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Exercise hyperthermia as a factor limiting physical performance - Temperature effect on muscle metabolismThe effect of trunk cooling on the muscle contents of ATP, ADP, AMP, creatine phosphate (CrP), and creatine, as well as of glycogen, some glycolytic intermediates, pyruvate, and lactate were assessed in 11 fasted dogs exercised at 20 C on treadmill to exhaustion. Without cooling, dogs were able to run 57 min, and their rectal (Tre) and muscle (Tm) temperatures increased to 41.8 and 43.0 C, respectively. Cooling with ice packs prolonged the ability to run by 45 percent, and resulted in lower Tre (by 1.1 C) and Tm (by 1.2 C). Depletion of muscle content of total high-energy phosphates (ATP + CrP) and glycogen, and increases in contents of AMP, pyruvate, and lactate were lower in cooled dogs than in non-cooled dogs. The muscle content of lactiate correlated positively with TM. These results indicate that hypothermia accelerates glycolysis, and shifts the equilibrium between high- and low-energy phosphates in favor of the latter. The adverse effect of hypothermia on muscle metabolism may be relevant to the limitation of endurance.
Document ID
Document Type
Reprint (Version printed in journal)
Kozlowski, S. (NASA Ames Research Center Moffett Field, CA, United States)
Brzezinska, Z. (NASA Ames Research Center Moffett Field, CA, United States)
Kruk, B. (NASA Ames Research Center Moffett Field, CA, United States)
Kaciuba-Uscilko, H. (NASA Ames Research Center Moffett Field, CA, United States)
Greenleaf, J. E. (NASA Ames Research Center Moffett Field, CA; Polish Academy of Sciences Medical Research Center, Warsaw, Poland)
Date Acquired
August 12, 2013
Publication Date
September 1, 1985
Publication Information
Publication: Journal of Applied Physiology
Volume: 59
ISSN: 0161-7567
Subject Category
Distribution Limits