Cardiac Autonomic Hypofunction in Preschool Children with Short Nocturnal Sleep

Abstract

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

Impact of total sleep duration on blood pressure in preschool children

“…In the present study, the average total sleep duration ( ± SD) on weekdays, calculated from nocturnal sleep duration and mandatory nap time, was 624 ± 57 min, and this was of course longer than the nocturnal sleep duration (575 ± 42 min) in Japanese preschool children at the same ages (21). The average total sleep duration in our subjects at ages 5-6 years is consistent with those in the U.S. (2), Switzerland (7), and Iceland (23).…”

“…We have already reported that SBP, together with cardiac autonomic activities, was significantly decreased in preschool children with short nocturnal sleep ( < 600 min) as compared to those with long nocturnal sleep ( ≥ 600 min), but the SBP did not have any close relation to nocturnal sleep duration in using multiple regression analysis with independent variables of age, sex, Kaup index, and institute (21). By contrast, the link between total sleep duration and SBP, as mentioned above, was statistically significant, albeit the change in the SBP was small (Fig.…”

“…Despite the potential limitations involved in observational research, reported total sleep durations and measured blood pressure could be used in a survey kindergartens in Akita, northern Japan; and, their preschool children, who did not have past or present histories of serious illness such as heart, kidney, neurological or metabolic disease, were invited to participate in the study. Initially, 134 preschool children took part in this study (21), but 17 children were excluded because we could not confirm whether they did actually sleep during the mandatory nap time. In total, 79 kindergarteners and 38 nursery school children were enrolled.…”

“…The implication is that the potential onset of lifestyle-related diseases during childhood may originate from forcing adult lifestyles on children; namely, nursery school children frequently show short nocturnal sleep duration and delayed bedtime as compared to kindergarteners (8,21), and the delayed bedtime in the former would probably be due to the fact that most mothers with nursery school children work outside and often come home late for dinner (14). In light of the present outcomes, we would like to recommend that parents let their children at ages 5-6 years sleep for a total of 10-11 h because such children cannot correct their life environments by themselves.…”

“…Only an association between shortening of nocturnal sleep and low systolic blood pressure (SBP) has been suggested in preschool children (21). Nevertheless, a new question could be raised as to the difference of effects between nocturnal sleep duration and total sleep duration among such children, inasmuch as daytime naps may compensate for any sleep insufficiency on the previous night.…”