| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Journal of Applied Physiology, Vol 76, Issue 2 787-792, Copyright © 1994 by American Physiological Society
ARTICLES |
D. C. Poole, L. B. Gladden, S. Kurdak and M. C. Hogan
Department of Medicine, University of California at San Diego, La Jolla 92093-0623.
Constant-load exercise that engenders a sustained lactic acidosis (i.e., above the lactate threshold) is accompanied by a slow component of O2 uptake (VO2) kinetics that increases VO2 above rather than toward the predicted value. This response arises predominantly from within the exercising limbs and is temporally correlated with that of blood lactate. Lactate exerts a disproportionate metabolic stimulatory effect on gluconeogenic tissues, and there is a strong indication that lactate infusions may increase VO2 of resting tissues. To investigate the potential role of lactate in the VO2 slow component, we infused lactate in 20-min square-wave pulses (change of 10 mM) into the arterial blood supply of an electrically stimulated and surgically isolated dog gastrocnemius preparation (2 x 60-min bouts, approximately 30-40% peak VO2; n = 5) under iso-pH conditions at constant muscle temperature. With lactate infusions, intramuscular lactate concentration ([La]) rose proportionally with inflowing [La] (muscle [La] = 6.34 + 0.38 blood [La]; r = 0.642, P < 0.05) to approximately 80% of arterial blood [La], and neither blood (control, 7.39 +/- 0.01; high lactate, 7.40 +/- 0.01; P > 0.05) nor muscle (control, 7.02 +/- 0.03; high lactate, 7.00 +/- 0.04; P > 0.05) pH was changed. Compared with control values, lactate infusion decreased muscle VO2 from 5.1 +/- 0.3 to 4.1 +/- 0.2 ml.min-1.100 g-1 (P < 0.05). However, VO2 relative to tension remained constant. Notwithstanding the obvious differences between this preparation and the exercising human, this finding does not support a role for lactate per se in driving the VO2 slow component during intense exercise.
This article has been cited by other articles:
|
|
 |
|
  M. Burnley, J. H. Doust, and A. M. Jones Time required for the restoration of normal heavy exercise VO2 kinetics following prior heavy exercise J Appl Physiol, November 1, 2006; 101(5): 1320 - 1327. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A Osborne and D. A Schneider Muscle glycogen reduction in man: relationship between surface EMG activity and oxygen uptake kinetics during heavy exercise Exp Physiol, January 1, 2006; 91(1): 179 - 189. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Sahlin, J. B. Sorensen, L. B. Gladden, H. B. Rossiter, and P. K. Pedersen Prior heavy exercise eliminates VO2 slow component and reduces efficiency during submaximal exercise in humans J. Physiol., May 1, 2005; 564(3): 765 - 773. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H.-Y. Ong, C. S. O'Dochartaigh, S. Lovell, V. H. Patterson, K. Wasserman, D. P. Nicholls, and M. S. Riley Gas Exchange Responses to Constant Work-Rate Exercise in Patients with Glycogenosis Type V and VII Am. J. Respir. Crit. Care Med., June 1, 2004; 169(11): 1238 - 1244. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. B. Rossiter, S. A. Ward, F. A. Howe, J. M. Kowalchuk, J. R. Griffiths, and B. J. Whipp Dynamics of intramuscular 31P-MRS Pi peak splitting and the slow components of PCr and O2 uptake during exercise J Appl Physiol, December 1, 2002; 93(6): 2059 - 2069. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Hamann, K. M. Kelley, and L. B. Gladden Effect of epinephrine on net lactate uptake by contracting skeletal muscle J Appl Physiol, December 1, 2001; 91(6): 2635 - 2641. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A Ferguson, D. Ball, P. Krustrup, P. Aagaard, M. Kjaer, A. J Sargeant, Y. Hellsten, and J. Bangsbo Muscle oxygen uptake and energy turnover during dynamic exercise at different contraction frequencies in humans J. Physiol., October 1, 2001; 536(1): 261 - 271. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F Ozyener, H B Rossiter, S A Ward, and B J Whipp Influence of exercise intensity on the on- and off-transient kinetics of pulmonary oxygen uptake in humans J. Physiol., June 15, 2001; 533(3): 891 - 902. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Borrani, R. Candau, G. Y. Millet, S. Perrey, J. Fuchslocher, and J. D. Rouillon Is the {V}O2 slow component dependent on progressive recruitment of fast-twitch fibers in trained runners? J Appl Physiol, June 1, 2001; 90(6): 2212 - 2220. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Carter, A. M. Jones, T. J. Barstow, M. Burnley, C. Williams, and J. H. Doust Effect of endurance training on oxygen uptake kinetics during treadmill running J Appl Physiol, November 1, 2000; 89(5): 1744 - 1752. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Lucia, J. Hoyos, and J. L Chicharro The slow component of {V}O2 in professional cyclists Br. J. Sports Med., October 1, 2000; 34(5): 367 - 374. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Langsetmo and D. C. Poole VO2 recovery kinetics in the horse following moderate, heavy, and severe exercise J Appl Physiol, April 1, 1999; 86(4): 1170 - 1177. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Scheuermann, J. M. Kowalchuk, D. H. Paterson, and D. A. Cunningham O2 uptake kinetics after acetazolamide administration during moderate- and heavy-intensity exercise J Appl Physiol, October 1, 1998; 85(4): 1384 - 1393. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
