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


     

J Appl Physiol 61: 654-659, 1986;
8750-7587/86 $5.00
This Article
Right arrow Full Text (PDF)
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 Loy, S. F.
Right arrow Articles by Fisher, A. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Loy, S. F.
Right arrow Articles by Fisher, A. G.

Journal of Applied Physiology, Vol 61, Issue 2 654-659, Copyright © 1986 by American Physiological Society

ARTICLES

Effects of 24-hour fast on cycling endurance time at two different intensities

S. F. Loy, R. K. Conlee, W. W. Winder, A. G. Nelson, D. A. Arnall and A. G. Fisher

Ten competitive cyclists were exercised to exhaustion to test the potential of a 24-h fast for increasing endurance. One group (n = 4) was tested at an initial intensity of 86% maximum O2 uptake (VO2max) (HI) and a second group (n = 6) at 79% VO2max (MI). Both groups repeated test rides in fasted and normal-diet conditions. Time to fatigue was designated at two points: fatigue 1 occurred when pedal frequency could not be maintained at the initial percent VO2max; fatigue 2 occurred when pedal frequency could not be maintained at a workload of approximately 65% VO2max. In both HI and MI the 24-h fast had no effect on resting muscle glycogen stores but significantly increased plasma free fatty acid (FFA) levels. Despite the increased FFA availability, time to fatigue was reduced in the fasted groups. Fatigue 1 and 2 times (mean +/- SE) for HI-fasted were 42.0 +/- 6.2 and 170.0 +/- 20.4 min, respectively, compared with those of the HI-normal diet of 115.3 +/- 25.6 and 201.0 +/- 14.8 min. Fatigue 1 and 2 times for MI-fasted were 142.0 +/- 19.6 and 167.5 +/- 10.5 min compared with those of the MI-normal diet of 191.3 +/- 25.0 and 214.3 +/- 18.9 min. The cause of fatigue at fatigue 1 was not readily apparent. Fatigue 2 in all groups seemed to be related to hypoglycemia as well as muscle glycogen depletion.


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
P. N. Ainslie, I. T. Campbell, K. N. Frayn, S. M. Humphreys, D. P. M. MacLaren, and T. Reilly
Physiological, metabolic, and performance implications of a prolonged hill walk: influence of energy intake
J Appl Physiol, March 1, 2003; 94(3): 1075 - 1083.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
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]

Home page
 J. Appl. Physiol.Home page
H. W. Goforth, Jr., D. A. Arnall, B. L. Bennett, and P. G. Law
Persistence of supercompensated muscle glycogen in trained subjects after carbohydrate loading
J Appl Physiol, January 1, 1997; 82(1): 342 - 347.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online