Premium
Acclimatization improves submaximal exercise economy at 5533 m
Author(s) -
Latshang T. D.,
Turk A. J.,
Hess T.,
Schoch O. D.,
Bosch M. M.,
Barthelmes D.,
Merz T. M.,
Hefti U.,
Hefti J. Pichler,
Maggiorini M.,
Bloch K. E.
Publication year - 2013
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2011.01403.x
Subject(s) - acclimatization , running economy , medicine , physical medicine and rehabilitation , physical therapy , cardiology , biology , vo2 max , heart rate , ecology , blood pressure
We tested whether the better subjective exercise tolerance perceived by mountaineers after altitude acclimatization relates to enhanced exercise economy. Thirty‐two mountaineers performed progressive bicycle exercise to exhaustion at 490 m and twice at 5533 m (days 6–7 and day 11), respectively, during an expedition to M t. M uztagh A ta. Maximal work rate ( W max ) decreased from mean ± SD 356 ± 73 watts at 490 m to 191 ± 49 watts and 193 ± 45 watts at 5533 m, days 6–7 and day 11, respectively; corresponding maximal oxygen uptakes ( VO 2max ) were 50.7 ± 9.5, 26.3 ± 5.6, 24.7 ± 7.0 m L /min/kg ( P = 0.0001 5533 m vs 490 m). On days 6–7 (5533 m), VO 2 at 75% W max (152 ± 37 watts) was 1.75 ± 0.45 L /min, oxygen saturation 68 ± 8%. On day 11 (5533 m), at the same submaximal work rate, VO 2 was lower (1.61 ± 0.47 L /min, P < 0.027) indicating improved net efficiency; oxygen saturation was higher (74 ± 7%, P < 0.0004) but ratios of VO 2 to work rate increments remained unchanged. On day 11, mountaineers climbed faster from 4497 m to 5533 m than on days 5–6 but perceived less effort (visual analog scale 50 ± 15 vs 57 ± 20, P = 0.006) and reduced symptoms of acute mountain sickness. We conclude that the better performance and subjective exercise tolerance after acclimatization were related to regression of acute mountain sickness and improved submaximal exercise economy because of lower metabolic demands for non‐external work‐performing functions.