Effects of Environment on Metabolic Heat Production,
Abstract
Three different states must be distinguished to look for effects of environment on metabolism: changes in the basal state should reflect effects of adaptation; changes at rest in the environment in question would reflect direct thermal effects; and changes during work may reflect mechanical effects associated with the given environment. By definition, the basal metabolic rate in normal individuals should be independent of ambient environmental influences; contributions to about 40 kcal/sq m.hr (0.8 MET) BMR include about 0.1 MET from the central nervous system, about 0.2 MET from the cardiovascular and respiratory systems and about 0.5 MET from the remaining tissues comprising the lean body mass, at about 1.25 kcal/hr per kg of LBM, with muscle being a primary contributor. Fat is generally considered a negligible contributor to BMR, so changes in body fat may not alter BMR, but changes in muscle mass (i.e., increases as a result of increased work demands or decreases as a result of inactivity or inadequate nutrition) will; seasonal changes in BMR are frequently reported, but only occasionally attributed to altered physical activity or diet.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 19, 1978
- Accession Number
- ADA056625
Entities
People
- Ralph F. Goldman
Organizations
- United States Army Research Institute of Environmental Medicine