Hospital Lighting Aligned with Circadian Rhythm Supports Recovery

Hospital lights are generally intense and glaring. Some hospitals have begun using dimmer, intelligently designed lighting to support health and reduce energy consumption.

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Strong, uniform light disrupts patients' and staff's circadian rhythms (biological clocks), linked to general health. Appropriate circadian lighting can help them feel safe at night, sleep better and recover faster. Benefits may appear after at least 2 weeks.

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Light suppresses melatonin; altering the sleep-wake cycle partly controlled by it can cause insomnia, daytime sleepiness, depression, increased painkiller needs and delayed recovery. Without synchronization, physical functions and behavior suffer and risks of heart disease, diabetes and some cancers may rise. Research suggests hospital lighting following natural daily cycles is a sensible way to synchronize biological clocks, with substantial health benefits.

These changes form part of post-stroke care at Central Hospital, Karlstad, Sweden. Source: Chromaviso

Studies designing natural light over 24 hours show good results in settings from nursing homes to neonatal intensive care. Benefits have been observed, for example, in multiple myeloma patients undergoing bone marrow transplantation, Alzheimer's patients, and in those continuing rehabilitation after stroke, clinical benefits have been observed.

The circadian system is sensitive to short-wave blue light, which suppresses melatonin. Clear daylight has bluish-white tones. Soft yellow light does not stop melatonin release; circadian-aware hospitals use yellow tones in evenings and early mornings, followed by lighting appropriate for a dark night.

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Studies in Alzheimer's patients ongoing since 2010 show considerable success in normalizing sleep. Fatigue, depression and agitation decrease substantially.

Researchers recently partnered with New York's Mount Sinai Hospital to examine circadian lighting in multiple myeloma patients undergoing transplantation. Initial data show that during 2 to 3 weeks of hospital care, sleep improved and fatigue decreased.

Sleep is central to healing, affecting cognition, pain, hormonal balance and immunity. Circadian lighting to regulate hormonal and immune systems may reduce sedation and painkiller needs and accelerate recovery.

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A Danish trial compared post-stroke patients: 45 randomized to circadian lighting and 39 receiving standard lighting during rehabilitation, evaluating depression and fatigue.

At the end of the study, discharged patients receiving circadian lighting during stroke rehabilitation had significantly lower depression levels than controls. They also scored lower for sleepiness. Thus, this study again observed a positive contribution of circadian light to treatment and rehabilitation.

Circadian lighting appropriate to our biological clock therefore appears effective for better outcomes. It is easy to foresee future use in most buildings, including homes and offices.

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