Abstract P245: Sleep Variability and Cardiac Autonomic Modulation in Adolescents - Penn State Child Cohort (PSCC) Study
Objectives: To assess the relationship between habitual sleep time and its variability and cardiac autonomic modulation (CAM) in a population-based sample of adolescents.
Methods: We used available data from the first 300 adolescents who have completed the follow up examinations in the population-based PSCC study. We used actigraphy to assess sleep time for 8 consecutive nights. Excluding the first night, we calculated each participant’s 7-night mean sleep time, and its standard deviation. The latter was used as a measure of sleep time variability. CAM was assessed by heart rate variability (HRV) analysis of beat-to-beat normal R-R intervals from a 39-hour high resolution Holter ECG. The HRV indices in frequency domain [high frequency power (HF), low frequency power (LF), and LF/HF ratio] and time domain [standard deviation of normal RR intervals (SDNN), and the square root of the mean squared difference of successive normal RR intervals (RMSSD), and heart rate (HR)] were calculated on a 30-minute basis (78 repeated measures). Mixed-effects models were used to assess the sleep and HRV relationships.
Results: The mean age was 17.2 yrs (SD=2.06), with 56% male and 78% white. The 7-night mean sleep time and sleep time variability were 6.89 hrs (SD=0.82) and 1.22 hrs (SD=0.60), respectively. The age, race, and sex-adjusted regression coefficients for a one SD increase in the mean sleep time (0.82 hr) and sleep time variability (0.60 hr) are presented in Table 1. In summary, higher sleep time variability, but not the sleep time, is associated with lower HRV and higher HR in this population-based adolescent sample.
Conclusion: Higher night-to-night sleep time variability is associated with lower HRV, indicating adverse effects of sleep variability on the cardiac autonomic modulation in healthy adolescents.
- © 2013 by American Heart Association, Inc.