Table 5.

Linear relationships between physical activity and night-to-night variations in sleep parameters^a

	All (N=247)			Boys (N=103)			Girls (N=144)
	β	SE	pb	B	SE	pb	β	SE	pb
Sleep duration
SD_Total sleep time (min)
Unadjusted	−0.008	0.005	0.13	−0.006	0.010	0.58	−0.008	0.005	0.15
Adjustedc	−0.003	0.005	0.56	0.0038	0.010	0.71	−0.005	0.005	0.31
SD_Total rest time (min)
Unadjusted	−0.012	0.006	0.04	−0.012	0.011	0.27	−0.010	0.006	0.10
Adjustedc	−0.007	0.006	0.24	−0.0015	0.011	0.89	−0.008	0.006	0.22
Sleep quality
SD_Sleep efficiency (%)
Unadjusted	2.2x10−4	2.2x10−4	0.32	2.3x10−4	3.7x10−4	0.54	5.5x10−4	2.6x10−4	0.04
Adjustedc	1.8x10−4	2.2x10−4	0.42	−2.5x10−4	4.0x10−4	0.53	5.1x10−4	2.7x10−4	0.06
SD_Sleep onset latency (min)
Unadjusted	1.6x10−5	9.5x10−5	0.87	1.7x10−4	1.4x10−4	0.22	9.0x10−5	1.3x10−4	0.48
Adjustedc	3.9x10−5	9.8x10−5	0.69	2.8x10−4	1.5x10−4	0.06	−8.5x10−5	1.3x10−4	0.53
SD_Number of awakenings (n)
Unadjusted	−1.4x10−3	3.3x10−4	<0.001	−0.002	5.9x10−4	0.003	−0.001	3.8x10−4	0.006
Adjustedc	−1.4x10−3	3.5x10−4	<0.001	−0.002	6.3x10−4	0.015	−0.001	3.9x10−4	0.006
Sleep timing
SD_Bedtime (min)
Unadjusted	4.3x10−4	0.005	0.94	0.007	0.012	0.55	−0.001	0.004	0.80
Adjustedc	0.006	0.005	0.30	0.019	0.012	0.11	0.001	0.004	0.82
SD_Rise time (min)
Unadjusted	−0.017	0.005	0.002	−0.015	0.010	0.14	−0.016	0.006	0.008
Adjustedc	−0.014	0.005	0.013	−0.010	0.010	0.32	−0.015	0.006	0.016

SD = standard deviation; β = unstandardized regression coefficient; SE = standard error; min = minutes; n/N = number.

^aPhysical activity (counts/min/day) and night-to-night variations (as SDs) in sleep parameters for the entire week.

^bp-value < 0.05 (bolded) was considered to show statistically significant relationship between physical activity and outcome variables.

^cAdjusted for screen time, body fat percentage and parental education.