GXT responses in altitude-acclimatized cyclists during sea-level simulation

Area of Science:

• Exercise Physiology
• Altitude Acclimatization
• Human Performance

Background:

• Athletes residing at moderate altitude (MA) experience physiological adaptations.
• Understanding exercise responses during sea-level (SL) simulation is crucial for performance optimization.

Purpose of the Study:

• To investigate the impact of gender on graded exercise stress test (GXT) responses in MA-acclimatized cyclists simulating SL conditions.
• To determine if arterial oxygen saturation (S(a)O2) changes correlate with VO2peak improvements.

Main Methods:

• Twenty competitive cyclists (12 males, 8 females) from MA locations performed randomized bicycle GXTs under simulated SL and local normoxic hypobaric conditions.
• Physiological parameters including VO2peak, S(a)O2, and lactate threshold (LT) were measured.

Main Results:

• Simulated SL conditions led to significant increases in VO2peak, improved economy at LT, and enhanced peak power in cyclists.
• Higher resting and peak S(a)O2 with less desaturation were observed at SL compared to MA.
• Individual variability in VO2peak improvement was substantial and not correlated with S(a)O2; correlations between performance metrics varied by gender.

Conclusions:

• Chronic MA residence may reduce exercise-induced hypoxemia and decouple S(a)O2 from VO2peak changes at SL.
• Aerobic performance improvements in MA residents at SL exhibit significant individual variability.
• The mechanisms driving performance enhancements may differ between male and female cyclists.