Tohoku J. Exp. Med., 2006, 208(3)

Cardiac Autonomic Hypofunction in Preschool Children
with Short Nocturnal Sleep

MARI SAMPEI, KATSUYUKI MURATA, MIWAKO DAKEISHI and DONALD C. WOOD¹

Departments of Environmental Health Sciences and ¹Social Medicine, Akita University School of Medicine, Akita, Japan

Preschool children with sleep deficit may suffer from autonomic symptoms or hypotension. Heart rate variability, reflecting cardiac parasympathetic and sympathetic activities, and blood pressure were assessed to clarify the effects of nocturnal sleep duration on cardiac autonomic function in 134 preschool children aged 5 and 6 years. Parents reported their children's typical bedtimes and wake times for weekdays. In the children, the mean nocturnal sleep duration (± standard deviation) was 575 ± 42 min. The parasympathetic and sympathetic activities and systolic blood pressure (SBP) were significantly lower in the 80 children with short sleep (nocturnal sleep duration < 10 hrs) than in the 54 children with long sleep (??10 hrs). Only the SBP was positively correlated with nocturnal sleep duration in the children (p < 0.001); also, short nocturnal sleep duration was significantly related to hypotension (SBP < 100 mmHg), as judged by multiple logistic regression analysis. Among the children, inverse correlations were seen between the parasympathetic activity and SBP and between the sympathetic activity and diastolic blood pressure (p < 0.05). These findings indicate that shortening of nocturnal sleep is associated with cardiac autonomic hypofunction and low SBP in preschool children. We suggest that sleep duration is an important predictor for autonomic development in childhood.

keywords —— nocturnal sleep duration; cardiac parasympathetic and sympathetic activities; blood pressure; preschool children

©2006 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2006, 208, 235-242

Received December 21, 2005; revision accepted for publication December 30, 2005.
Correspondence: Katsuyuki Murata, M.D., Department of Environmental Health Sciences, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.

e-mail:winestem@med.akita-u.ac.jp