title: The cardiac rhythm during waking and the various periods of sleep.
mesh_terms: D000328:Adult; D000367:Age Factors; D001146:Arrhythmia, Sinus / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology