Detecting Performance-Enhancing Drugs

World records in sports are broken by better athletes, better training methods, better nutrition or new drugs. Drugs appear to be the cause of many recent records in sports requiring strength and speed. Many bicycle racers know that some drugs that make them better riders can’t be detected by testing techniques that are available today. A recent study shows that laboratories have no definitive test to discover athletes who take erythropoietin (EPO), a drug to boost their red blood cell counts (Haematologica, August, 2006). Athletes have found that taking very low doses of EPO daily will raise red blood cell counts, and will not give test results high enough to show that they are taking extra EPO.

The primary limiting factor to how fast a person can ride a bicycle over long distances is the time it takes to move oxygen from the lungs into the muscles. So anything that increases oxygen transport from the lungs into the bloodstream, or carries more oxygen in the bloodstream, or moves oxygen faster from the blood into muscles will make a person a faster bicycle racer. Since more than 95 percent of the oxygen in the bloodstream is carried by hemoglobin in red blood cells, anything that increases the concentration of red blood cells will help a racer ride faster.

When healthy people do not get enough oxygen, their kidneys produce a hormone called EPO that causes the bone marrow to make more red blood cells. When athletes are given additional EPO, their red blood cell counts rise and their performance improves.

Doctors can do blood tests for EPO, but the hormone lasts only a few days in the bloodstream, so athletes who stop taking EPO several days before testing may not be caught. Some athletes tried to foil the test by adding pepsin, a chemical found in spot removers, to their urine samples. However this destroyed all of the EPO including their own natural EPO, so they failed the test because a person is supposed to have some EPO. The new study shows that athletes have now found a way to circumvent the test by taking very low doses of EPO every day.

Carbohydrates Can Increase Endurance

A study from The University of Bern in Switzerland shows that a high carbohydrate, high-fat diet for three days before competition can help athletes store more fat in their muscles and use much more muscle fat for energy during exercise (European Journal of Applied Physiology, November, 2006). Endurance-trained athletes exercised for three hours to empty sugar and fat reserves from their muscles. Then they ate a high-carbohydrate, low-fat diet for 2.5 days or the same diet with lots of added fat for the last 1.5 days. Athletes who ate the high-carbohydrate, high-fat diet stored 55 percent more fat in their muscles and used more than three times as much of that fat during exercise.

The data on fat storage may have no practical value for endurance athletes because the authors were not able to show that the extra fat stored in muscles increased endurance. This is probably because there is almost an unlimited amount of energy available from a person’s own body fat. Changing the percentage of fat use from body fat to muscle fat would not increase energy sources and therefore would not increase endurance.

Carbohydrates are another story. Normally there is only a small amount of carbohydrates stored in the muscles, liver and bloodstream. Storing extra carbohydrates in muscles is beneficial because when a person runs out of stored muscle sugar, his muscles hurt and are more difficult to control. In the 1940s, Per Olaf Ostrand showed that a high carbohydrate diet for several days before athletic competitions helps a person store more sugar in muscles, which does increase endurance. Since then athletes have eaten high-carbohydrate diets before competition and often have pre-race pasta parties. Subsequent studies showed that highly-conditioned endurance-trained athletes can maximally fill their muscles with sugar just by eating their usual meals and cutting back on their heavy workloads for a few days before competition.