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Title

Conductive and convective heat flows of exercising humans in cold water

Authors
Veicsteinas, Arsenio
Rennie, D. W.
Published in Journal of Applied Physiology: Respiratory, Environmental & Exercise Physiology. 1989, vol. 67, no. 6, p. 2473-2480
Abstract The apparent conductance (Kss, in W.m-2.degrees C-1) of a given region of superficial shell (on the thigh, fat + skin) was determined on four nonsweating and nonshivering subjects, resting and exercising (200 W) in water [water temperature (Tw) 22-23 degrees C] Kss = Hss/(Tsf-Tsk) where Hss is the skin-to-water heat flow directly measured by heat flow transducers and Tsf and Tsk are the temperatures of the subcutaneous fat at a known depth below the skin surface and of the skin surface, respectively. The convective heat flow (qc) through the superficial shell was then estimated as qc = (Tsf - Tsk).(Kss - Kss,min), assuming that at rest Kss was minimal (Kss,min) and resting qc = 0. The duration of immersion was set to allow rectal temperature (Tre) to reach approximately 37 degrees C at the end of rest and approximately 38 degrees C at the end of exercise. Except at the highest Tw used, Kss at the start of exercise was always Kss,min and averaged 51 W.m-2.degrees C-1 (range 33-57 W.m-2.degrees C-1) across subjects, and qc was zero. At the end of exercise at the highest Tw used for each subject, Kss averaged 97 W.m-2.degrees C-1 (range 77-108 W.m-2.degrees C-1) and qc averaged 53% (range 48-61%) of Hss (mean Hss = 233 W.m-2).
Keywords AdultBody Temperature Regulation/ physiologyCold TemperatureExercise/ physiologyHumansImmersion/ physiopathologyMaleThermodynamics
Stable URL http://archive-ouverte.unige.ch/unige:10269
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Other version: http://jap.physiology.org/cgi/reprint/67/6/2473.pdf
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PMID: 2606856
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