Journal of Applied Physiology, Vol 40, Issue 5 668-672, Copyright © 1976 by American Physiological Society
Effect of neck versus chest cooling on responses to work in heat
E. Shvartz
Six young men performed bench-stepping at a load of 40 W, once at room
temperature of 23 degrees C and 3 times in heat (39.5 degrees C db, 30.3
degrees C wb). Two of the heat exposures included cooling of either the
neck or chest by circulating cool water having an inlet temperature of 8.3
degrees C. The heat exchanges for the neck and chest were of equal size and
they consisted of PVC tubes, having a total length of 3m each, which
covered 2.2% of the body surface area. Heat exchange between the tubing
assemblies and the environment was prevented by proper insulation. As
compared with no cooling in heat, each method of cooling resulted in no
change in heart rate, a decrease of 0.5 degrees C in rectal temperature,
small and insignificant decreases in skin temperature and 16-22% decreases
in sweat rates. Heat removed from the neck and chest equalled 63.1 and61.9
W-m-2, respectively. This large heat removal and the substantial decreases
in rectal temperature and sweat rate as a result of cooling 2.2% of the
body surface area were explained in terms of the powerful effect of
conductive cooling and the particular regions which were cooled.
