# Sleep latency

Sleep latency is how long it takes you to fall asleep, from lights-out to the first moment of sleep. It is usually measured in minutes during a sleep study (polysomnography). A latency of about 10 to 20 minutes is considered healthy. A very short latency (under roughly 5 to 8 minutes) can signal sleep deprivation or excessive daytime sleepiness. A persistently long one points to insomnia or a circadian misalignment. It is a core metric in sleep studies and in the 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-switzerland.com/en/glossary/sleep-latency · Part of Longevity Cities · Updated 2026-06-22_