Insomnia Symptoms and Sleep Duration Are Associated with Impaired Cardiac Autonomic Modulation in Children

Limited population-based data from children are available to investigate the associations between insomnia and sleep duration in relationship to impaired cardiac autonomic modulation (CAM). Therefore, the objective of this study is to examine the cross-sectional associations between insomnia symptoms, sleep duration, and CAM in a population-based sample of children. All 616 children were randomly selected from Central Pennsylvania to participate in a one-night polysomnography (PSG) study in a sleep laboratory. The Pediatric Behavior Scale was used to assess parent-reported insomnia. Sleep duration was assessed objectively by PSG. CAM was measured by heart rate variability (HRV) analysis of 9-hour-beat-to-beat RR intervals. Multivariate linear regression models were used to assess the association between insomnia, sleep duration and HRV. The mean (SD) age was 9.2 (1.7) years, with 25.5% non-white and 48.9% male. After adjusting for age, race, gender, BMI percentile, %REM sleep, apnea-hypopnea-index, sleep latency, and sleep efficiency, the means(SE) of HRV indices were lower in children with insomnia than in children without: 6.56 (0.07) vs. 6.78 (0.04) m2 on logHF, respectively; and 6.47 (0.06) vs. 6.61 (0.03) m2 on logLF, respectively (all P < 0.05). There is a trend towards a significant lower time domain HRV indices, faster HR, and higher LF/HF ratio in children with insomnia symptoms. There is a similar pattern of association between shorter objective sleep duration and HRV. Insomnia symptoms and shorter objective sleep duration are associated with lower HRV and higher HR and LF/HF ratio, indicative of disturbance of CAM towards more sympathetic and lower parasympathetic modulation. These data provide supporting evidence of physiological activation associated with insomnia and short sleep duration even in very young children.