Ultradian sleep cycles: Frequency, duration, and associations
First published: 2024
Brief summary
Retrospective sleep study of NREM-REM ultradian cycles and individual/environmental associations.
Article
The study examined the recurring sequence of non-rapid-eye-movement and rapid-eye-movement sleep episodes that forms the human ultradian sleep cycle. It focused on the frequency and duration of these cycles and on the extent to which they vary among individuals and experimental conditions.
The analysis used retrospective sleep recordings from healthy participants who received an eight-hour sleep opportunity at their habitual bedtime under controlled laboratory conditions. Sleep cycles were identified from the progression of scored NREM and REM episodes across the night.
The results showed substantial variation between individuals in total cycle duration and in the lengths of the NREM and REM components. Cycle structure also changed across the night rather than remaining constant from the first cycle to the last.
Sleep pressure affected the organisation of the cycles. Sleep deprivation was associated with longer NREM sleep in the first cycle, whereas reduced sleep pressure produced by multiple naps was associated with longer REM episodes. The findings show that ultradian sleep timing is influenced by both individual characteristics and recent sleep history.
Source details and credits
- Source / publisher: Sleep Health / ScienceDirect
- Source type: Open-access study
- URL type: WWW
- Credits: Sleep Health / ScienceDirect
- URL: https://www.sciencedirect.com/science/article/pii/S2352721823002048