MUCH INDIVIDUAL AND GENDER VARIATION IN MODERATE-ALTITUDE RESIDENTS WHEN EXPOSED TO SEA-LEVEL
Brothers, M. D., Hilger, K., Carson, J. M., Sullivan, L., & Byrnes, W. C. (2007). GXT responses in altitude acclimatized cyclists during sea level simulation. ACSM Annual Meeting New Orleans, Presentation Number, 922.
This study examined the changes in physiological parameters that predict performance in cyclists acclimatized to moderate altitude and acutely exposed to sea-level simulation. Competitive cyclists (M = 12; F = 8) who were moderate-altitude residents underwent two randomized bicycle graded exercise stress tests (GXT) - one under local normoxic hypobaria (moderate altitude) and the other under simulated sea-level conditions. P>
Under the sea-level condition, the cyclists demonstrated a significant increase (2 to 3%) in absolute and relative VO2peak, improved (4%) economy at lactate threshold, and time-adjusted peak power (7%). Improvements varied between individuals ranging from -6% to +25%. Simulated sea-level also resulted in a greater arterial saturation at rest and VO2peak, and significantly less desaturation from rest to VO2peak. The genders differed in their responses.
Implication. Moderate-altitude residents improve in performance and have altered physiological responses upon performing in sea-level conditions. However, the individual variations and gender differences warrant individual monitoring of response capabilities before assuming the nature of any adaptation.
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