# Sleep latency

Sleep latency is the time from lights-out to the first epoch of sleep, typically measured in minutes during polysomnography. A latency of about 10 to 20 minutes is considered healthy; very short latencies (under roughly 5 to 8 minutes) can indicate sleep deprivation or excessive daytime sleepiness, while persistently longer values suggest insomnia or circadian misalignment. It is a core metric in polysomnography and consumer sleep trackers used in longevity contexts.

## Sources

- Carskadon MA, Dement WC, Mitler MM et al.. (1986). Guidelines for the Multiple Sleep Latency Test (MSLT): a standard measure of sleepiness. Sleep. https://doi.org/10.1093/sleep/9.4.519

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_Canonical: https://longevity-germany.com/en/glossary/sleep-latency · Part of Longevity Cities · Updated 2026-01-15_