Exercise limitation of acetazolamide at altitude (3459 m).
Author(s): Bradwell AR(1), Myers SD(2), Beazley M(3), Ashdown K(2), Harris NG(4), Bradwell
SB(5), Goodhart J(6), Imray CH(7), Wimalasena Y(8), Edsell ME(9), Pattinson
KT(10), Wright AD(11), Harris SJ(12); Birmingham Medical Research Expeditionary
Society.
Affiliation(s): Author information:
(1)School of Medicine, University of Birmingham, Birmingham (Drs Bradwell and
Wright). Electronic address: a.r.bradwell@bham.ac.uk. (2)Department of Sport &
Exercise Sciences, University of Chichester, Chichester (Dr Myers and Ms
Ashdown). (3)Spencer Street Surgery, Carlisle (Dr Beazley). (4)Merrist Wood
College Worplesdon Guildford (Mr Harris). (5)University College London, London
(Ms Bradwell). (6)The University of Warwick, Coventry (Mr Goodhart and Dr Imray).
(7)The University of Warwick, Coventry (Mr Goodhart and Dr Imray); University
Hospital Coventry and Warwickshire NHS Trust, Coventry (Drs Imray and
Wimalasena). (8)University Hospital Coventry and Warwickshire NHS Trust, Coventry
(Drs Imray and Wimalasena). (9)St George's Healthcare NHS Trust, London (Dr
Edsell). (10)Nuffield Department of Clinical Neurosciences, University of Oxford,
John Radcliffe Hospital, Oxford (Dr Pattinson). (11)School of Medicine,
University of Birmingham, Birmingham (Drs Bradwell and Wright). (12)QinetiQ,
Farnborough (Mr Harris), United Kingdom.
Publication date & source: 2014, Wilderness Environ Med. , 25(3):272-7
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.
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