In order to test the effect of artificially induced alkalosis and acidosis on the appearance of plasma lactate and work production, six well-trained oarsmen (age = 23.8 +/- 2.5 years; mass = 82.0 +/- 7.5 kg) were tested on three separate occasions after ingestion of 0.3 g.kg-1. NH4Cl (acidotic), NaHCO3 (alkalotic) or a placebo (control). Blood was taken from a forearm vein immediately prior to exercise for determination of pH and bicarbonate. One hour following the ingestion period, subjects rowed on a stationary ergometer at a pre-determined sub-maximal rate for 4 min, then underwent an immediate transition to a maximal effort for 2 min. Blood samples from an indwelling catheter placed in the cephalic vein were taken at rest and every 30 s during the 6 min exercise period as well as at 1, 3, 6, 9, 12, 15, 18, 21, 25 and 30 min during the passive recovery period. Pre-exercise blood values demonstrated significant differences (p less than 0.01) in pH and bicarbonate in all three conditions. Work outputs were unchanged in the submaximal test and in the maximal test (p greater than 0.05), although a trend toward decreased production was evident in the acidotic condition. Analysis of exercise blood samples using ANOVA with repeated measures revealed that the linear increase in plasma lactate concentration during control was significantly greater than acidosis (p less than 0.01). Although plasma lactate values during alkalosis were consistently elevated above control there was no significant difference in the linear trend (p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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