Light

How much light in the evening for good sleep?

Short answer

Researchers advise little clock-active light in the evening: at most 10 lux melanopic EDI from 3 hours before bedtime, and at most 1 lux in the bedroom.

Light day: A 24-hour day: at least 250 lx during the day, at most 10 lx in the evening (3 hours before sleep), at most 1 lx melanopic EDI during sleep. — **Light day** — A 24-hour day: at least 250 lx during the day, at most 10 lx in the evening (3 hours before sleep), at most 1 lx melanopic EDI during sleep. (The text inside the figure is in Dutch.)

Explanation

Light does not only help us see. It also steers the body clock. Researchers measure this with 'melanopic EDI', taken at eye level. An international expert group published guideline values for day, evening and night in 2022. Dimmed, warmer light with little blue gives a lower melanopic value at the same brightness.

Rules of thumb

Evening (from 3 hours before bedtime): at most 10 lux melanopic EDI at eye level. [SW-S04]
Bedroom while sleeping: at most 1 lux melanopic EDI. [SW-S04]
Getting up at night: use dim light, at most 10 lux melanopic EDI. [SW-S04]

Pitfalls

An ordinary lux meter does not measure melanopic EDI; a figure from an app is at best an indication. [SW-S04]
These are scientific recommendations, not a legal standard. [SW-S04]

Search terms

These search terms are in Dutch; only terms that also find a topic in English are links.

slaap biologische klok melatonine avondlicht dimmen

Read also

General information, not personal advice. Check the source and reference date.

Sources

SW-S04 Recommendations for daytime, evening, and nighttime indoor light exposure (Brown e.a., 2022) — PLOS Biology (Reference date 2026-09-27)

Reference date: 2026-09-27 · Translated with AI from the Dutch original.