Effect of Age, Weight and Metabolic Rate on Endurance, Hyperthermia and Heatstroke Mortality,
Abstract
Since exercise performance is related to age, body weight, and metabolic efficiency, this investigation was designed to determine in rats the effects of these variables on endurance, thermoregulation and heatstroke mortality at a relatively mild environmental temperature. The results indicated that light rats (250g) are able to run (11m/min, 6 degree incline) longer (221min), accumulate less metabolic heat (.019 C/min) and thereby experience low heatstroke mortality (20%) despite a large amount of fluid loss (6.1%). This is in contrast to heavier and older rats (350g-500g) which demonstrated significantly reduced run times (108, 67 and 54 min), more rapid accumulations of metabolic heat (.04, .057 and .062 C/min) and much higher mortalities (50, 69 and 50%) despite smaller fluid losses (5.2, 3.7, or 4.2%). Although the mechanisms responsible for these varying thermoregulatory responses to exercise-induced exhaustion are not fully understood, the present data indicate that the rate of fluid loss, body composition, surface area to mass ratio and age are important variables.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1982
- Accession Number
- ADA145196
Entities
People
- M. J. Durkot
- R. Hubbard
- R. P. Francesconi
Organizations
- United States Army Research Institute of Environmental Medicine