Prior exercise training improves cold tolerance independent of indices associated with non-shivering thermogenesis
The purpose of this thesis was to determine whether previous exercise training via voluntary wheel running (VWR) would improve cold tolerance by protecting against cold-induced reductions in rectal temperature. We hypothesized that this would be associated with an exercise-induced increase in white adipose tissue browning, which would contribute in an additive manner to cold-induced nonshivering thermogenesis. To examine this, male C57BL6 mice remained sedentary or were given free access to a wheel for 12 days. Mice were then kept at room temperature (25oC) or subjected to cold stress (4oC) for a period of 48 hours. The primary findings were two-fold; 1) prior exercise via VWR protects against cold-induced weight loss, through a mechanism involving increases in food intake and 2) prior exercise via VWR protects against cold-induced reductions in rectal temperature, however this is likely not associated with UCP-1-dependent nonshivering thermogenesis. Rather, the capacity for shivering thermogenesis may be enhanced.