What is the best reason for aerobic endurance athletes to avoid erythropoietin use?

• A. Hematocrit and hemoglobin levels may decrease
• B. May cause unregulated increase in RBC production
• C. Resistance to infectious disease may be impaired
• D. May reduce ability of blood to carry oxygen

Answer: (B)

Erythropoietin stimulates the bone marrow to produce more red blood cells. When used, this production can overshoot because dosing isn’t tightly controlled, leading to an unregulated rise in red blood cell mass. The result is higher hematocrit and thicker, more viscous blood. That makes the heart work harder to pump blood and greatly increases the risk of dangerous blood clots, stroke, or heart attack. This safety risk is the strongest reason to avoid EPO use for endurance athletes, even though more red cells could enhance oxygen delivery in theory. The other options don’t fit: EPO would not decrease hematocrit or hemoglobin, and its primary risk isn’t impaired infectious resistance.