Journal of Applied Physiology, Vol 62, Issue 3 983-988, Copyright © 1987 by American Physiological Society

ARTICLES

Improvements in exercise performance: effects of carbohydrate feedings and diet

P. D. Neufer, D. L. Costill, M. G. Flynn, J. P. Kirwan, J. B. Mitchell and J. Houmard

In an effort to determine the effects of carbohydrate (CHO) feedings immediately before exercise in both the fasted and fed state, 10 well-trained male cyclists [maximum O2 consumption (VO2 max), 4.35 +/- 0.11 l/min)] performed 45 min of cycling at 77% VO2 max followed by a 15-min performance ride on an isokinetic cycle ergometer. After a 12-h fast, subjects ingested 45 g of liquid carbohydrate (LCHO), solid carbohydrate confectionery bar (SCHO), or placebo (P) 5 min before exercise. An additional trial was performed in which a high-CHO meal (200 g) taken 4 h before exercise was combined with a confectionery bar feeding (M + SCHO) immediately before the activity. At 10 min of exercise, serum glucose values were elevated by 18 and 24% during SCHO and LCHO, respectively, compared with P. At 0 and 45 min no significant differences were observed in muscle glycogen concentration or total use between the four trials. Total work produced during the final 15 min of exercise was significantly greater (P less than 0.05) during M + SCHO (194,735 +/- 9,448 N X m), compared with all other trials and significantly greater (P less than 0.05) during LCHO and SCHO (175,204 +/- 11,780 and 176,013 +/- 10,465 N X m, respectively) than trial P (159,143 +/- 11,407 N X m). These results suggest that, under conditions when CHO stores are less than optimal, exercise performance is enhanced with the ingestion of 45 g of CHO 5 min before 1 h of intense cycling.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				E. S. Chambers, M. W. Bridge, and D. A. Jones Carbohydrate sensing in the human mouth: effects on exercise performance and brain activity J. Physiol., April 15, 2009; 587(8): 1779 - 1794. [Abstract] [Full Text] [PDF]

				C. S. Fulco, K. W. Kambis, A. L. Friedlander, P. B. Rock, S. R. Muza, and A. Cymerman Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude J Appl Physiol, September 1, 2005; 99(3): 867 - 876. [Abstract] [Full Text] [PDF]

				S.-L. Wee, C. Williams, K. Tsintzas, and L. Boobis Ingestion of a high-glycemic index meal increases muscle glycogen storage at rest but augments its utilization during subsequent exercise J Appl Physiol, August 1, 2005; 99(2): 707 - 714. [Abstract] [Full Text] [PDF]

				V. A. Lacombe, K. W. Hinchcliff, R. J. Geor, and C. R. Baskin Muscle glycogen depletion and subsequent replenishment affect anaerobic capacity of horses J Appl Physiol, October 1, 2001; 91(4): 1782 - 1790. [Abstract] [Full Text] [PDF]

				F. Bequet, M. Peres, D. Gomez-Merino, M. Berthelot, P. Satabin, C. Pierard, and C. Y. Guezennec Simultaneous NMR microdialysis study of brain glucose metabolism in relation to fasting or exercise in the rat J Appl Physiol, June 1, 2000; 88(6): 1949 - 1954. [Abstract] [Full Text] [PDF]

				R. G. Fritzsche, T. W. Switzer, B. J. Hodgkinson, S.-H. Lee, J. C. Martin, and E. F. Coyle Water and carbohydrate ingestion during prolonged exercise increase maximal neuromuscular power J Appl Physiol, February 1, 2000; 88(2): 730 - 737. [Abstract] [Full Text] [PDF]

				D. J. Angus, M. Hargreaves, J. Dancey, and M. A. Febbraio Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance J Appl Physiol, January 1, 2000; 88(1): 113 - 119. [Abstract] [Full Text] [PDF]

				L. M. Burke, A. Claassen, J. A. Hawley, and T. D. Noakes Carbohydrate intake during prolonged cycling minimizes effect of glycemic index of preexercise meal J Appl Physiol, December 1, 1998; 85(6): 2220 - 2226. [Abstract] [Full Text] [PDF]

				H. A. Whitley, S. M. Humphreys, I. T. Campbell, M. A. Keegan, T. D. Jayanetti, D. A. Sperry, D. P. MacLaren, T. Reilly, and K. N. Frayn Metabolic and performance responses during endurance exercise after high-fat and high-carbohydrate meals J Appl Physiol, August 1, 1998; 85(2): 418 - 424. [Abstract] [Full Text] [PDF]

				J. P. Kirwan, D. O'Gorman, and W. J. Evans A moderate glycemic meal before endurance exercise can enhance performance J Appl Physiol, January 1, 1998; 84(1): 53 - 59. [Abstract] [Full Text] [PDF]

				B. Tamis-Jortberg, D. A. Downs JR, and M. E. Colten Effects of a Glucose Polymer Sports Drink on Blood Glucose, Insulin, and Performance in Subjects With Diabetes The Diabetes Educator, January 1, 1996; 22(5): 471 - 480. [PDF]