Table 3.

Sleep variables by gender (mean ± s.d., *p < 0.05).

	Total (n = 101)	Boys (n = 44)	Girls (n = 57)	p-value
Nighttime sleep variables
Bed time	20:58 ± 0:42	20:46 ± 0:38	21:07 ± 0:42	0.436
Sleep onset time	21:28 ± 0:43	21:18 ± 0:39	21:35 ± 0:45	0.200
Wake time	6:58 ± 0:40	6:57 ± 0:39	7:00 ± 0:41	0.532
Daily variation in sleep onset time	33.5 ± 18.7	35.4 ± 19.8	32.1 ± 17.9	0.741
Daily variation in wake time	33.0 ± 15.7	35.1 ± 17.9	31.3 ± 13.7	0.048*
Sleep latency (min)	29.7 ± 14.7	33.0 ± 15.7	27.1 ± 13.3	0.317
Nighttime sleep duration (h)	9.4 ± 0.6	9.5 ± 0.6	9.4 ± 0.6	0.842
Total sleep duration (h)	11.3 ± 0.6	11.4 ± 0.6	11.3 ± 0.6	0.608
Sleep efficiency (%)	85.7 ± 9.0	83.7 ± 11.0	87.2 ± 6.9	0.035*
WASO (wake after sleep onset)(min)	82.6 ± 51.8	94.0 ± 61.4	73.8 ± 41.4	0.056
Nighttime activity (counts/min)	26.4 ± 10.2	29.0 ± 12.3	24.3 ± 7.8	0.111
Daytime sleep variables
Daytime activity (counts/min)	239 ± 19.4	240 ± 22.8	239 ± 16.6	0.183
Nap duration (h)	2.0 ± 0.4	2.0 ± 0.4	1.9 ± 0.5	0.068
Nap onset time	12:37 ± 1:04	12:23 ± 0:48	12:48 ± 1:12	0.017*
Nap end time	15:00 ± 0:52	14:50 ± 0:42	15:08 ± 0:57	0.086