Simulation of human thermoregulation during water immersion : Application to an aircraft cabin water-spray system

• Published in: Annals of biomedical engineering Vol. 25; no. 4; pp. 620 - 634
• Main Authors: WOLF, M. B, GARNER, R. P
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01-07-1997; Springer Nature B.V
• Subjects: Air exposure; Aircraft; Biological and medical sciences; Biothermics. Biomagnetism. Bioelectricity; Body Temperature Regulation - physiology; Cold Temperature; Evaporation; Fundamental and applied biological sciences. Psychology; Humans; Immersion - physiopathology; Models, Biological; Muscle, Skeletal - blood supply; Sensitivity and Specificity; Shivering - physiology; Simulation; Skin; Skin - blood supply; Space life sciences; Surface Properties; Temperature control; Tissues, organs and organisms biophysics; Vasoconstriction - physiology; Water; Heat transfer equation; Human; Temperature measurement; Cold; Heat production; Thermoregulation; Immersion; Mathematical model; Metabolism; Time variation
• ISSN: 0090-6964; 1573-9686
• DOI: 10.1007/BF02684840

A model was developed of transient changes in metabolic heat production and core temperature for humans subjected to cold conditions. It was modified to predict thermal effects of the upper parts of the body being sprayed with water from a system designed to reduce the smoke effects of an airplane fire. Temperature changes were computed at 25 body segments in response to water immersion, cold-air exposure, and windy conditions. Inputs to the temperature controller were: (a) temperature change signals from skin segments and (b) an integrated signal of the product of skin and head-core (hypothalamic) temperature changes. The controller stimulated changes in blood flow to skin and muscle and heat production by shivering. Two controller parameters were adjusted to obtain good predictions of temperature and heat-production experimental data in head-out, water-immersion (0 degree-28 degrees C) studies in humans. A water layer on the skin whose thickness decreased transiently due to evaporation was added to describe the effects of the water-spray system. Because the layer evaporated rapidly in a very cold and windy environment, its additional cooling effect over a 60-min exposure period was minimal. The largest additional decrease in rectal temperature due to the water layer was < 1 degree C, which was in normal conditions where total decreases were small.