Table 1.

Period estimates (mean ± SD) for three of the FD T cycles

	T = 20 h	T = 28 h	T = 42.85 h
Temperature	24.12 ± 0.15	24.16 ± 0.21	24.15 ± 0.17
	(n = 26)	(n = 114)	(n = 16)
Melatonin	24.12 ± 0.14	24.15 ± 0.22	24.17 ± 0.15
	(n = 26)	(n = 89)	(n = 14)

Average (±SD) intrinsic circadian period estimates derived from core body temperature and melatonin data of participants studied on three different FD T cycles. One participant studied on a T cycle of 11 h is not included in this table. Intrinsic circadian period data derived from core body temperature and melatonin were similar within and between each T-cycle group.