Document Detail

Effect of acetazolamide on leg endurance exercise at sea level and simulated altitude.
MedLine Citation:
PMID:  16499476     Owner:  NLM     Status:  MEDLINE    
Acetazolamide can be taken at sea level to prevent acute mountain sickness during subsequent altitude exposure. Acetazolamide causes metabolic acidosis at sea level and altitude, and increases SaO2 (arterial oxygen saturation) at altitude. The aim of the present study was to determine whether acetazolamide impairs muscle endurance at sea level but not simulated altitude (4300 m for <3 h). Six subjects (20+/-1 years of age; mean+/-S.E.M.) performed exhaustive constant work rate one-leg knee-extension exercise (25+/-2 W) once a week for 4 weeks, twice at sea level and twice at altitude. Each week, subjects took either acetazolamide (250 mg) or placebo orally in a double-blind fashion (three times a day) for 2 days. On day 2, all exercise bouts began approx. 2.5 h after the last dose of acetazolamide or placebo. Acetazolamide caused similar acidosis (pH) in all subjects at sea level (7.43+/-0.01 with placebo compared with 7.34+/-0.01 with acetazolamide; P<0.05) and altitude (7.48+/-0.03 with placebo compared with 7.37+/-0.01 with acetazolamide; P<0.05). However, endurance performance was impaired with acetazolamide only at sea level (48+/-4 min with placebo compared with 36+/-5 min with acetazolamide; P<0.05), but not altitude (17+/-2 min with placebo compared with 20+/-3 min with acetazolamide; P = not significant). In conclusion, lack of impairment of endurance performance by acetazolamide compared with placebo at altitude was probably due to off-setting secondary effects resulting from acidosis, e.g. ventilatory induced increase in SaO2 for acetazolamide compared with placebo (89+/-1 compared with 86+/-1% respectively; P<0.05), which resulted in an increased oxygen pressure gradient from capillary to exercising muscle.
Charles S Fulco; Steven R Muza; Dan Ditzler; Eric Lammi; Steven F Lewis; Allen Cymerman
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  Clinical science (London, England : 1979)     Volume:  110     ISSN:  0143-5221     ISO Abbreviation:  Clin. Sci.     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-05-12     Completed Date:  2006-08-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7905731     Medline TA:  Clin Sci (Lond)     Country:  England    
Other Details:
Languages:  eng     Pagination:  683-92     Citation Subset:  IM    
Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine (USARIEM), Kansas Street, Natick, MA 01760-5007, USA.
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MeSH Terms
Acetazolamide / administration & dosage*
Analysis of Variance
Carbonic Anhydrase Inhibitors / administration & dosage*
Double-Blind Method
Muscle, Skeletal / physiology*
Oxygen / blood
Physical Endurance*
Reg. No./Substance:
0/Carbonic Anhydrase Inhibitors; 59-66-5/Acetazolamide; 7782-44-7/Oxygen

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