Table 2.

Nadir of body temperature, RQ and energy expenditure during sleep in men and women.

	Men	Women	P-value
RQa	3.36 ± 0.19	1.95 ± 0.30	0.0001
Energy expenditurea	3.72 ± 0.22	4.80 ± 0.33	0.0076
Core body temperatureb	3.48 ± 0.33	1.98 ± 0.49	0.0115

Time of the nadir (5-min period of the lowest value) was shown as time after bedtime in hours for RQ, energy expenditure and body temperature. Bedtime of each experiment was 23:00^18–22 or at subjects’ habitual bedtime (23:00–24:30)^8,23–25. In studies with an 8-h sleep opportunity, data of the first 7 h was included for statistical analysis^8,23–25. The nadir of the RQ (P = 0.608), energy expenditure (P = 0.858) and body temperature (P = 0.310) during sleep in women was not related to their menstrual cycle.

^aMean age of the men (n = 79, 24.5 ± 0.5 years) and women (n = 36, 23.4 ± 0.3 years) were comparable (P = 0.169)^8,18–25.

^bMean age of the men (n = 30, 23.8 ± 0.3 years) and women (n = 18, 23.7 ± 0.5 years) were comparable (P = 0.750)^21–24.