| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Journal of Applied Physiology, Vol 78, Issue 3 867-874, Copyright © 1995 by American Physiological Society
ARTICLES |
T. E. Graham and L. L. Spriet
School of Human Biology, University of Guelph, Ontario, Canada.
This study examined the exercise responses of well-trained endurance athletes to various doses of caffeine to evaluate the impact of the drug on exercise metabolism and endurance capacity. Subjects (n = 8) withdrew from all dietary sources of caffeine for 48 h before each of four tests. One hour before exercise they ingested capsules of placebo or caffeine (3, 6, or 9 mg/kg), rested quietly, and then ran at 85% of maximal O2 consumption to voluntary exhaustion. Blood samples for methylxanthine, catecholamine, glucose, lactate, free fatty acid, and glycerol analyses were taken every 15 min. Plasma caffeine concentration increased with each dose (P < 0.05). Its major metabolite, paraxanthine, did not increase between the 6 and 9 mg/kg doses, suggesting that hepatic caffeine metabolism was saturated. Endurance was enhanced with both 3 and 6 mg/kg of caffeine (increases of 22 +/- 9 and 22 +/- 7%, respectively; both P < 0.05) over the placebo time of 49.4 +/- 4.2 min, whereas there was no significant effect with 9 mg/kg of caffeine. In contrast, plasma epinephrine was not increased with 3 mg/kg of caffeine but was greater with the higher doses (P < 0.05). Similarly only the highest dose of caffeine resulted in increases in glycerol and free fatty acids (P < 0.05). Thus the highest dose had the greatest effect on epinephrine and blood-borne metabolites yet had the least effect on performance. The lowest dose had little or no effect on epinephrine and metabolites but did have an ergogenic effect. These results are not compatible with the traditional theory that caffeine mediates its ergogenic effect via enhanced catecholamines.
This article has been cited by other articles:
|
|
 |
|
  A. Bassini-Cameron, E. Sweet, A. Bottino, C. Bittar, C. Veiga, L.-C. Cameron, and E. H M Dantas Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions * COMMENTARY Br. J. Sports Med., August 1, 2007; 41(8): 523 - 530. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Whitham, G. J. Walker, and N. C. Bishop Effect of caffeine supplementation on the extracellular heat shock protein 72 response to exercise J Appl Physiol, October 1, 2006; 101(4): 1222 - 1227. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Mundel and D. A. Jones Effect of transdermal nicotine administration on exercise endurance in men Exp Physiol, July 1, 2006; 91(4): 705 - 713. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Kalmar and E. Cafarelli Central excitability does not limit postfatigue voluntary activation of quadriceps femoris J Appl Physiol, June 1, 2006; 100(6): 1757 - 1764. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. M Popkin, L. E Armstrong, G. M Bray, B. Caballero, B. Frei, and W. C Willett A new proposed guidance system for beverage consumption in the United States Am. J. Clinical Nutrition, March 1, 2006; 83(3): 529 - 542. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. B. Norager, M. B. Jensen, M. R. Madsen, and S. Laurberg Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study J Appl Physiol, December 1, 2005; 99(6): 2302 - 2306. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B.M. Meyers and E. Cafarelli Caffeine increases time to fatigue by maintaining force and not by altering firing rates during submaximal isometric contractions J Appl Physiol, September 1, 2005; 99(3): 1056 - 1063. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Murase, S. Haramizu, A. Shimotoyodome, A. Nagasawa, and I. Tokimitsu Green tea extract improves endurance capacity and increases muscle lipid oxidation in mice Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2005; 288(3): R708 - R715. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. J. Conway, R. Orr, and S. R. Stannard Effect of a divided caffeine dose on endurance cycling performance, postexercise urinary caffeine concentration, and plasma paraxanthine J Appl Physiol, April 1, 2003; 94(4): 1557 - 1562. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Davis, Z. Zhao, H. S. Stock, K. A. Mehl, J. Buggy, and G. A. Hand Central nervous system effects of caffeine and adenosine on fatigue Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2003; 284(2): R399 - R404. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. McLean and T. E. Graham Effects of exercise and thermal stress on caffeine pharmacokinetics in men and eumenorrheic women J Appl Physiol, October 1, 2002; 93(4): 1471 - 1478. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. G. Bell and T. M. McLellan Exercise endurance 1, 3, and 6 h after caffeine ingestion in caffeine users and nonusers J Appl Physiol, October 1, 2002; 93(4): 1227 - 1234. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Cox, B. Desbrow, P. G. Montgomery, M. E. Anderson, C. R. Bruce, T. A. Macrides, D. T. Martin, A. Moquin, A. Roberts, J. A. Hawley, et al. Effect of different protocols of caffeine intake on metabolism and endurance performance J Appl Physiol, September 1, 2002; 93(3): 990 - 999. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. S. L. Thong and T. E. Graham Caffeine-induced impairment of glucose tolerance is abolished by beta -adrenergic receptor blockade in humans J Appl Physiol, June 1, 2002; 92(6): 2347 - 2352. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. S.L. Thong, W. Derave, B. Kiens, T. E. Graham, B. Urso, J. F.P. Wojtaszewski, B. F. Hansen, and E. A. Richter Caffeine-Induced Impairment of Insulin Action but Not Insulin Signaling in Human Skeletal Muscle Is Reduced by Exercise Diabetes, March 1, 2002; 51(3): 583 - 590. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W. E. Rush and L. L. Spriet Skeletal muscle glycogen phosphorylase a kinetics: effects of adenine nucleotides and caffeine J Appl Physiol, November 1, 2001; 91(5): 2071 - 2078. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Tarnopolsky and C. Cupido Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine consumers J Appl Physiol, November 1, 2000; 89(5): 1719 - 1724. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Greer, D. Friars, and T. E. Graham Comparison of caffeine and theophylline ingestion: exercise metabolism and endurance J Appl Physiol, November 1, 2000; 89(5): 1837 - 1844. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. H. Van Soeren and T. E. Graham Effect of caffeine on metabolism, exercise endurance, and catecholamine responses after withdrawal J Appl Physiol, October 1, 1998; 85(4): 1493 - 1501. [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]
|
|
|
|
|
|
T. E. Graham, E. Hibbert, and P. Sathasivam Metabolic and exercise endurance effects of coffee and caffeine ingestion J Appl Physiol, September 1, 1998; 85(3): 883 - 889. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Mohr, M. Van Soeren, T. E. Graham, and M. Kjar Caffeine ingestion and metabolic responses of tetraplegic humans during electrical cycling J Appl Physiol, September 1, 1998; 85(3): 979 - 985. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. M. R. Kovacs, J. H. C. H. Stegen, and F. Brouns Effect of caffeinated drinks on substrate metabolism, caffeine excretion, and performance J Appl Physiol, August 1, 1998; 85(2): 709 - 715. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Chesley, R. A. Howlett, G. J. F. Heigenhauser, E. Hultman, and L. L. Spriet Regulation of muscle glycogenolytic flux during intense aerobic exercise after caffeine ingestion Am J Physiol Regulatory Integrative Comp Physiol, August 1, 1998; 275(2): R596 - R603. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
