# Deep sleep (slow-wave sleep)

Deep sleep, also called slow-wave sleep (N3), is marked by high-amplitude 'delta' waves on the EEG, and the highest arousal threshold (it is the hardest stage to wake you from). It dominates the first third of the night. It drives growth hormone release, cardiovascular recovery, immune regulation, and the glymphatic clearance of metabolic waste from your brain. Deep sleep declines with age. And lower amounts are linked to poorer memory and a higher risk of neurodegenerative disease.

## Sources

- Stickgold R. (2005). Sleep-dependent memory consolidation. Nature. https://doi.org/10.1038/nature04286
- Rechtschaffen A, Kales A. (1968). A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. US Government Printing Office

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_Canonical: https://longevity-switzerland.com/en/glossary/deep-sleep-slow-wave-sleep · Part of Longevity Cities · Updated 2026-06-22_