Fig. 4. Effect of housing temperature on energy expenditure, respiratory exchange ratio, food intake, water intake, and activity level in mid-old DIO male mice.

Weight (a), fat free mass (b), and fat mass (c) at -9 day (the day before transfer to SABLE system). d Energy expenditure (EE, kcal/h). e Average energy expenditures (0–96 h) at different temperatures (kcal/24 h). f Respiratory exchange ratios (RER, VCO₂/VO₂). g Average RER (VCO₂/VO₂). h Cumulative food intake (g). i Average food intake (g/24 h). j Cumulative water intake (mL). k Average water intake (mL/24 h). l Cumulative activity level (m). m Average activity level (m/24 h). n weight (g) at day 23, o change in body weight; day 23 compared to day -9, p fat free mass at day 23, q change in fat free mass (g); day 23 compared to day -8, r fat mass (g) at day 23, s change in fat mass (g), day 23 compared to day -8. Statistical significance was tested by Oneway-ANOVA for repeated measurements followed by Tukey multiple comparison test. *P < 0.05, ***P < 0.001, ****P < 0.0001. Data are presented as means + SEM and dark phase (1800-0600h) is indicated with grey boxes. Dots in bar graphs indicate individual mice. Averages were calculated over the entire experimental period (0–96 h). n = 7.