Guest post by the New Buildings Institute

Researchers continue to broaden their knowledge about the ways light impacts the circadian system and rhythms such as the sleep/wake cycle. Generally, it’s been shown that exposure to strong light levels during daytime hours makes us more alert and focused through the day, while minimal light exposure in bedrooms at night leads to deeper, more restful sleep. Disruption to the circadian system brings with it a multitude of negative impacts on health, particularly in the elderly. Daylight patterns in particular are known to reinforce healthy circadian rhythms, but questions have remained as to the characteristics of artificial light in achieving similar results. A recent post-occupancy study at a healthcare center in New York shows how an experimental lighting upgrade design that emphasizes white light during the day and red light at night has improved resident well-being.

The results of the study were outlined in LD+A’s October 2012 article, “Maximizing Health and Sleep in the Elderly.” The study was conducted as part of a capital improvement project upgrading single-lamp and two-lamp corridor luminaires. Employing current photobiology research, the design team initially aimed to limit exposure to blue wavelengths (and artificial lighting) from the corridors at night. This wasn’t feasible due to the nature of the facility, where nurses needed to be able to safely navigate between rooms at all hours. The introduction of red night lighting proved to prevent sleep disturbances associated with the opening and closing of doors onto the corridor. As a result, improvements were noted in the areas of sleep, health and behavior. For sleep this included sleeping through the night, longer waking time during the day, and reduced insomnia.

Health improvements included “Lower incidence of illness (flu, colds)” and “Sustained reduction and stabilization of systolic and diastolic blood pressure readings.” Cited benefits to behavior included “lower incidence of night wandering,” “hallucinations ceased,” “aggression diminished,” “improved lucidity,” and “increased social participation.”

To learn more, visit ALG Online’s Health & Performance chapter which describes the ways in which light impacts visual performance, human health, mood, behavior and productivity. In addition to the circadian system, the human health section explores topics from eyestrain and flicker to well-being and lighting for the elderly.

(Accessing the ALG requires paying a subscription fee.)