REDUCED PERFORMANCE OF MALE AND FEMALE ATHLETES AT 580 M ALTITUDE

This study examined the effect of mild hypobaria (MH) on the peak oxyg en consumption (VO2peak) and performance of ten trained male athletes [(x) over bar (SEM); VO2peak = 72.4 (2.2) ml . kg(-1). min(-1)] and te n trained female athletes [VO2peak = 60.8 (2.1) ml . kg(-1). min(-1)]. Subjects performed 5-min maximal work tests on a cycle ergometer with in a hypobaric chamber at both normobaria (N, 99.33 kPa) and at MH (92 .66 kPa), using a counter-balanced design. MH was equivalent to 580 m altitude. VO2peak at MH decreased significantly compared with N in bot h men [-5.9 (0.9)%] and women [-3.7 (1.0)%]. Performance (total kJ) at MH was also reduced significantly in men [-3.6 (0.8)%] and women [-3. 8 (1.2)%]. Arterial oxyhaemoglobin saturation (SaO2) at VO2peak was si gnificantly lower at MH compared with N in both men [90.1 (0.6)% versu s 92.0 (0.6)%] and women [89.7 (3.1)% versus 92.1 (3.0)%]. While SaO2 at VO2peak was not different between men and women, it was concluded t hat relative, rather than absolute, VO2peak may be a more appropriate predictor of exercise-induced hypoxaemia. For men and women, it was ca lculated that 67-76% of the decrease in VO2peak could be accounted for by a decrease in O-2 delivery, which indicates that reduced O-2 tensi on at mild altitude (580 m) leads to impairment of exercise performanc e in a maximal work bout lasting approximate to 5 min.