ALTITUDE EXPOSURE STIMULATES INCREASED EPO IN DISTANCE RUNNERS; NO GENDER DIFFERENCES
Chapman, R. F., Derchak, P. A., Stager, J. M., Stray-Gundersen, J., & Levine, B. D. (2008). Erythropoietin production at moderate altitude in elite endurance athletes is not mediated by peripheral chemoresponsiveness. ACSM 55th Annual Meeting Indianapolis, Presentation Number, 1267.
"The level of erythropoietin (EPO) release by the kidney has been directly related to the severity of hypoxic stress. However, the acute EPO response to a fixed altitude shows substantial variability between subjects. Arterial PO2 with acute altitude exposure is regulated in part by the hypoxic ventilatory response (HVR), which also shows a wide inter-subject variability." This study investigated if the ventilatory response to hypoxia influences the magnitude of EPO release with acute exposure to moderate altitude. National class U.S. distance runners (M = 17; F = 9) participated in a test of isocapnic hypoxic ventilatory response at sea level 2-7 days before departing to an altitude training camp. Plasma EPO concentrations were determined by radio-immuno assay on samples collected at sea level and after 20 hours of residence at 2,500 m.
No significant difference was observed for the hypoxic ventilatory response between the male and female athletes. EPO was significantly increased from pre-altitude (8.6 + 2.6 IU/mL, range 4.0 to 14.6 IU/mL) to acute altitude (16.6 + 4.4 IU/mL, range 5.0 to 27.0 IU/mL). There was no significant gender difference in the magnitude of the EPO increase, despite the women having lower baseline hemoglobin levels and O2 carrying capacity. The acute increase in EPO with altitude exposure for all Ss was not correlated with HVR and no correlation was present between DEPO and HVR within the group of men or women.
Implication. The variability in the acute EPO response to moderate altitude was not explained by differences in peripheral chemoresponsiveness in elite distance runners. It was suggested that factors acting downstream from the lung influence the magnitude of the acute EPO response to altitude in distance runners.
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