| Abstrakt: |
It has previously been demonstrated that metabolic heat production (M˙) during cold exposure at rest was related to maximal oxygen uptake (O2max). Consequently, an increase in O2max could allow an increase M˙ in the cold. The aim of the present study was therefore to test this hypothesis. Eight male volunteers undertook interval training (periods of 25% V˙O2max of 30-s duration and 110% V˙O2max of 60-s duration until exhaustion, five times a week over 8 weeks) to increase V˙O2max. Both before and after this physical training, they were subjected to a 10∘, 5∘ and 1∘C 2-h cold air test in a climatic chamber. During the cold exposure, rectal temperature ( Tre), tympanic temperature ( Tty), mean skin temperature ( ) and M˙ were measured as well as the time to onset of shivering ( t) and body temperatures ( ) at t. The results showed that physical training involved an increase in O2max (14%–15%, P < 0.05). During the cold exposure, Tre was higher after training both at 10∘,5∘ and 1∘C ( P < 0.05) whereas were not significantly changed. However, an increase in the sensitivity of the thermoregulatory system was attested by a decreased t at higher These slight physiological changes found after training were not related to the increases in V˙O2max. In conclusion, this study demonstrated that interval training induced slight thermoregulatory changes unrelated to changes in V˙O2max and it suggested that M˙ during cold exposure could be related mainly to the level of V˙O2max observed before training, since increases in V˙O2max did not modify M˙. [ABSTRACT FROM AUTHOR] |
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