Effect of water temperature on cooling efficiency during hyperthermia in humans

J Appl Physiol (1985). 2003 Apr;94(4):1317-23. doi: 10.1152/japplphysiol.00541.2002. Epub 2002 Nov 27.


We evaluated the cooling rate of hyperthermic subjects, as measured by rectal temperature (T(re)), during immersion in a range of water temperatures. On 4 separate days, seven subjects (4 men, 3 women) exercised at 65% maximal oxygen consumption at an ambient temperature of 39 degrees C until T(re) increased to 40 degrees C (45.4 +/- 4.1 min). After exercise, the subjects were immersed in a circulated water bath controlled at 2, 8, 14, or 20 degrees C until T(re) returned to 37.5 degrees C. No difference in cooling rate was observed between the immersions at 8, 14, and 20 degrees C despite the differences in the skin surface-to-water temperature gradient, possibly because of the presence of shivering at 8 and 14 degrees C. Compared with the other conditions, however, the rate of cooling (0.35 +/- 0.14 degrees C/min) was significantly greater during the 2 degrees C water immersion, in which shivering was seldom observed. This rate was almost twice as much as the other conditions (P < 0.05). Our results suggest that 2 degrees C water is the most effective immersion treatment for exercise-induced hyperthermia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Temperature*
  • Cold Temperature*
  • Exercise
  • Female
  • Fever / etiology
  • Fever / physiopathology*
  • Fever / therapy*
  • Humans
  • Immersion*
  • Male
  • Rectum / physiopathology
  • Temperature*
  • Water*


  • Water