Human muscle net K+ release during exercise is unaffected by elevated anaerobic metabolism, but reduced after prolonged acclimatization to 4100 m
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Human muscle net K+ release during exercise is unaffected by elevated anaerobic metabolism, but reduced after prolonged acclimatization to 4100 m. / Nordsborg, Nikolai Baastrup; Calbet, Jose A. L.; Sander, Mikael; van Hall, Gerrit; Juel, Carsten; Saltin, Bengt; Lundby, Carsten.
In: American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, Vol. 299, No. 1, 2010, p. R306-R313.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Human muscle net K+ release during exercise is unaffected by elevated anaerobic metabolism, but reduced after prolonged acclimatization to 4100 m
AU - Nordsborg, Nikolai Baastrup
AU - Calbet, Jose A. L.
AU - Sander, Mikael
AU - van Hall, Gerrit
AU - Juel, Carsten
AU - Saltin, Bengt
AU - Lundby, Carsten
N1 - CURIS 2010 5200 059
PY - 2010
Y1 - 2010
N2 - 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.
AB - 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.
U2 - 10.1152/ajpregu.00062.2010
DO - 10.1152/ajpregu.00062.2010
M3 - Journal article
C2 - 20410475
VL - 299
SP - R306-R313
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6119
IS - 1
ER -
ID: 19437164