Hematologic response to four weeks of intermittent hypobaric hypoxia in highly trained athletes.

We investigated changes induced by four weeks of intermittent hypobaric hypoxia (IHH) at a simulated altitude of 4000-5500 m in highly trained athletes. Serum erythropoietin increased significantly (p<0.001) after the sessions of IHH, but reticulocyte and red cell parameters did not. Our IHH protocol stimulated endogenous erythropoietin secretion without producing the subsequent erythropoietic response.