Circadian phase advances in children during camping life according to the natural light-dark cycle

Table 1 Sleep habits and circadian phase

	Earlier wake time (EW) condition (n = 16)				Synchronized wake time (SW) condition (n = 15)
[h:m]	PreCamp (Mean ± SD)	Camp (Mean ± SD)	t value	p value	PreCamp (Mean ± SD)	Camp (Mean ± SD)	t value	p value
Bedtime	21:26 ± 0:54^†	19:48 ± 0:15	7.03	< 0.0001	22:05 ± 0:52^†	19:56 ± 0:12	10.56	< 0.0001
Wake time	6:06 ± 0:59	4:08 ± 0:17^‡	8.92	< 0.0001	6:41 ± 0:58	4:35 ± 0:16^‡	8.85	< 0.0001
Mid-sleep point	25:46 ± 0:51	23:58 ± 0:09^‡	8.90	< 0.0001	26:23 ± 0:52	24:12 ± 0:13^‡	11.21	< 0.0001
Sleep duration	8:40 ± 0:46	8:20 ± 0:25^†	1.65	0.12	8:36 ± 0:36	8:45 ± 0:34^†	0.80	0.43
DLMO	20:11 ± 0:49^†	18:09 ± 0:33^‡	9.74	< 0.0001	20:50 ± 0:45^†	18:43 ± 0:20^‡	10.38	< 0.0001

Each index was compared between PreCamp and Camp using the paired t test. Data for sleep habits (bedtime, wake time, mid-sleep point, and sleep duration) were averaged data for a period of 2 weeks before the camping program and averaged data from the day of the first circadian phase (DLMO) assessment (first day of the camping program in both conditions) to the day of the second DLMO assessment (11th day in the EW condition and 14th day in the SW condition)
DLMO Dim light melatonin onset

ISSN: 1880-6805