Hematology (Polycythemia Vera)

Anabolic-androgenic steroids stimulate the production of red blood cells. However, a potential adverse effect is polycythemia or excessive red blood cell production. Polycythemia is reflected in hematocrit levels, which are the percentage of blood volume composed of red blood cells. As hematocrit levels rise, so does the viscosity of the blood. If the blood becomes too thick, its ability to circulate is compromised. This significantly increases the risk of serious thrombotic events, including embolism and stroke. High hematocrit levels are also a risk factor for heart disease. The normal hematocrit range for men is 40.7% to 50.3%, and for women, it is 36.1% to 44.3% (values may vary slightly depending on the source). A hematocrit level of 50% is considered normal, while levels above 60% are deemed dangerous and potentially life-threatening.

Anabolic steroid administration often raises hematocrit levels by several percentage points, sometimes even more. Therefore, many bodybuilders who use steroids have hematocrit levels above the normal range. For example, one study measured the average hematocrit of a group of bodybuilders abusing steroid hormones at 55.7%. Clinically, this level is considered high, increasing blood viscosity and the risk of severe cardiovascular events. While it is unlikely to be the sole cause, high hematocrit is believed to be a contributing factor in the deaths of many steroid abusers, often in conjunction with hypertension, high homocysteine, and/or atherosclerosis. In contrast, the average hematocrit level for bodybuilders not taking anabolic-androgenic steroids is 45.6%, which is well within the normal range for healthy adult males.

Many doctors specializing in hormone replacement therapy consider a hematocrit level of 55% to be an absolute threshold. Above this level, anabolic-androgenic steroid therapy cannot be safely continued. At this point, drug intake should cease until the hematocrit issue is corrected. Mild elevations in hematocrit can be addressed with phlebotomy. During steroid intake, removing one pint of blood periodically, usually every two months, can help manage hematocrit levels. Proper hydration is also crucial, as dehydration can temporarily elevate hematocrit levels, resulting in a false positive for polycythemia. If hematocrit levels exceed normal values, aspirin intake is often recommended as it reduces platelet aggregation, or the tendency for platelets to stick together and form clots. Individuals must remain vigilant about the potential cardiovascular risks associated with high hematocrit levels related to anabolic-androgenic steroid use.