A form of performance enhancing practice that does not include chemicals is called blood doping. Oxygenated blood is drawn from an athlete's body several weeks prior to competition. The night before a race or match the blood is reintroduced into the body allowing greater feats of muscular performance from the increased red blood cells and added oxygenation. This practice can cause very dangerous levels of blood hemoglobin to collect in the bloodstream. It can cause heart attacks and strokes. There have been several cyclists have died from this practice. There are risks associated with the transfusion of blood or blood substances including allergic reactions, kidney damage, fever, jaundice, the transmission of infectious diseases like hepatitis and AIDS, and overloading the circulatory system causing metabolic shock.

Detecting Drugs
Testing for illegal substances has been used to fight doping, but athletes have been trying to hide or mask their use from officials. Testing for illegal substances has improved and now labs can detect a wide range of drugs or other stimulants. There is now a test that can even determine if the body has high hemoglobin levels caused by blood doping.

There is still no test available that can detect growth hormones. Some over the counter drugs, including cold medications, may contain stimulants that in large enough quantities act like amphetamines and will show up on a drug screening. Several well-known athletes have sued after wrongly be accused of drug use.

Summary
It is unfortunate that athletes feel they have to risk their lives and practice doping for that small added edge. It is not surprising. Top athletes are adored, compensated greatly, and made role models. As the rewards of athletic glory are so high, there will be those willing to risk everything to gain them. To gain a more competitive edge, nothing works better than proper training, proper rest, good nutrition, correct technique, and good coaching.