Final answer:
Athletes abuse erythropoietin (EPO) to increase oxygen delivery to muscles, but this practice is potentially dangerous due to its effects on blood viscosity and cardiovascular health.
Step-by-step explanation:
Erythropoietin (EPO) is a hormone that stimulates the production of red blood cells in the bone marrow. Some athletes abuse synthetic EPO to increase their red blood cell count and improve oxygen delivery to their muscles, which enhances endurance.
However, this abuse is potentially dangerous because it can raise blood viscosity, making it difficult for blood to circulate effectively within the body. In extreme cases, this can lead to heart strain and even death. EPO abuse also increases the risk of blood clots, heart attacks, and strokes.
To summarize, athletes hope to derive the potential benefit of increased oxygen delivery to tissues by abusing EPO, but this practice is risky due to its effects on blood viscosity and cardiovascular health.