Housing temperature alters exercise training adaptations in mice

Exercise training is a powerful means to combat metabolic pathologies. Mice are extensively used to describe exercise benefits at the molecular level, but ambient housing temperatures confound translation to humans. Thermoneutral housing is a strategy to make mice more metabolically similar to humans but its effects on exercise adaptations is unknown. Using voluntary wheel running, we show that thermoneutral housing blunted exercise-induced improvements in glucose tolerance and insulin action in muscle and adipose tissue. Moreover, thermoneutrality reduced the training effects on energy expenditure, body composition, muscle and adipose tissue protein expressions, and gut microbiota. The majority of these thermoneutral-dependent training adaptations could not be ascribed to a lower voluntary running volume. Thus, we conclude that organismal and molecular adaptations to exercise training in mice critically depend upon housing temperature. Our findings underscore the importance of housing temperature as a crucial parameter in the design and interpretation of murine exercise studies.