Acclimatization improves submaximal exercise economy at 5533m

Latshang, TD; Turk, AJ; Hess, T; Schoch, OD; Bosch, MM; Barthelmes, D; Merz, Tobias Michael; Hefti, U; Pichler Hefti, J; Maggiorini, M; Bloch, KE (2013). Acclimatization improves submaximal exercise economy at 5533m. Scandinavian journal of medicine & science in sports, 23(4), pp. 458-467. Oxford: Wiley-Blackwell 10.1111/j.1600-0838.2011.01403.x

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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 Mt. Muztagh Ata. Maximal work rate (Wmax) 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 (VO2max) were 50.7 ± 9.5, 26.3 ± 5.6, 24.7 ± 7.0 mL/min/kg (P = 0.0001 5533 m vs 490 m). On days 6–7 (5533 m), VO2 at 75% Wmax (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, VO2 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 VO2 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.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Intensive Care, Emergency Medicine and Anaesthesiology (DINA) > Clinic of Intensive Care
04 Faculty of Medicine > Department of Gastro-intestinal, Liver and Lung Disorders (DMLL) > Clinic of Pneumology

UniBE Contributor:

Merz, Tobias Michael and Pichler Hefti, Jacqueline Renée

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0905-7188

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:19

Last Modified:

04 Jul 2014 08:39

Publisher DOI:

10.1111/j.1600-0838.2011.01403.x

Web of Science ID:

000321760100015

URI:

https://boris.unibe.ch/id/eprint/6378 (FactScience: 211339)

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