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METABOLIC AGENTS
 
ERYTHROPOIETIN (EPO )
 

It has been known for many years that blood loss and subsequent reinfusion of red blood cells (rbc) increases aerobic capacity and thus endurance performance levels. This practice became known as blood doping. The added blood volume increases the blood's oxygen carrying capacity thus increasing the quantity of oxygen to the working muscles.

The production of rbc is controlled by the hormone erythropoietin (EPO). Athletes soon realised that the synthetic production and intake of EPO could replace the banned and tedious practice of blood doping. The 1998 Tour de France saw the expulsion of several riders whose team was found to be in possession of EPO as well as other banned substances. Most studies on the benefits of EPO have concentrated on it's usage in anaemic patients where aerobic performance levels were shown to be improved as well as muscular endurance and strength. Surprisingly, little research exists on the effects on elite athletes although one study did show an increase in the aerobic capacity of athletes.

Possible problems that may occur from taking EPO include increased blood viscosity and blood pressure which may in turn lead to the risk of stroke, heart attack and heart failure. EPO is banned from athletic competition and new improved methods of detection are constantly being introduced.

 
ANTILIPEMIC AGENTS
 

Heart disease is unfortunately a major health problem in many countries. Hyperlipidimeia (an increase in blood lipids - cholesterol) is an important factor in cardiovascular disease. Antilipemic Agents (AA) are used in the treatment of cardiovascular problems. The relationship between AA and exercise performance has yet to be completely elucidated and it is more important to study their usage in the context of those undergoing treatment for cardiovascular disease than for athletes wishing to gain a sporting advantage. It is important for example, to look at the effects of patients exercising whilst taking AA drugs. AA may be linked to increased post-exercise muscle soreness and may reduce fat oxidation resulting in less energy being available. They are generally not classed as banned substances.

 
NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) & SALICYLATES
 

Anti-inflammatory drugs are often used to treat muscle and joint problems (sprains, tendinitis...), a popular example being Ibuprofen. Aspirin is the most widely used of the salicylate drugs. These drugs maybe useful in reducing muscle soreness especially after eccentric exercise such as plyometrics. NSAIDs may improve aerobic capacity through helping generate adenosine although little research has been carried out in this particular area and scientists are generally sceptical about any improvements in physical performance.

These drugs have been shown to cause gastrointestinal bleeding and ulcers. They can also lead to nephrotoxicity and acute renal failure. It is especially advisable for those involved in endurance sports not to overuse these drugs. They can be bought over the counter but their potential toxicity should not be underestimated and prolonged usage is not advised. Neither NSAIDS nor salicylates are banned in athletic competition.

Please note that Nutritional supplements such as Creatine, Chromium, Iron... which are also classed as Metabolic Agents will be looked at in the Nutrition section of the site.

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