MEASUREMENT OF RESPIRATORY AIR TEMPERATURES AND CALCULATION OF RESPIRATORY HEAT LOSS WHEN WORKING AT VARIOUS AMBIENT TEMPERATURES

Authors
  1. Cain, J.B.
  2. Livingstone, S.D.
  3. Nolan, R.W.
  4. Keefe, A.A.
Corporate Authors
Defence Research Establishment Ottawa, Ottawa ONT (CAN)
Abstract
The purpose of this investigation was to establish the temperature and humidity of the expired air of subjects working at various metabolic rates at ambient temperatures between -40C and 20C in order to calculate the heat loss from the body due to respiration. Measurements of the respired air temperature and water vapour content were made for five subjects while they either stood or walked on a treadmill. The results indicated that the maximum respired air temperature varied slightly with the ambient air temperature but changes in metabolic rate, respiration rate and breathing frequency had no apparent effect on the expired air temperature under the conditions studied. The relative humidity of the respired air was found to be close to saturation in the extreme-cold environments. Heat loss due to respiration was calculated and the influence of various physiological and environmental variables on the respiratory heat loss is discussed.
Report Number
DREO-1004 —
Date of publication
15 Mar 1989
Number of Pages
23
DSTKIM No
89-02818
CANDIS No
60721
Format(s):
Hardcopy;Originator's fiche received by DSIS

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