Heart rate variability associated with rapid eye movements during sleep

To understand the association of heart rate control with rapid eye movement, we studied heart rate and eye movement continuously during sleep in 10 young, healthy subjects who do not suffer from any sleep disorder. The study took place over 3 nights in a sleep room. Polysomnographic recordings included electrooculogram (EOG), EEG, chin electromyogram (EMG) and ECG. The first and second nights were used for habituation, and the data obtained on the third night was used for analysis. Sleep stages were scored using standard R-K criteria. Each eye movement was extracted from EOG with semi-automated algorithm followed by physicianpsilas confirmation. Population averaged results for DFA exponents of HRV were around 1/2 for non-REM sleep and 0.82 for REM sleep. Most notably, instantaneous heart rate showed distinctive increase within 30 sec of the rapid eye movements (p=0.04) with modification by the number of succeeding rapid eye movements.