Int J Sports Med 1984; 05(2): 107-110
DOI: 10.1055/s-2008-1025890
© Georg Thieme Verlag Stuttgart · New York

Maximal Exercise Tolerance After Induced Alkalosis

A. Katz, D. L. Costill, D. S. King, M. Hargreaves, W. J. Fink
  • Human Performance Laboratory, Ball State University, Muncie, IN 47306, U.S.A.
Further Information

Publication History

Publication Date:
14 March 2008 (online)

Abstract

Eight healthy males performed two rides to exhaustion at a work load corresponding to 125 V̇O2 max, 1 h after ingesting either 0.2 g NaHCO3/kg body weight (E) or NaCI (C). Mean ± SE pre-exercise blood pH, HCO- 3, and base excess (BE) values were respectively 7.42 ± 0.01, 28.2 ± 1.5 mmol/l, and 2.02 ± 0.10 mmol/l for the E condition, and 7.39 ± 0.01, 24.4 ± 0.07 mmol/l, and -0.40 ± 0.07 mmol/l for the C condition (P < 0.05 for all variables). Cycling time to exhaustion (E = 100.6 ± 6.1; C = 98.6 ± 5.7 s) and total V̇O2 during recovery (E = 17.7 ± 0.9; C = 17.3 ± 0.8 I/30 min) did not differ significantly between treatments. Blood pH, HCO- 3, and BE were significantly higher while the hydrogen ion to lactate ratio (nmol/mmol) was significantly lower in E than in C during recovery. Blood LA levels were also greater in E than in C during the latter part of recovery although peak individual values were not significantly different between trials (E = 14.4 ± 0.4; C = 13.3 ± 0.0 mmol/l). In view of the insignificant differences in cycling time, peak individual LA, and total recovery V̇O2, it is not likely that LA production was greater in E than in C. Rather it appears that LA efflux was enhanced by the NaHCO3 feeding. Additionally, the return of the acid-base status in blood to resting conditions was more rapid during alkalosis. Given this protocol, alkalosis does not help to sustain an intense exercise bout. These data suggest, however, that NaHCO3 may be of benefit following repeated work bouts.

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