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Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-34593

Nordsborg, N B; Calbet, J A L; Sander, M; van Hall, G; Juel, C; Saltin, B; Lundby, C (2010). Human muscle net K+ release during exercise is unaffected by elevated anaerobic metabolism, but reduced after prolonged acclimatization to 4100 m. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, 299(1):R306-R313.

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Abstract

It was investigated if skeletal muscle K(+) release is linked to the degree of anaerobic energy production. Six subjects performed an incremental bicycle exercise test in normoxic and hypoxic conditions prior to and after 2 and 8 weeks of acclimatization to 4100 m. The highest workload completed by all subjects in all trials was 260 W. With acute hypoxic exposure prior to acclimatization, venous plasma [K(+)] was lower (P<0.05) in normoxia (4.9+/-0.1 mM) than hypoxia (5.2+/-0.2 mM) at 260 W, but similar at exhaustion which occurred at 400+/-9 W and 307+/-7 W (P<0.05), respectively. At the same absolute exercise intensity, leg net K(+) release was unaffected by hypoxic exposure independent of acclimatization. After 8 weeks of acclimatization no difference existed in venous plasma [K(+)] between the normoxic and hypoxic trial, neither at submaximal intensities nor at exhaustion (360+/-14 W vs. 313+/-8 W; P<0.05). At the same absolute exercise intensity, leg net K(+) release was less (P<0.001) than prior to acclimatization and reached negative values in both hypoxic and normoxic conditions after acclimatization. Moreover, the reduction in plasma volume during exercise relative to rest was higher (P<0.01) in normoxic than hypoxic conditions, irrespective of the degree of acclimatization (at 260 W prior to acclimatization: -10.0+/-0.4 % in normoxia and -4.9+/-0.8 % in hypoxia). It is concluded that leg net K(+) release is unrelated to anaerobic energy production and that acclimatization reduces leg net K(+) release during exercise.

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Center for Integrative Human Physiology
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
DDC:570 Life sciences; biology
610 Medicine & health
Language:English
Date:July 2010
Deposited On:05 Jul 2010 14:18
Last Modified:24 Dec 2013 02:14
Publisher:American Physiological Society
ISSN:0363-6119
Publisher DOI:10.1152/ajpregu.00062.2010
PubMed ID:20410475
Citations:Web of Science®. Times Cited: 2
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