Changes in erythropoietin and vascular endothelial growth factor following the use of different altitude training concepts.

Abstract

Erythropoietin (EPO) and vascular endothelial growth factor (VEGF) are important factors regulating erythropoiesis and angiogenesis. Altitude/hypoxic training may induce elevated VEGF-A and EPO levels. However, it appears that the range of adaptive changes depends largely on the training method used. Therefore, we investigated the changes in EPO and VEGF-A levels in athletes using three different altitude/hypoxic training concepts. Thirty-four male cyclists were randomly divided into four groups: LH-TL group ("live high-train low" protocol), HiHiLo ("live high - base train high - interval train low" procedure), IHT ("intermittent hypoxic training") and control group (CN, normoxic training). The same 4-week training program was used in all groups. Blood samples were taken before and after each training week in order to evaluate serum EPO and VEGF-A levels. In the LH-TL and HiHiLo groups, EPO increased (P<0.001) after 1st week and remained elevated until 3rd week of altitude training. In the IHT and CN groups, EPO did not change significantly. VEGF-A was higher (P<0.001) after 2nd and 3rd week of training in the IHT group. In the HiHiLo group, VEGF-A changed (P<0.05) only after 3rd week. No significant changes of VEGF-A were noted in the LH-TL and CN groups. Altitude/hypoxic training is effective in increasing VEGF-A and EPO levels. However, a training method plays a key role in the pattern of adaptations. EPO level increase only when an adequate hypoxic dose is provided, whereas VEGF-A increases when the hypoxic exposure is combined with exercise, particularly at high intensity.