Biomaterial Database

Respiratory heat loss during work at various ambient temperatures. 1990

J B Cain, and S D Livingstone, and R W Nolan, and A A Keefe

Defence Research Establishment Ottawa, Environmental Protection Section, Ontario, Canada.

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 -40 degrees C and 20 degrees C in order to calculate respiratory heat loss. 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 between 25 and 30% of the resting metabolic and between 15 and 20% of the working metabolic rate.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008660	Metabolism	The chemical reactions in living organisms by which energy is provided for vital processes and activities and new material is assimilated.	Anabolism,Catabolism,Metabolic Concepts,Metabolic Phenomena,Metabolic Processes,Metabolic Phenomenon,Metabolic Process,Metabolism Concepts,Metabolism Phenomena,Process, Metabolic,Processes, Metabolic,Concept, Metabolic,Concept, Metabolism,Concepts, Metabolic,Concepts, Metabolism,Metabolic Concept,Metabolism Concept,Phenomena, Metabolic,Phenomena, Metabolism,Phenomenon, Metabolic
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D001833	Body Temperature Regulation	The processes of heating and cooling that an organism uses to control its temperature.	Heat Loss,Thermoregulation,Regulation, Body Temperature,Temperature Regulation, Body,Body Temperature Regulations,Heat Losses,Loss, Heat,Losses, Heat,Regulations, Body Temperature,Temperature Regulations, Body,Thermoregulations
D005082	Physical Exertion	Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.	Physical Effort,Effort, Physical,Efforts, Physical,Exertion, Physical,Exertions, Physical,Physical Efforts,Physical Exertions
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures