Effect of Acetazolamide on Isolated Quadriceps Muscle Endurance Performance at Sea Level and During Acute Altitude Exposure.

摘要

Acetazolarnide (AZ) can be taken at sea level (SL) to prevent acute mountain sickness during subsequent altitude (ALT) exposure. AZ causes metabolic acidosis at SL and ALT, and increases arterial oxygen saturation (SaO2) at ALT. HYPOTHESIS: AZ will impair muscle endurance at SL but not ALT (4300 m, <3 h). METHODS: Six subjects (2012 yr; Xl SD) performed exhaustive constant work rate 1-leg knee extension exercise (2512 watts) once per wk for 4 wks (2 wks at SL and 2 wks at ALT). Each week, subjects took either AZ (250 mg) or placebo orally (double blind) every 8 h starting one-day prior to exercise. All exercise bouts began 3 h after the last (i.e., 4th) dose and 2 bouts began 2 h after ALT exposure. RESULTS: AZ caused similar acidosis in the same subjects at SL and ALT, but muscle endurance was impaired only at SL. CONCLUSION: Lack of endurance impairment at ALT during AZ was likely due to offsetting secondary effects resulting from the acidosis (e.g., increased SaO2) that improved muscle oxygen delivery.