Calorimetric analysis of the effect of drinking saline solution on whole-body sweating. I. An attempt to measure average body temperature
Snellen, J.W.; Mitchell, D.; Busansky, M.
Pflugers Archiv European Journal of Physiology 331(2): 124-133
1972
ISSN/ISBN: 0031-6768 PMID: 5063290 Document Number: 52752
A healthy young man lay in a calorimeter at air temperature 36.5 degrees and dew point 11 degrees C; in the first 2 h he reached heat equilibrium and then he drank 1 litre of a flavoured 0.9% NaCl solution at a controlled temperature. Heat exchange was recorded for another hour and equilibrium was regained in the last 30 min. The test was repeated 15 times with the saline at different temperatures. The response to drinking was the difference, in Watt-min, between net heat loss after drinking and that during energy equilibrium. A linear relation with unit slope was found between the response to drinking and the heat content of the fluid drunk; the temperature of the fluid at zero response was 31.0 degrees C. The experiment demonstrates that the human thermoregulatory mechanism operates on a Joule-per-Joule basis, and that drinking provokes a sweating response in addition to the energy demand.