Sports haematology

While the crucial role of haemoglobin in aerobic exercise has been well acc epted, there is still a great deal of controversy about the optimal haemato logical parameters in the athletic population. The initial part of this rev iew will examine the question of anaemia in athletes. The most common findi ng in athletes is a dilutional pseudoanaemia that is caused by a plasma vol ume expansion, rather than an actual blood loss. It is not a pathological s tate and normalises with training cessation in 3 to 5 days. This entity sho uld be distinguished from conditions associated with lowered blood counts, such as intravascular haemolysis or iron deficiency anaemia. The evaluation of true anaemia states in the athlete must take into account not only bloo d losses secondary to exercise, such as foot strike haemolysis or iron loss es through sweat, but non-athletic causes as well. Depending on the age and sex of the athlete, consideration must be given to evaluation of the gastr ointestinal or genitourinary systems for blood loss. Finally, a comprehensi ve nutritional history must be taken, as athletes, especially women, are fr equently not consuming adequate dietary iron. The second section of the paper will deal with the very contentious issue o f sickle cell trait. While there have been studies demonstrating an increas ed risk of sudden death in people with sickle cell trait, it is still quite rare and should not be used as a restriction to activity. Further, studies have demonstrated that patients with sickle cell trait have an exercise ca pacity that is probably normal or near normal. However, in the cases of sud den death, it has been secondary to rhabdomyolysis occurring among sickle c ell trait athletes performing at intense exertion under hot conditions, soo n after arriving at altitude. The recommendations are that athletes with si ckle cell trait adhere to compliance with the general guidelines for fluid replacement and acclimatisation to hot conditions and altitude. The final section of the paper examines the issue of haematological manipul ation for the purposes of ergogenic improvement. Although experiments with blood doping revealed improvements in running time to exhaustion and maxima l oxygen uptake. the introduction of recombinant erythropoietin has rendere d blood doping little more than a historical footnote. However, the improve ments in performance are not without risk, and the use of exogenous erythro poietin has the potential for increased viscosity of the blood and thrombos is with potentially fatal results. Until a definitive test is developed for detection of exogenous erythropoietin, it will continue to be a part of el ite athletics.