Time-varying correlations between delta EEG power and heart rate variability in midlife women: The SWAN Sleep Study.

No studies have evaluated the dynamic, time-varying relationship between delta electroencephalographic ( EEG) sleep and high frequency heart rate variability ( HF- HRV) in women. Delta EEG and HF- HRV were measured during sleep in 197 midlife women ( M_age = 52.1, SD = 2.2). Delta EEG- HF- HRV correlations in nonrapid eye movement ( NREM) sleep were modeled as whole-night averages and as continuous functions of time. The whole-night delta EEG- HF- HRV correlation was positive. The strongest correlations were observed during the first NREM sleep period preceding and following peak delta power. Time-varying correlations between delta EEG- HF- HRV were stronger in participants with sleep-disordered breathing and self-reported insomnia compared to healthy controls. The dynamic interplay between sleep and autonomic activity can be modeled across the night to examine within- and between-participant differences including individuals with and without sleep disorders. [ABSTRACT FROM AUTHOR]