Maximal exercise tolerance after induced alkalosis

Abstract

Eight healthy males performed two rides to exhaustion at a work load corresponding to 125% Q02 max, one hr after ingesting either NaHCO3 (E) or NaCl (C). Mean + SE pre-exercise blood pH, HCO3 and base excess (BE) values were respectively 7.42 + 0.01, 28.2 + 1.5 mmol/l and 2.02 + 0.1 mmol/l for the E condition, and 7.39 + 0.01, 24.4 + 0.7 mmol/l and -0.4 + 0.7 mmol/l for the C condition (P < 0.05 for all variables). Cycling time to exhaustion (E = 100.66.1; C = 98.6 + 5.7 sec) and total "02 during recovery (E 17.7 + 0.9; C = 17.3 + 0.8 1/30 min) did not differ between treatments. Blood pH, HCO3 and BE were significantly higher while the hydrogen ion to lactate ratio (LH+I/ELAI) 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 CE = 14.4 + 0.4; C = 13.3 + 0.0 mmol /1) . In view of the insignificant differences in cycling time, peakLA production was greater in E than in C. Rather it individual LA and total recovery 002, it is not likely that Given this protocol, alkalosis does not help to sustain an 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 does not help to sustain an intense exercise bout. These data suggest, however, that NaHCO3 may be of benefit following repeated work bouts.Thesis (M.A.