How stable is your vivarium's temperature? Fluctuations in vivarium temperature significantly impact metabolism and behavior impeding scientific reproducibility

Objectives
The purpose of this investigation was to examine the variability in vivarium temperature and the impact that this has on metabolic and behavioral outcomes in mice.
Methods
Daily vivarium temperature was monitored every day for a two-year period. Behavioral and metabolic phenotyping were assessed in male and female C57BL/6 (n = 71/sex) mice over the course of 2 years.
Results
Vivarium temperature was found to fluctuate on a monthly, daily, and even an hourly basis of approximately ±5ºC. A 5ºC change in temperature was found to result in daily changes in total energy expenditure (35% and 27%), resting energy expenditure (39% for both sexes), movement (51% and 37%), food consumption (35% and 29%), and sleep duration (15% and 13%) for female and male mice, respectively.
Conclusions
Fluctuations in vivarium temperature can dramatically impact metabolic and behavioral outcomes, which impedes scientific reproducibility. This awareness and the guidelines we propose in this publication will hopefully help to enhance the reproducibility of pre-clinical animal research.