AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 4 891-R899, Copyright © 1992 by American Physiological Society

ARTICLES

Elevated muscle acidity and energy production during exhaustive exercise in humans

J. Bangsbo, T. Graham, L. Johansen, S. Strange, C. Christensen and B. Saltin
August Krogh Institute, Copenhagen, Denmark.

This study examined the effect of previous intense exercise on energy production during exhaustive exercise. Subjects (n = 6) performed dynamic knee extensor exercise to exhaustion twice (Ex1 and Ex2) separated by 16 min of recovery consisting of 10 min of rest, 3.5 min of very high-intensity intermittent exercise, and a further 2.5 min of rest. This resulted in an elevated muscle lactate concentration of 13.1 mmol/kg wet wt before Ex2. Muscle lactate concentration was the same at end of Ex1 and Ex2, but the accumulation of lactate and net lactate release during Ex2 was reduced (P < 0.05) by 67 and 38%, respectively. The time to exhaustion was 3.73 and 2.98 min, respectively, and the mean rate of net lactate production for Ex2 was lower (P < 0.05) than for Ex1 (4.6 +/- 1.2 and 9.6 +/- 1.7 mmol.min-1.kg wet wt-1, respectively). Leg O2 uptake was the same for Ex1 and Ex2. Muscle pH (6.85) was lowered (P < 0.05) before Ex2, but at the end of Ex2 (6.77) it tended (P < 0.1) to be higher compared with that at the end of Ex1 (6.73). In summary, the net lactate production rate is reduced but the aerobic energy production is not significantly altered when intense exercise is repeated. Fatigue and the lowered glycolysis do not appear to be caused by the elevated acidity per se before exercise.

This article has been cited by other articles:

				D. G. Allen, G. D. Lamb, and H. Westerblad Skeletal Muscle Fatigue: Cellular Mechanisms Physiol Rev, January 1, 2008; 88(1): 287 - 332. [Abstract] [Full Text] [PDF]

				G. D. Lamb, D. G. Stephenson, J. Bangsbo, and C. Juel Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity J Appl Physiol, April 1, 2006; 100(4): 1410 - 1412. [Full Text] [PDF]

				S. M. Sostaric, t. l. S. L. Skinner, M. J. Brown, T. Sangkabutra, I. Medved, T. Medley, S. E. Selig, I. Fairweather, D. Rutar, and M. J. McKenna Alkalosis increases muscle K+ release, but lowers plasma [K+] and delays fatigue during dynamic forearm exercise J. Physiol., January 1, 2006; 570(1): 185 - 205. [Abstract] [Full Text] [PDF]

				N. Nordsborg, M. Mohr, L. D. Pedersen, J. J. Nielsen, H. Langberg, and J. Bangsbo Muscle interstitial potassium kinetics during intense exhaustive exercise: effect of previous arm exercise Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2003; 285(1): R143 - R148. [Abstract] [Full Text] [PDF]

				J. Baldwin, R. J. Snow, M. J. Gibala, A. Garnham, K. Howarth, and M. A. Febbraio Glycogen availability does not affect the TCA cycle or TAN pools during prolonged, fatiguing exercise J Appl Physiol, June 1, 2003; 94(6): 2181 - 2187. [Abstract] [Full Text] [PDF]

				B. Op 't Eijnde, M. Van Leemputte, F. Brouns, G. J. Van Der Vusse, V. Labarque, M. Ramaekers, R. Van Schuylenberg, P. Verbessem, H. Wijnen, and P. Hespel No effects of oral ribose supplementation on repeated maximal exercise and de novo ATP resynthesis J Appl Physiol, November 1, 2001; 91(5): 2275 - 2281. [Abstract] [Full Text] [PDF]

				B. Norman, R. L. Sabina, and E. Jansson Regulation of skeletal muscle ATP catabolism by AMPD1 genotype during sprint exercise in asymptomatic subjects J Appl Physiol, July 1, 2001; 91(1): 258 - 264. [Abstract] [Full Text] [PDF]

				T. E. Graham, K. B. Adamo, J. Shearer, I. Marchand, and B. Saltin Pro- and macroglycogenolysis: relationship with exercise intensity and duration J Appl Physiol, March 1, 2001; 90(3): 873 - 879. [Abstract] [Full Text] [PDF]

				O. M. Sejersted and G. Sjogaard Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise Physiol Rev, October 1, 2000; 80(4): 1411 - 1481. [Abstract] [Full Text] [PDF]

				C. Juel, H. Pilegaard, J. J. Nielsen, and J. Bangsbo Interstitial K+ in human skeletal muscle during and after dynamic graded exercise determined by microdialysis Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2000; 278(2): R400 - R406. [Abstract] [Full Text] [PDF]

				L. J. McCutcheon, R. J. Geor, and K. W. Hinchcliff Effects of prior exercise on muscle metabolism during sprint exercise in horses J Appl Physiol, November 1, 1999; 87(5): 1914 - 1922. [Abstract] [Full Text] [PDF]

				M. L. Parolin, A. Chesley, M. P. Matsos, L. L. Spriet, N. L. Jones, and G. J. F. Heigenhauser Regulation of skeletal muscle glycogen phosphorylase and PDH during maximal intermittent exercise Am J Physiol Endocrinol Metab, November 1, 1999; 277(5): E890 - E900. [Abstract] [Full Text] [PDF]

				F. Greer, C. McLean, and T. E. Graham Caffeine, performance, and metabolism during repeated Wingate exercise tests J Appl Physiol, October 1, 1998; 85(4): 1502 - 1508. [Abstract] [Full Text] [PDF]

				J. D. Bruton, J. Lannergren, and H. Westerblad Effects of CO2-induced acidification on the fatigue resistance of single mouse muscle fibers at 28°C J Appl Physiol, August 1, 1998; 85(2): 478 - 483. [Abstract] [Full Text] [PDF]

				M. Hargreaves, M. J. McKenna, D. G. Jenkins, S. A. Warmington, J. L. Li, R. J. Snow, and M. A. Febbraio Muscle metabolites and performance during high-intensity, intermittent exercise J Appl Physiol, May 1, 1998; 84(5): 1687 - 1691. [Abstract] [Full Text] [PDF]