Journal of Applied Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

J Appl Physiol (June 27, 2003). doi:10.1152/japplphysiol.01220.2001
This Article
Right arrow Full Text (PDF) Free
Right arrow All Versions of this Article:
95/4/1531    most recent
01220.2001v1
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Favret, F.
Right arrow Articles by Gonzalez, N. C
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Favret, F.
Right arrow Articles by Gonzalez, N. C
Submitted on December 12, 2001
Accepted on June 24, 2003

Effects of exercise training on acclimatization to hypoxia: systemic O2 transport during maximal exercise

Fabrice Favret1, Kyle K Henderson2, Jean-Paul Richalet1, and Norberto C Gonzalez2*

1 Association pour la Recherche en Physiologie de l'Environment, Laboratoire, Bobigny, France
2 Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160-7401, USA

* To whom correspondence should be addressed. E-mail: ngonzale{at}kumc.edu.

Acclimatization to hypoxia has minimal effect on maximal OM2 uptake(VO2max). Prolonged hypoxia shows reductions in cardiac output (Q max), decreased maximal heart rate (Hrmax), myocardial {beta} adrenoceptor ({beta}-AR) downregulation, and chronotropic response to isoproterenol. This study tested the hypothesis that exercise training (ET), which attenuates {beta}-AR downregulation, would increase Hrmax and Qmax of acclimatization, and result in higher VO2max. After 3 weeks of ET, rats lived at PIo2 70 Torr for 10 days (acclimatized trained) or remained in normoxia (non acclimatized trained) while both groups continued to train in normoxia. Controls were sedentary acclimatized and non acclimatized rats. All rats exercised maximally in normoxia and hypoxia. Myocardial {beta}-AR density and isoproterenol-induced Hrmax were reduced, and cholinergic receptor (M-Ach) density was increased after acclimatization; all of these changes were reversed by ET. Normoxic VO2max (ml/(min.kg)) was 95.8±1.0 in acclimatized trained (n=6); 87.7± 1.7 in non acclimatized trained (n=6 p<0.05); 74.2±1.4 in acclimatized sedentary (n=6 p<0.05); and 72.5± 1.2 in non-acclimatized sedentary (n=8; and p>0.05 acclimatized vs non acclimatized sedentary). A similar distribution of VO2max values occurred in hypoxic exercise. Qmaxwas highest in trained acclimatized and non acclimatized, intermediate in non acclimatized sedentary, and lowest in acclimatiaed sedentary. ET preserved Qmax in acclimatized rats thanks to maintenance of Hrmax, as well as of maximal stroke volume. Qmax preservation, coupled with a higher Cao2, resulted in acclimatized trained rats having the highest To2max and VO2max. These results show that exercise training attenuates {beta}-AR downregulation and preservesQmax and VO2max after acclimatization, and support the idea that {beta}-AR downregulation partially contributes to the limitation ofVO2max after acclimatization in rats.




This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
N. C. Gonzalez, S. D. Kirkton, R. A. Howlett, S. L. Britton, L. G. Koch, H. E. Wagner, and P. D. Wagner
Continued divergence in VO2 max of rats artificially selected for running endurance is mediated by greater convective blood O2 delivery
J Appl Physiol, November 1, 2006; 101(5): 1288 - 1296.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
F. Favret, K. K. Henderson, J. Allen, J.-P. Richalet, and N. C. Gonzalez
Exercise training improves lung gas exchange and attenuates acute hypoxic pulmonary hypertension but does not prevent pulmonary hypertension of prolonged hypoxia
J Appl Physiol, January 1, 2006; 100(1): 20 - 25.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
T. D. Noakes, P. E. di Prampero, C. Capelli, T. Zaobornyj, L. B Valdez, A. Boveris, M. Ashenden, T. W. Secomb, S. Dufour, E. Ponsot, et al.
Comments on Point:Counterpoint "Positive effects of intermittent hypoxia (live high:train low) on exercise performance are/are not mediated primarily by augmented red cell volume"
J Appl Physiol, December 1, 2005; 99(6): 2453 - 2462.
[Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
T. A. Orth, J. A. Allen, J. G. Wood, and N. C. Gonzalez
Exercise training prevents the inflammatory response to hypoxia in cremaster venules
J Appl Physiol, June 1, 2005; 98(6): 2113 - 2118.
[Abstract] [Full Text] [PDF]

Home page
 Exp. Biol. Med.Home page
J. F. Carroll, J. J. Thaden, and A. M. Wright
A Comparison of Two Exercise Training Programs on Cardiac Responsiveness to {beta}-Stimulation in Obesity
Experimental Biology and Medicine, March 1, 2005; 230(3): 180 - 188.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
C. Reboul, S. Tanguy, J. M. Juan, M. Dauzat, and P. Obert
Cardiac remodeling and functional adaptations consecutive to altitude training in rats: implications for sea level aerobic performance
J Appl Physiol, January 1, 2005; 98(1): 83 - 92.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 1966 by the American Physiological Society.