the male reproductive glands that make sperm. The effect on testosterone caused by smoking weed ultimately inhibits the making of sperm and can be the cause of a low sperm count. In addition to its effects on testosterone, smoking weed lowers sexual pleasure and can interfere with sexual performance.
Heart
Smoking weed increases a man's heart rate by 20 to 100 percent, according to NIDA. This effect generally lasts up to three hours after smoking and increases a man's risk of suffering a heart attack by almost fivefold. Smoking weed may also cause arrhythmia, which is an irregular heartbeat. Additionally, palpitations can occur, which are fast, "pounding" heartbeats.
