The problem of "sympathetic tone" with particular respect to sleep.
D001794:Blood Pressure; D004569:Electroencephalography; D005769:Gastrointestinal Motility; D006321:Heart / Q000294:innervation; D006339:Heart Rate; D006801:Humans; D009476:Neurons, Efferent / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000502:physiology; D011311:Pressoreceptors / Q000502:physiology; D012890:Sleep; D012895:Sleep, REM; D013564:Sympathetic Nervous System / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology; D014851:Wakefulness