Summary:The TSE PhenoMaster/LabMaster Metabolic Cage system is used to measure indirect calorimetry, food/water intake, energy expenditure, and physical activity in individually housed awake mice. The experiment noninvasively measures VO² consumption and VCO² production rates in individual mice using metabolic chambers and calculates the respiratory exchange ratio (respiratory quotient) to reflect energy expenditure. Metabolic cage measurement is conducted continuously for 72 hours (3 days) to account for acclimation of mice housed in home cages during the study. With our high-speed Siemens O²/CO² sensing unit, indirect calorimetry measurements may be performed at a 20-min interval for a full 12-cage study.