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Normoxic and acute hypoxic exercise tolerance in man following acetazolamide
J M Stager1, A Tucker, L Cordain
1Department of Kinesiology, Indiana University, Bloomington 47405.
Medicine and Science in Sports and Exercise
|April 1, 1990
Summary
Acetazolamide (ACZ) impairs exercise performance by reducing time to exhaustion, despite no significant changes in oxygen consumption. This drug affects blood and urine pH, impacting endurance in both normal and hypoxic conditions.
Area of Science:
- Exercise Physiology
- Pharmacology
Background:
- Acetazolamide (ACZ) is a carbonic anhydrase inhibitor.
- Its effects on exercise performance under normoxic and hypoxic conditions require further elucidation.
Purpose of the Study:
- To investigate the influence of acetazolamide (ACZ) on maximal and submaximal exercise performance.
- To assess ACZ's impact under both normoxic and hypoxic conditions.
Main Methods:
- Quasi-randomized, double-blind, crossover study with 27 healthy male subjects.
- Administration of 500 mg ACZ or placebo (Pla) prior to exercise.
- Measurements included VO2, VCO2, RER, HR, VE, pH, bicarbonate, and lactate levels at rest and during exercise.
Main Results:
- ACZ lowered venous pH and bicarbonate, and elevated urine pH at rest.
- In normoxia, peak VO2 was unaffected, but peak VCO2 and RER decreased.
- Submaximal exercise showed increased VE (14%) and reduced time to exhaustion (29%) with ACZ.
- Hypoxic conditions revealed higher PCO2 and lower venous lactate with ACZ at peak VO2.
Conclusions:
- Acetazolamide (ACZ) negatively impacts exercise performance, particularly time to exhaustion.
- ACZ alters acid-base balance, affecting physiological responses during exercise.
- Further research is needed to understand ACZ's role in exercise under varying environmental conditions.