A Linearized, Time Dependent Model of the Heat Transfer and Thermoregulatory Responses Occurring upon Immersion in Cold Water
Abstract
Twenty males subjects (17 to 28 yrs of age) exhibiting a range of body weights (60 less than or = BW less than or = 95 Kg) and body fat (7% less than or = BF less than or = 23%) underwent total immersion while at rest in water between 36 C and 20 C. Their metabolic heat production, which were measured as functions of time and water temperature, were converted to explicit linear functions of core (T sub re) and skin (T sub s) temperatures for each individual immersion. These were used to define planes of thermogenic activity which allowed the comparison of the onset and magnitude of shivering between individuals of any morphological group. These thermogenic planes show too much steeper slope with respect to the T sub s axis for small, thin men than for heavy, fat men, while men of average weight and fat composition exhibit an intermediate slope. Small, lean men also appear to exhibit thermogenic planes having steeper slopes with respect to the T sub re axis than do average and heavy men. Analysis showed that both metabolic and cardiovascular compensation occurs at higher bath temperatures for small, lean men than heavy fat men. It also showed that body size is more important than body fat content alone in determining maximal total internal insulation. The analysis showed that clothing can lower core temperature rather than elevate it, particularly for some heavy subjects by increasing internal conductances and lowering heat production. This occurs in the face of a net increase in external insulation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1982
- Accession Number
- ADA124972
Entities
People
- Louis Strong
- Ralph F. Goldman
Organizations
- United States Army Research Institute of Environmental Medicine