orthodox sleep nonrapid eye movement sleep NREM sleep nonrapid eye movement NREM
orthodox_sleep%1:26:00:: nonrapid_eye_movement_sleep%1:26:00:: nrem_sleep%1:26:00:: nonrapid_eye_movement%1:26:00:: nrem%1:26:00::
a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur; accounts for about 75% of normal sleep time