The temporal and bi-directional relationship between physical activity and sleep in ambulatory children with cerebral palsy

Figures & data

Table 1. Participants characteristics.

N = 51
		Mean	SD
		6.8	2.6
Age (years)		N	%
Boys		29	56.9
Girls		22	43.1
GMFCS 1		30	58.8
GMFCS 2		12	23.5
GMFCS 3		9	17.6
General sleep questionnaire
Reported sleep problems	Yes	11	21.6
	No	38	74.5
	N/A	2	3.9
Reported use of sleep medication or -aids	Yes	3	5.9
	No	46	90.2
	N/A	2	3.9
Generally satisfied with child’s sleep	Never	2	3.9
	Sometimes	7	13.7
	Often	40	78.4
	N/A	2	3.9

GMFCS: gross motor function classification system; N/A: not answered.

Table 2. Means of physical activity, sedentary time, and sleep measures.

	All		Week		Weekend
N = 51	Mean (SD)	Range	Mean (SD)	Range	Mean (SD)	Range	p-value
SED (min/12h day)	439.6 (70.0)	216.9–673.4	440.8 (70.4)	258.5–668.7	432.7 (83.8)	216.9–673.4	0.686
LPA (min/12h day)	241.9 (56.8)	46.4–441.4	241.9 (58.0)	49.3–409.8	241.9 (68.6)	46.4–441.4	1.000
MVPA (min/12h day)	38.4 (18.9)	0.25–100.6	37.3 (18.9)	0.25–97.4	40.5 (23.8)	0.26–100.62	0.173
VM (counts/min)	987.7 (324.3)	104.1–1995.2	979.4 (328.4)	104.1–1762.3	1001.2 (376.8)	110.0–1995.2	0.499
V (counts/min)	455.6 (165.4)	41.7–1204.0	444.8 (167.4)	44.7–1204	476.9 (201.2)	41.7–1126.7	0.096
SE (%)	82.4 (5.9)	48.4–97.7	82.5 (6.0)	48.4–97.7	82.2 (7.1)	61.6–96.6	0.554
SOL (min)	19.3 (12.9)	0–114	20.4 (14.3)	0–114	17.1 (14.3)	0–98	0.066
TBT (min)	659.2 (46.0)	465–849	657.9 (44.5)	530–791	660.9 (63.9)	456-849	0.638
TST (min)	542.6 (50.4)	295–742	542.4 (50.3)	295–727	541.9 (62.6)	385-742	0.926

SED: sedentary time; LPA: light physical activity; MVPA: moderate-to-vigorous physical activity; VM: vector magnitude; V: vertical axis, SE: sleep efficiency, SOL: sleep onset latency; TBT: total in bed time, TST: total sleep time. p-value represents the significance level for the difference between week and weekend.

Table 3. Associations between physical activity the preceding day and sleep the following night.

PA/SED → Sleep
			ALL (N = 51)		Week (N = 51)		Weekend (N = 51)
			β (95% CI)	p-value	β (95% CI)	p-value	β (95% CI)	p-value
SED	>	SE	0.015 (0.003, 0.027)	0.014	0.016 (0.002, 0.030)	0.025	0.011 (−0.012, 0.033)	0.349
		SOL	0.006 (−0.023, 0.034)	0.694	0.002 (−0.034, 0.037)	0.915	−0.020 (−0.060, 0.021)	0.333
		TBT	0.014 (−0.056, 0.085)	0.689	0.013 (−0.060, 0.087)	0.718	0.035 (−0.121, 0.192)	0.654
		TST	0.134 (0.044, 0.223)	0.004	0.119 (0.015, 0.223)	0.025	0.183 (0.009, 0.357)	0.040
LPA	>	SE	−0.016 (−0.030, −0.001)	0.041	−0.017 (−0.034, 0.001)	0.063	−0.012 (−0.042, 0.017)	0.409
		SOL	−0.005 (−0.042, 0.031)	0.772	−0.005 (−0.049, 0.039)	0.822	0.027 (−0.027, 0.080)	0.327
		TBT	−0.035 (−0.124, 0.055)	0.449	−0.032 (−0.124, 0.060)	0.498	−0.068 (−0.277, 0.141)	0.517
		TST	−0.157 (−0.271, −0.043)	0.007	−0.128 (−0.259, 0.004)	0.056	−0.274 (−0.500, −0.048)	0.018
MVPA	>	SE	−0.049 (−0.085, −0.012)	0.010	−0.055 (−0.099, −0.010)	0.017	−0.026 (−0.094, 0.042)	0.441
		SOL	−0.022 (−0.107, 0.064)	0.615	0.015 (−0.098, 0.127)	0.796	0.040 (−0.071, 0.151)	0.468
		TBT	0.069 (−0.147, 0.285)	0.531	0.065 (−0.167, 0.296)	0.583	0.016 (−0.441, 0.472)	0.946
		TST	−0.341 (−0.619, −0.063)	0.016	−0.384 (−0.713, −0.056)	0.022	−0.179 (−0.632, 0.274)	0.434
VMCPM	>	SE	−0.004 (−0.006, −0.001)	0.002	−0.005 (−0.008, −0.002)	0.002	−0.002 (−0.006, 0.003)	0.487
		SOL	0.000 (−0.006, 0.006)	0.900	0.002 (−0.005, 0.010)	0.547	0.003 (−0.005, 0.011)	0.443
		TBT	−0.005 (−0.019, 0.010)	0.526	−0.001 (−0.017, 0.014)	0.849	−0.014 (−0.047, 0.019)	0.411
		TST	−0.032 (−0.050, −0.013)	0.001	−0.034 (−0.055, −0.012)	0.002	−0.025 (−0.060, 0.010)	0.156
VCPM	>	SE	−0.006 (−0.010, −0.002)	0.007	−0.007 (−0.012, −0.002)	0.007	−0.002 (−0.010, 0.007)	0.645
		SOL	0.000 (−0.010, 0.010)	0.986	0.006 (−0.007, 0.018)	0.372	0.005 (−0.007, 0.018)	0.384
		TBT	0.003 (−0.022, 0.028)	0.795	0.006 (-−.020, 0.032)	0.667	−0.013 (−0.074, 0.048)	0.647
		TST	−0.042 (−0.074, −0.010)	0.011	−0.045 (−0.083, −0.008)	0.018	−0.025 (−0.080, 0.030)	0.368

SE: sleep efficiency; SOL: sleep onset latency, TBT: Total in Bed Time; TST: Total Sleep Time, SED = sedentary time; LPA = light physical activity, MVPA: moderate-to-vigorous activity, VMCPM: vector magnitude average counts per minute, VCPM: vertical axis average counts per minute. SED, LPA & MVPA are standardized to 12 h per day. Significant p-values are highlighted in bold.

All models were adjusted for age, sex, GMFCS-level.

Table 4. Associations between sleep the preceding night and physical activity the following day.

Sleep → PA/SED
			All (N = 51)		Week (N = 51)		Weekend (N = 51)
			β (95% CI)	p-value	β (95% CI)	p-value	β (95% CI)	p-value
SE	>	SED	1.410 (0.330, 2.489)	0.011	1.038 (−0.216, 2.292)	0.104	1.763 (−0.156, 3.682)	0.071
		LPA	−0.861 (−1.729, 0.006)	0.052	−0.641 (−1.661, 0.379)	0.217	−1.102 (−2.590, 0.387)	0.144
		MVPA	−0.569 (−0.894, −0.244)	<0.001	−0.474 (−0.850, −0.097)	0.014	−0.786 (−1.416, −0.156)	0.015
		VMCPM	−9.102 (−14.126, −4.078)	<0.001	−7.323 (−13.277, −1.370)	0.016	−11.067 (−20.606, −1.528)	0.024
		VCPM	−5.176 (−7.945, −2.407)	<0.001	−4.491 (−7.726, −1.256)	0.007	−6.240 (−11.469, −1.010)	0.020
SOL	>	SED	−0.099 (−0.551, 0.352)	0.665	−0.026 (−0.518, 0.466)	0.918	−0.128 (−1.086, 0.829)	0.789
		LPA	0.061 (−0.299, 0.421)	0.739	−0.037 (−0.436, 0.363)	0.856	0.234 (−0.512, 0.980)	0.532
		MVPA	0.052 (−0.087, 0.191)	0.460	0.049 (−0.098, 0.195)	0.514	0.083 (−0.218, 0.383)	0.583
		VMCPM	1.035 (−1.091, 3.161)	0.339	0.752 (−1.573, 3.076)	0.524	2.374 (−2.216, 6.963)	0.304
		VCPM	0.920 (−0.258, 2.098)	0.125	0.745 (−0.522, 2.011)	0.247	1.717 (−0.861, 4.295)	0.187
TBT	>	SED	0.139 (−0.035, 0.313)	0.116	0.003 (−0.231, 0.237)	0.980	0.301 (0.059, 0.544)	0.015
		LPA	−0.140 (−0.278, −0.003)	0.046	−0.008 (−0.196, 0.180)	0.935	−0.269 (−0.453, −0.085)	0.005
		MVPA	0.003 (−0.052, 0.057)	0.924	0.018 (−0.055, 0.091)	0.632	−0.016 (−0.095, 0.063)	0.687
		VMCPM	−0.445 (−1.261, 0.371)	0.283	0.162 (−0.690, 1.013)	0.708	−0.915 (−2.097, 0.268)	0.128
		VCPM	−0.116 (−0.581, 0.349)	0.623	0.235 (−0.397, 0.866)	0.464	−0.527 (−1.210, 0.157)	0.129
TST	>	SED	0.234 (0.093, 0.375)	0.001	0.114 (−0.053, 0.282)	0.179	0.423 (0.202, 0.644)	<0.001
		LPA	−0.169 (−0.281, −0.056)	0.004	−0.066 (−0.201, 0.069)	0.338	−0.338 (−0.509, −0.167)	<0.001
		MVPA	−0.068 (−0.111, −0.024)	0.002	−0.053 (−0.105, −0.002)	0.042	−0.091 (−0.166, −0.017)	0.018
		VMCPM	−1.285 (−1.943, −0.627)	<0.001	−0.860 (−1.650, −0.069)	0.033	−1.987 (−3.096, −0.878)	<0.001
		VCPM	−0.675 (−1.042, −0.308)	<0.001	−0.465 (−0.909, −0.022)	0.040	−1.051 (−1.670, −0.432)	0.001

SE: sleep efficiency; SOL: sleep onset latency; TBT: total in bed time; TST: total sleep time; SED: sedentary time; LPA: light physical activity; MVPA: moderate-to-vigorous activity; VMCPM = vector magnitude average counts per minute; VCPM: vertical axis average counts per minute. SED, LPA & MVPA are standardized to 12 h per day. Significant p-values are highlighted in bold.

All models were adjusted for age, sex, GMFCS-level.