HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hughson, R L Search for Related Content PubMed PubMed Citation Articles by Hughson, R L

The effects of beta-adrenergic receptor blockade (100 mg oral metoprolol) or matched placebo on gas exchange kinetics were studied in six males. Ventilation and gas exchange were monitored in four transitions for each treatment from loadless pedalling (0 W) to a selected work rate (100 W) and back to 0 W. Breath-by-breath data were averaged for analysis. Oxygen uptake (VO2) kinetics were significantly slowed at the onset of exercise and recovery by beta-blockade. This resulted in larger oxygen deficit and oxygen debt (671 +/- 115, 586 +/- 87 ml O2, respectively) for beta-blockade than for placebo (497 +/- 87, 474 +/- 104 ml O2). In addition, oxygen deficit was significantly larger than oxygen debt during beta-blockade tests. These results can be explained by greater utilization of oxygen and creatine phosphate stores as well as anaerobic glycolysis at the onset of 100 W exercise with beta-blockade. Carbon dioxide output (VCO2) kinetics were significantly slowed by beta-blockade only at the onset of exercise. Expired ventilation (VE) kinetics were not affected by beta-blockade. At 0 W, VE was significantly reduced by beta-blockade. Heart rate was lower at all times with beta-blockade. Kinetics of heart rate were not affected. These data for VO2 kinetics at the start and end of exercise indicate that even in moderate-intensity exercise, lactic acid production can contribute significantly to energy supply. The use of the term ' alactic ' to describe the deficit and debt associated with this exercise is not appropriate.

This article has been cited by other articles:

				B. W. Scheuermann and T. J. Barstow O2 uptake kinetics during exercise at peak O2 uptake J Appl Physiol, November 1, 2003; 95(5): 2014 - 2022. [Abstract] [Full Text] [PDF]

				M. Endo, S. Tauchi, N. Hayashi, S. Koga, H. B. Rossiter, and Y. Fukuba Facial cooling-induced bradycardia does not slow pulmonary V.O2 kinetics at the onset of high-intensity exercise J Appl Physiol, October 1, 2003; 95(4): 1623 - 1631. [Abstract] [Full Text] [PDF]

				Y. Taniguchi, K. Ueshima, I. Chiba, I. Segawa, N. Kobayashi, M. Saito, and K. Hiramori A New Method Using Pulmonary Gas-Exchange Kinetics To Evaluate Efficacy of {beta}-Blocking Agents in Patients With Dilated Cardiomyopathy Chest, September 1, 2003; 124(3): 954 - 961. [Abstract] [Full Text] [PDF]

				M. Burnley, A. M. Jones, R. L. Hughson, N. Tordi, and S. Perrey Interpreting VO2 kinetics in heavy exercise revisited J Appl Physiol, June 1, 2003; 94(6): 2548 - 2550. [Full Text] [PDF]

				M. J. MacDonald, H. L. Naylor, M. E. Tschakovsky, and R. L. Hughson Peripheral circulatory factors limit rate of increase in muscle O2 uptake at onset of heavy exercise J Appl Physiol, January 1, 2001; 90(1): 83 - 89. [Abstract] [Full Text] [PDF]

				M. Burnley, A. M. Jones, H. Carter, and J. H. Doust Effects of prior heavy exercise on phase II pulmonary oxygen uptake kinetics during heavy exercise J Appl Physiol, October 1, 2000; 89(4): 1387 - 1396. [Abstract] [Full Text] [PDF]

				J. Bangsbo, P. Krustrup, J. Gonzalez-Alonso, R. Boushel, and B. Saltin Muscle oxygen kinetics at onset of intense dynamic exercise in humans Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2000; 279(3): R899 - R906. [Abstract] [Full Text] [PDF]

				M. E. Tschakovsky and R. L. Hughson Interaction of factors determining oxygen uptake at the onset of exercise J Appl Physiol, April 1, 1999; 86(4): 1101 - 1113. [Abstract] [Full Text] [PDF]

				N. Hayashi, A. Tanaka, M. Ishihara, and T. Yoshida Delayed vagal withdrawal slows circulatory but not oxygen uptake responses at work increase Am J Physiol Regulatory Integrative Comp Physiol, May 1, 1998; 274(5): R1268 - R1273. [Abstract] [Full Text] [PDF]

				M. Macdonald, P. K. Pedersen, and R. L. Hughson Acceleration of VO2 kinetics in heavy submaximal exercise by hyperoxia and prior high-intensity exercise J Appl Physiol, October 1, 1997; 83(4): 1318 - 1325. [Abstract] [Full Text] [PDF]

				R. L. Hughson, J. K. Shoemaker, M. E. Tschakovsky, and J. M. Kowalchuk Dependence of muscle VO2 on blood flow dynamics at onset of forearm exercise J Appl Physiol, October 1, 1996; 81(4): 1619 - 1626. [Abstract] [Full Text] [PDF]

				A. Cohen-Solal, T. Laperche, D. Morvan, M. Geneves, B. Caviezel, and R. Gourgon Prolonged Kinetics of Recovery of Oxygen Consumption After Maximal Graded Exercise in Patients With Chronic Heart Failure : Analysis With Gas Exchange Measurements and NMR Spectroscopy Circulation, June 15, 1995; 91(12): 2924 - 2932. [Abstract] [Full Text]