Whole-body pre-cooling does not alter human muscle metabolism during sub-maximal exercise in the heat

Citation
J. Booth et al., Whole-body pre-cooling does not alter human muscle metabolism during sub-maximal exercise in the heat, EUR J A PHY, 84(6), 2001, pp. 587-590
Citations number
13
Categorie Soggetti
Physiology
Journal title
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY
ISSN journal
14396319 → ACNP
Volume
84
Issue
6
Year of publication
2001
Pages
587 - 590
Database
ISI
SICI code
1439-6319(200106)84:6<587:WPDNAH>2.0.ZU;2-G
Abstract
Muscle metabolism was investigated in seven men during two 35 min cycling t rials at 60% peak oxy gen uptake, at 35 degreesC and 50% relative humidity. On one occasion, exercise was preceded by whole-body cooling achieved by i mmersion in water during a reduction in temperature from 29 to 24 degreesC, and, for the other trial, by immersion in water at a thermoneutral tempera ture (control, 34.8 degreesC). Pre-cooling did not alter oxygen uptake duri ng exercise (P > 0.05), whilst the change in cardiac frequency and body mas s both tended to be lower following pre-cooling (0.05 < P < 0.10). When ave raged over the exercise period, muscle and oesophageal temperatures after p re-cooling were reduced by 1.5 and 0.6 degreesC respectively, compared with control (P<0.05). Pre-cooling had a limited effect on muscle metabolism, w ith no differences between the two conditions in muscle glycogen, triglycer ide, adenosine triphosphate, creatine phosphate, creatine or lactate conten ts at rest, or following exercise. These data indicate that whole-body pre- cooling does not alter muscle metabolism during submaximal exercise in the heat. It is more likely that thermoregulatory and cardiovascular strain are reduced, through lower muscle and core temperatures.