Document Detail

Running endurance in 27-h-fasted humans.
MedLine Citation:
PMID:  3325490     Owner:  NLM     Status:  MEDLINE    
Nine male marathon runners were exercised to exhaustion to determine the effects of a 27-h fast on endurance performance. Each subject completed two exercise tests at the same treadmill speed (set at 70% maximal O2 uptake), one following a 27-h fast and one 3 h after a preexercise meal, in random order. Fasting caused a 44.7 +/- 5.8% (SE) decrease in endurance performance (P less than 0.01). Blood, muscle, psychological, and ventilatory data were examined to determine the cause of the decreased performance. Fasting caused significant increases in O2 uptake (9.3 +/- 2.0%), heart rate (8.4 +/- 2.4%), and rating of perceived exertion, ventilation, and psychological fatigue, evident within the first 60 min of exercise. There were no differences in plasma glucose or epinephrine levels. Muscle glycogen degraded at the same rate (0.482 +/- 0.146 vs. 0.470 +/- 0.281 mumol.g-1.min-1 in the nonfasted and fasted tests, respectively) despite lower respiratory exchange ratio and elevated free fatty acid levels, which may partially explain the elevated O2 uptake. Lactate, insulin, and norepinephrine were all increased in the fasted test (P less than 0.05). The increase in norepinephrine (r = 0.79, P less than 0.01), the diameter of type I muscle fibers (r = 0.70, P less than 0.05), and ending insulin levels (r = -0.88, P less than 0.01) were correlated with endurance time in the fasted state. Fatigue in endurance running for 27-h fasted humans appears to be related to a combination of physiological, psychological, metabolic, and hormonal changes.
D C Nieman; K A Carlson; M E Brandstater; R T Naegele; J W Blankenship
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  63     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1987 Dec 
Date Detail:
Created Date:  1988-04-07     Completed Date:  1988-04-07     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2502-9     Citation Subset:  IM    
Center for Health Promotion, Loma Linda University, California 92350.
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MeSH Terms
Blood Glucose / analysis
Fasting* / psychology
Glucagon / blood
Glycogen / analysis
Heart Rate*
Insulin / blood
Lactates / blood
Muscles / analysis
Oxygen / physiology
Physical Endurance*
Time Factors
Grant Support
Reg. No./Substance:
0/Blood Glucose; 0/Insulin; 0/Lactates; 7782-44-7/Oxygen; 9005-79-2/Glycogen; 9007-92-5/Glucagon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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