Author/Editor		Mittleman, KD; Mekjavić, IB
Title		Contribution of core cooling rate to shivering thermogenesis during cold water immersion
Type		članek
Source		Aviat Space Environ Med
Vol. and No.		Letnik 62, št. 9 Pt 1
Publication year		1991
Volume		str. 842-8
Language		eng
Abstract		The contribution of core cooling rate to the thermogenic response in humans, for a similar combination of core and peripheral thermal inputs, was studied. Seven male subjects were immersed in 15 degrees C water on two occasions. Trial A was conducted without any intervention. During Trial B extremity blood flow was occluded for 10 min to allow limb blood to cool toward the temperature of the surrounding tissues. Upon release of cuff pressure the cooled, trapped blood returned to the core region instigating a decrease in esophageal temperature (Tes), with a concomitant increase in heat production (H). The slope of the Tes-H relationship during the dynamic post-occlusion phase was defined as central thermosensitivity (beta B). The slope of the Tes-H relationship during Trial A (beta A), evaluated over a similar range of core temperatures but over a longer time period, was compared with beta B to determine the influence of core cooling rate on the thermogenic response. The rate of core cooling (Tes) increased from -0.05 +/- 0.01 degrees C.min-1 in Trial A to -0.23 +/- 0.02 degrees C.min-1 with cuff occlusion-release in Trial B, resulting in a significant increase in beta B when compared to beta A (-2.99 +/- 0.36 vs. -1.90 +/- 0.24 W.kg-1.degrees C-1). Results of this study indicate that during cold water immersion: 1) dynamic core temperature significantly contributes to the magnitude of metabolic heat production; and 2) individual differences exist in central thermosensitivity.
Descriptors		COLD EXTREMITIES IMMERSION SHIVERING ADULT BODY TEMPERATURE REGULATION REGIONAL BLOOD FLOW