the first-line treatment for post-transplant erythrocytosis specificity is angiotensin-converting enzyme (ace) inhibitors or angiotensin receptor blockers. relation to athletic performance polycythemia is theorized to increased performance in endurance sports due to the blood being able to store more oxygen. this idea has led to the illegal use of blood doping and transfusions among professional athletes, as well as use of altitude training or elevation training masks to simulate a low-oxygen environment. however, the benefits of altitude training for athletes to improve sea-level performance are not universally accepted, with one reason being athletes at altitude might exert less power during training.