title: Exercise limitation of acetazolamide at altitude (3459 m).
abstract: OBJECTIVE
  To assess the effect of acetazolamide (Az) on exercise performance during early acclimatization to altitude.
  
  
  METHODS
  Az (250 mg twice daily) or placebo was administered for 3 days in a double-blind, randomized manner followed by a rapid ascent to 3459 m in the Italian Alps. Twenty healthy adults (age range, 18-67 years) were tested at 60% of sea-level peak power output for 15 minutes on a bicycle ergometer after 16 to 27 hours of altitude exposure. Exercise performance was measured in relation to peripheral oxygen saturations measured from pulse oximetry (Spo2), Lake Louise acute mountain sickness (AMS) score, and perceived difficulty.
  
  
  RESULTS
  At altitude, resting Spo2 was higher in the Az group compared with placebo (P < .001). The highest AMS scores were in 4 of the placebo individuals with the lowest resting Spo2 (P < .05). During the exercise test, Spo2 fell in all but 1 subject (P < .001) and was reduced more in the Az group (P < .01). Four Az and 1 placebo subject were unable to complete the exercise test; 4 of these 5 had the largest fall in Spo2. The perception of exercise difficulty was higher in the Az subjects compared with those taking the placebo (P < .01). There was an age relationship with exercise limitation; 4 of the 9 older than 50 years failed to complete the test whereas only 1 of 11 younger than 50 years failed, and there were no failures in the 6 younger than 30 years (P < .05).
  
  
  CONCLUSIONS
  In this study group, and despite higher resting Spo2, Az may have compromised exercise at 3459 m altitude during early acclimatization, particularly in older subjects.
authors.affiliation: School of Medicine, University of Birmingham, Birmingham (Drs Bradwell and Wright). Electronic address: a.r.bradwell@bham.ac.uk.
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Bradwell
authors.affiliation: Department of Sport & Exercise Sciences, University of Chichester, Chichester (Dr Myers and Ms Ashdown).
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Myers
authors.affiliation: Spencer Street Surgery, Carlisle (Dr Beazley).
authors.forename: Maggie
authors.initials: M
authors.lastname: Beazley
authors.affiliation: Department of Sport & Exercise Sciences, University of Chichester, Chichester (Dr Myers and Ms Ashdown).
authors.forename: Kimberly
authors.initials: K
authors.lastname: Ashdown
authors.affiliation: Merrist Wood College Worplesdon Guildford (Mr Harris).
authors.forename: Nick G
authors.initials: NG
authors.lastname: Harris
authors.affiliation: University College London, London (Ms Bradwell).
authors.forename: Susie B
authors.initials: SB
authors.lastname: Bradwell
authors.affiliation: The University of Warwick, Coventry (Mr Goodhart and Dr Imray).
authors.forename: Jamie
authors.initials: J
authors.lastname: Goodhart
authors.affiliation: The University of Warwick, Coventry (Mr Goodhart and Dr Imray); University Hospital Coventry and Warwickshire NHS Trust, Coventry (Drs Imray and Wimalasena).
authors.forename: Chris H
authors.initials: CH
authors.lastname: Imray
authors.affiliation: University Hospital Coventry and Warwickshire NHS Trust, Coventry (Drs Imray and Wimalasena).
authors.forename: Yashvi
authors.initials: Y
authors.lastname: Wimalasena
authors.affiliation: St George's Healthcare NHS Trust, London (Dr Edsell).
authors.forename: Mark E
authors.initials: ME
authors.lastname: Edsell
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford (Dr Pattinson).
authors.forename: Kyle T S
authors.initials: KT
authors.lastname: Pattinson
authors.affiliation: School of Medicine, University of Birmingham, Birmingham (Drs Bradwell and Wright).
authors.forename: Alex D
authors.initials: AD
authors.lastname: Wright
authors.affiliation: QinetiQ, Farnborough (Mr Harris), United Kingdom.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Harris
mesh_terms: D000064:Acclimatization; D000086:Acetazolamide / Q000627:therapeutic use*; D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000531:Altitude; D000532:Altitude Sickness / Q000188:drug therapy*; D002257:Carbonic Anhydrase Inhibitors / Q000627:therapeutic use*; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D055815:Young Adult
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide
keywords: acetazolamide; altitude; exercise