Endring av kveldslys på sykehus kan gi mindre forstyrret døgnrytme og forbedre søvnen

Blokkering av blått lys har vist å redusere de negative effektene av kunstig kveldslys på døgnrytmen i laboratorieforsøk, men dette har ennå ikke blitt vist i naturalistiske omgivelser. Forskere fra NTNU, St Olavs hospital, University of Newcastle og Novelda AS har i denne studien undersøkt melatonin-nivåer, søvn, nevrokognitiv aktivering og bivirkninger hos friske frivillige forsøkspersoner. Studien ble gjennomført på et nytt psykiatrisk sykehus, hvor alle lyskilder i alle rom var blokkerte for blått lys mellom klokken 18:30 og 07:00 i den ene halvdelen av enheten, mens den andre halve enheten hadde standardbelysning. Tolv friske voksne bodde i fem dager i hver enhet i en randomisert cross-over-studie. Forskerne konkluderer med at det er mulig å skape et kveldsmiljø som har positiv innvirkning på døgnrytme og søvn uten alvorlige bivirkninger. Videre konkluderer de med at potensielle fordeler ved å designe sykehusenheter som tar vare på døgnrytmen bør gi grunnlag for studier i både kliniske og ikke-kliniske populasjoner.

The evening light environment in hospitals can be designed to produce less disruptive effects on the circadian system and improve sleep

Daniel Vethe, Jan Scott, Morten Engstrøm, Øyvind Salvesen, Trond Sand, Alexander Olsen, Gunnar Morken, Hanne S Heglum, Kaia Kjørstad, Patrick M Faaland, Cecilie L Vestergaard, Knut Langsrud, Håvard Kallestad

Studien er publisert i SLEEP

Study objectives: Blue-depleted lighting reduces the disruptive effects of evening artificial light on the circadian system in laboratory experiments, but this has not yet been shown in naturalistic settings. The aim of the current study was to test the effects of residing in an evening blue-depleted light environment (LE) on melatonin levels, sleep, neurocognitive arousal, sleepiness and potential side-effects.
Methods: The study was undertaken in a new psychiatric hospital unit where dynamic light sources were installed. All light sources in all rooms were blue-depleted in one half of the unit between 1830h and 0700h (melanopic lux range: 7 - 21, melanopic equivalent daylight illuminance range (M-EDI): 6-19, photopic lux range: 55-124), whereas the other had standard lighting (melanopic lux range: 30-70, M-EDI range: 27-63, photopic lux range: 64-136), but was otherwise identical. Twelve healthy adults resided for five days in each light LE in a randomized cross-over trial.
Results: Melatonin levels were less suppressed in the blue-depleted LE (15%) compared with the normal LE (45%) (p=0.011). DLMO was phase advanced more (1:20h) after residing in the blue-depleted LE than after the normal LE (0:46h) (p=0.008). Total sleep time was 8.1 minutes longer (p=0.032), REM sleep 13.9 minutes longer (p<0.001), and neurocognitive arousal was lower (p=0.042) in the blue-depleted LE. There were no significant differences in subjective sleepiness (p=0.16) or side-effects (p=0.09).
Conclusion: It is possible to create an evening light environment that has an impact on the circadian system and sleep without serious side-effects. This demonstrates the feasibility and potential benefits of designing buildings or hospital units according to chronobiological principles and provide a basis for studies in both non-clinical and clinical populations.