In conclusion, there is abundant evidence that there are
marked changes in ANS activity as measured by HRV during sleep. However, little is known about gender differences in HRV during sleep, and controversy remains
regarding the contributions of the parasympathetic and
sympathetic branches to the observed differences in sympathovagal balance during NREM and REM sleep in
healthy human subjects. The aim of this study was to compare the autonomic regulation of the heart rate as assessed
by spectral analysis of HRV data during waking, NREM,
and REM sleep in healthy males and females.