In addition to being controlled substances, narcotics have significant negative physical effects on the body. People under the influence of marijuana perform poorly in virtually every sort of mental and physical task, especially athletics. The increase in heart rate after smoking pot decreases the body's maximum tolerance for exercise, makes the smoker more vulnerable to fatigue, and makes breathing more difficult. It also causes slower reflexes, a distorted sense of time, poor vision, and an interference with depth perception. Cocaine has powerful stimulant effects. Like caffeine, it greatly increases heart rate and blood pressure. It also blocks the body's ability to eliminate adrenaline. The reason most people use it is the euphoric feeling that occurs shortly after use. However, cocaine's effects on strength and endurance aren't documented. People who use cocaine feel competent and aggressive, but there's no evidence they perform any better than they would without the drug. Cocaine is highly addictive and can cause heart seizures. Ergogenic (ur-guh-JEN-ick), or performance-enhancing drugs, are used by athletes primarily to help them perform faster, stronger, and longer. These include amphetamines and steroids. Other narcotics are sometimes improperly used by athletes to speed recovery time, heal injuries, reduce pain, lessen anxiety, and lose weight. These include painkillers, anti-inflammatory drugs, narcotic analgesics (an-uhl-JEE-zicks), tranquilizers, human growth hormones, beta-blockers, and diuretics (dye-yur-REH-tiks). Without proper medical attention, all these can have significant risks to immediate health, as well as cause long-term problems.