Journal of Applied Physiology, Vol 55, Issue 1 225-229, Copyright © 1983 by American Physiological Society

ARTICLES

Effects of pH on maximal power output and fatigue during short-term dynamic exercise

N. McCartney, G. J. Heigenhauser and N. L. Jones

Six healthy subjects performed four exercise studies in random order on separate days: a control study, metabolic acidosis induced by ammonium chloride, metabolic alkalosis induced by sodium bicarbonate, and respiratory acidosis induced by 5% CO2 inhalation. The subjects exerted maximal force on the pedals of a constant-velocity cycle ergometer at 100 rpm for 30 s; torque was measured and power calculated. Arterialized venous blood was sampled, and plasma lactate concentrations was measured immediately after and at 2-min intervals for 10 min following exercise. Although maximal peak power and total work, for the 30-s test, were lower in the two acidosis conditions, this effect was not statistically significant. Plasma lactate 30-s postexercise was lower in metabolic acidosis (2.8 +/- 1.6 mmol X 1(-1) (mean +/- SD) and respiratory acidosis (1.5 +/- 0.8 mmol X 1(-1) than in placebo conditions (5.9 +/- 3.3 mmol X 1(-1) and metabolic alkalosis 7.8 +/- 4.2 mmol X 1(-1). These differences were maintained but lessened during 10 min of recovery. In contrast to previous studies, which showed a marked reduction in endurance time during sustained heavy exercise, reductions in blood pH are associated with only small reductions in the total work performed in 30 s of maximal exercise. A delayed and smaller accumulation of lactate in plasma was observed following exercise during acidosis.

This article has been cited by other articles:

				M. G. Hollidge-Horvat, M. L. Parolin, D. Wong, N. L. Jones, and G. J. F. Heigenhauser Effect of induced metabolic alkalosis on human skeletal muscle metabolism during exercise Am J Physiol Endocrinol Metab, February 1, 2000; 278(2): E316 - E329. [Abstract] [Full Text] [PDF]

				J. Stout, J. Eckerson, K. Ebersole, G. Moore, S. Perry, T. Housh, A. Bull, J. Cramer, and A. Batheja Effect of creatine loading on neuromuscular fatigue threshold J Appl Physiol, January 1, 2000; 88(1): 109 - 112. [Abstract] [Full Text] [PDF]

				M. G. Hollidge-Horvat, M. L. Parolin, D. Wong, N. L. Jones, and G. J. F. Heigenhauser Effect of induced metabolic acidosis on human skeletal muscle metabolism during exercise Am J Physiol Endocrinol Metab, October 1, 1999; 277(4): E647 - E658. [Abstract] [Full Text] [PDF]

				R. W. Light, M.-J. Peng, D. W. Stansbury, C. S. H. Sassoon, J. A. Despars, and C. K. Mahutte Effects of Sodium Bicarbonate Administration on the Exercise Tolerance of Normal Subjects Breathing Through Dead Space Chest, January 1, 1999; 115(1): 102 - 108. [Abstract] [Full Text] [PDF]

				L. D. Kesl and R. L. Engen Effects of NaHCO3 loading on acid-base balance, lactate concentration, and performance in racing greyhounds J Appl Physiol, September 1, 1998; 85(3): 1037 - 1043. [Abstract] [Full Text] [PDF]