Acute hypoxia alters lactate threshold in chronic altitude residents

Astorino, T.A., Ghiasvand, F., & Robergs, R.A. (2004) Acute hypoxia alters lactate threshold in chronic altitude residents. Journal of Exercise Physiology Online, 7(2), pp. 6-15.

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Abstract

At an identical workload, blood lactate concentration ([La]) is higher in acute hypoxia (H) versus normoxia (N). However, in altitude-acclimatized individuals, the lactate response to incremental exercise in H and with various VO2max protocols is less clear. Subjects (N = 16) residing at moderate altitude completed VO2max tests on a cycle ergometer in N and H (FIO2 = 0.15) using ramp (R) and step (S) protocols. Gas exchange data were obtained breath-by-breath during exercise. Blood samples were obtained for measurement of blood [La]. One-way ANOVA with repeated measures was used to examine differences between lactate threshold (LT) and blood [La] among the various protocols. LT was significantly higher (p<0.05) in S (68.1 ? 8.9 %VO2max) and H (67.2 ? 9.6 %VO2max) versus R (59.7 ? 8.9 %VO2max). At VO2max, blood [La] was higher (p>0.05) in R compared to S and H. At 50 %VO2max, blood [La] was significantly higher (p<0.05) in S (2.0 ? 0.4 mmol/L) compared to R (1.7 ? 0.3 mmol/L and H (1.7 ? 0.6 mmol/L). In subjects acclimatized to altitude, the type of protocol used and gas fraction inspired alter the lactate response to incremental exercise. A standardized protocol for LT assessment is recommended to decrease discrepancies in LT between studies.

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ID Code: 96867
Item Type: Journal Article
Refereed: Yes
Additional Information: cited By 0
Keywords: lactic acid, adult; altitude; altitude acclimatization; analysis of variance; article; bicycle ergometer; controlled study; exercise; female; gas exchange; human; human experiment; hypoxia; lactate blood level; male; normal human; oxygen consumption; standardization
ISSN: 1097-9751
Copyright Owner: Copyright 2004 American Society of Exercise Physiologists
Deposited On: 22 Jul 2016 01:02
Last Modified: 22 Jul 2016 01:02

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