TRAINING STATUS DOES NOT INFLUENCE PHYSIOLOGICAL RESPONSES TO SIMULATED ALTITUDE
Puype, J., & Hespel, P. (2014). Predicting the effects of acute normobaric hypoxia on exercise performance from physiological measurements at rest. Medicine & Science in Sports & Exercise, 46(5), Supplement abstract number 1566.
“Altitude has been shown to affect aerobic exercise performance because of a hypoxia induced drop in oxidative energy input. However predictive analyses on the extent of aerobic performance decrement at different altitude levels based on resting physiological measurements are still scarce.”
This study examined the effects of acute exposure to normobaric hypoxia, in moderately- and well-trained athletes, on aerobic and anaerobic performance and to relate these changes to physiological measurements at rest. Males were assigned to either a well-trained (N = 8) and moderately-trained (N = 8) group. Ss underwent exercise testing at sea-level and at 1,200, 1,800, 2,400, and 3,000m simulated altitude. Altitudes were administered in random order and were separated by a 48 hours of recovery. The testing protocol comprised three consecutive phases: 1) Rest: 30 minutes in normoxia followed by 30 minutes in hypoxia, 2) VO2max test, 3) 30-second isokinetic Wingate test on a cycle ergometer.
There were no differences in resting heart rate, blood pressure, or pulmonary ventilation between the groups for any altitude. Resting arterial oxygen saturation decreased from 99.6±0.14% at 0m to 92.8±0.45% at 3000m in both groups. The gradual decline in VO2max (~21%) and drop in arterial oxygen saturation at VO2max (~15%) from sea-level to 3,000 m was similar for both groups. Mean power outputs during the Wingate test at sea-level were higher in well-trained group compared to the moderately-trained group while peak blood lactate concentrations were similar with no effect of altitude. Regression analysis showed that changes in resting arterial oxygen saturation were related to changes in arterial oxygen saturation at VO2max (r = 0.81) and VO2max (r = 0.73).
Implication. In a population of trained males, training status affects neither relative aerobic performance decrements nor anaerobic capacity between 0 and 3,000 m altitude. Only resting arterial oxygen saturation yielded adequate prediction of performance decrement at altitude.
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