Modifications of sleep structure by brief forced awakenings at different times of the night.

Four subjects were awakened once a night for 10 min at either 01.30, 03.30 or 05.

Early rising or delayed bedtime: which is better for a short night's sleep?

The present study compares the effects on sleep and the subsequent period of wakefulness of delaying bedtime of 2 h or advancing rising time by 2 h in subjects clearly differentiated by morningness or eveningness in their circadian rhythms. Twelve young healthy good sleepers, six morning types (MT) and six evening types (ET), were selected. The data obtained from the second 24 h (night and day) with delayed bedtime (DB) and advanced rising time (AR) were compared with those obtained in the reference condition (R) with normal sleep schedules.

Sleep and body temperature in "morning" and "evening" people.

Three groups of young, normal sleepers were selected as morning types (MTs), evening types (ETs), and neither types (NTs) as determined by the Horne and Ostberg questionnaire. Sleep and rectal temperatures were recorded under three conditions: baseline nights (Cond. 1), sleep on the recovery day after 1 night of sleep deprivation (Cond.