Abstract
Interrelationships between ambient temperature, activity, and energy metabolism were explored in mice that had been selectively bred for high spontaneous wheel-running activity and their random-bred controls. Animals were exposed to three different ambient temperatures (10, 20 and 30 degrees C) and wheel-running activity and metabolic rate were measured simultaneously. Wheel-running activity was decreased at low ambient temperatures in all animals and was increased in selected animals compared to controls at 20 and 30 degrees C. Resting metabolic rate (RMR) and daily energy expenditure (DEE) decreased with increasing ambient temperature. RMR did not differ between control and selected mice, but mass-specific DEE was increased in selected mice. The cost of activity (measured as the slope of the relationship between metabolic rate and running speed) was similar at all ambient temperatures and in control and selected mice. Heat generated by running apparently did not substitute for heat necessary for thermoregulation. The overall estimate of running costs was 1.2 kJ/km for control mice and selected mice.
| Original language | English |
|---|---|
| Pages (from-to) | 109-118 |
| Number of pages | 10 |
| Journal | Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology |
| Volume | 177 |
| Issue number | 1 |
| Early online date | 24 Aug 2006 |
| DOIs | |
| Publication status | Published - Jan 2007 |
Keywords
- animals
- body mass index
- body temperature regulation
- eating
- energy metabolism
- linear models
- mice
- physical conditioning, animal
- temperature
- Ambient temperature
- Metabolism
- Thermoregulation
- Cold exposure
- Wheel-running activity