title: Heart-rate variability in sleep and wakefulness.
mesh_terms: D000328:Adult; D001143:Arousal; D004562:Electrocardiography; D004569:Electroencephalography; D006339:Heart Rate; D006801:Humans; D008297:Male; D012890:Sleep; D012895:Sleep, REM; D013997:Time Factors; D014851:Wakefulness