Control of skin blood flow in the neutral zone of human body
temperature regulation.
Savage, Margaret V., and George L. Brengelmann.
Departments of Physiology and Biophysics, University of Washington,
Seattle, WA, 98195 and School of Kinesiology, Simon Fraser
University, Burnaby, B.C., Canada
APStracts 2:0540A, 1995.
In humans, matching of heat loss and heat production in the
"neutral" zone, defined operationally in terms of a range of
skin temperatures (Tsk), is accomplished by regulation of skin blood
flow (SkBF). Our studies were designed to reveal the characteristics
of control of SkBF (from measurements of forearm blood flow, FBF) in
this zone. We controlled the temperature of water sprayed on most of
the body of supine men and women at 33 or 35 degrees C in a square
wave pattern (15 min at each temperature) or a step pattern (60 min
at 33 degrees C separating short periods at 35 degrees C). FBF
followed Tsk (0.5 ml x min-1 x 100ml-1 per degrees C). Tes changed
approximately 0.11 degrees C with each 2 degrees C Tsk change,
falling with Tsk increase and vice versa. Little influence on FBF,
less than 0.1 ml x min-1 x 100ml-1 per degrees C, was observed when
only the forearm was sprayed with 33 and 35 degrees C water. We
conclude that SkBF control in the 33-35 degrees C range of Tsk is
dominated by the feedforward reflex influence of Tsk on SkBF. The
reflex response overcompensates for the effect of Tsk on thermal
balance in the neutral zone so that equilibrium Tc has an inverse
relationship to Tsk.
Received 13 April 1995; accepted in final form 27 November 1995.
APS Manuscript Number A408-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 12 December 95