Fig. 5: DI drastically decreases activity, dampens circadian variations of heart rate and blood pressure, and lowers core body temperature.

a Accelerometry-derived daily physical activity counts estimated by magnitude of vector during the day and the night from the wrist (left) (n = 16), and the ankle (right) (n = 17). b Continuous recording of heart rate and blood pressure averaged over 15 min. c Mean heart rate and blood pressure for day (09:30−23:00) and night (23:00−07:00), and the difference between them (right panel) (n = 18). d Continuous recording of core body temperature averaged over 15 min. The baseline curve represents the mean of B3 to B1, During DI from D1 to D5, and Recovery from R0 to R1 (n = 6). e Core body temperature for the day (07:00−23:00) and night (23:00−07:00) (left) and mesor (right) (n = 6). Bars represent mean ± s.e.m. Box plots indicate minimum, 25th percentile, median, 75th percentile, and maximum values. a, e Two-way RM ANOVA with post-hoc Bonferroni multiple comparison. Asterisks indicate a significant difference (P < 0.05) compared with B1, and [#] indicates a significant difference compared with night. Global ANOVA results: wrist activity immersion effect P < 0.001 and day/night effect P < 0.001, Ankle activity immersion effect P < 0.001 and day/night effect P < 0.001. c One-way RM ANOVA with post hoc Bonferroni multiple comparison compared with B3. Global ANOVA results: heart rate day P < 0.001 and night P = 0.089 and day-night difference P < 0.001, systolic BP day P = 0.040 and night P < 0.001 and day-night difference P < 0.001, diastolic BP day P < 0.001 and night P < 0.001 and day-night difference P < 0.001. e Global ANOVA results: CBT° immersion effect P = 0.04 and day/night effect P < 0.001, Mesor (24 h) P = 0.03. BP blood pressure.