Accession Number:

ADA100582

Title:

Thermal Constraints in Diving.

Descriptive Note:

Corporate Author:

UNDERSEA MEDICAL SOCIETY INC BETHESDA MD

Personal Author(s):

Report Date:

1981-04-01

Pagination or Media Count:

441.0

Abstract:

Despite considerable investigation since the 1974 UMS Workshop, the relationship between body heat loss and core temperature change in cold water exposure has not been definitively elucidated. The relationship appears to be dependent on the rate of cooling in that loss of a given amount of heat at a rapid rate causes a greater drop in rectal temperature and more shivering as compared to loss of the same heat over a longer time which results in little rectal temperature drop, no shivering and only minor complaints of mild cold stress. Although the performance decrement associated with each type of exposure remains to be determined, there has not yet been any explanation of this documented effect of rate of cooling. The effect is pertinent not only to use of the rectal temperature but is applicable to various core temperature measurement sites. New experiments were described that documented the relationship between individual body size and fatness characteristics and cooling rate. For the same body mass and height, variation of body fat was shown to cause a large variation in rectal temperature decrease and heat loss the fatter the individual, the less the change. For the same body fat percentage, variation of body mass and height has a large effect in rectal temperature and heat loss the larger the individual, the less the change. People of identical skinfold thickness and sex have enormous differences in rates of cooling.

Subject Categories:

  • Stress Physiology
  • Military Operations, Strategy and Tactics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE