Senior living environments: evidence-based lighting design strategies.

Objective: To review from an architectural lighting perspective the effects of indoor lighting on the health and well-being of people in senior living environments.

Background: The role of circadian rhythms in people with chronic disorders continues to be a focus of laboratory research and clinical trials. Beneficial, evidence-based indoor lighting design strategies are being considered for senior living environments, particularly for residents who have limited access to natural bright light.

Methods: Articles published 2002-2012 reporting the results of prospective, randomized, controlled clinical trials (RCTs) were accessed using the U.S. National Library of Medicine PubMed site using the following search terms: "light, sleep, circadian, randomized, controlled, nursing home" and "light, sleep, circadian, randomized, controlled, elderly."

Results: The search resulted in 48 citations, of which 18 meet our pre-search criteria. Data from these RCTs indicate options such as programmable, 24-hour lighting algorithms that may involve light intensity, lighting duration, spectra (wavelength) and lighting timing sequences

Conclusions: Valid and actionable data are available about circadian rhythms, sleep, and human health and well-being that can inform the design of lighting for long-term care. Evidence-based architectural design of a 24-hour light/dark environment for residents may mitigate symptoms of circadian disruption; evidence-based management of darkness is as important as evidence-based management of light. Further research is needed into the long-term circadian health needs of night staff members in order to understand the effects of shift work while, at the same time providing the highest level of care.

Keywords: Design process, elderly, evidence-based design, lighting, literature review.