The opportunity for institutionalized elderly to synchronize their circadian clock to the solar day by daylight is often small. The circadian rhythm directs the endogenous sleep hormone melatonin and the activation hormone cortisol which boosts energy and alertness in the morning. The amplitude of these hormones diminishes with age²,³.
Among elderly, sleep related problems are common. Earlier bedtimes and wake-up times and frequent awakenings during sleep characterize nocturnal sleep patterns of older adults giving a more fragmented sleep with less quality.
Inadequate lighting has been found to be a contributing factor to accidental falls causing hip fractures and da- maging head injuries. Inadequate light increased the risk of a fall by 1,5 times¹. Fall prevention where light is one part is thus an important consideration for the design of the homes of the elderly and in care facilities.
Decrease depression symptoms
A positive effect of a restored circadian rhythm through appropriate light has shown an expected preventive effect through a decrease of depressive symptoms. This seems to be a result of direct mood enhancing effects of light and indirect mood preventing effects through a restoration of the sleep-wake cycle⁸.
Benefit ADRD patients
Alzheimer’s disease and related dementia (ADRD) is the most common mental disorder among elderly Americans. Studies comparing healthy adults with patients with ADRD have revealed that the circadian rhythm is more disrupted among those with ADRD and that this disruption is more pronounced during the winter months³. Other studies have shown reduced agitation and nighttime activitiy among ADRD patients following exposure of morning light, and a greater effect of light than prescription of sleep medicines.
1. Paul S, Yuanlong L. Inadequate light levels and their effect on falls and daily activities of community dwelling older adults: A review of literature. New Zeal J Occup Ther. 2012.
2. Karasek M. Melatonin, human aging, and age-re- lated diseases. Exp Gerontol. 2004;39(11-12 SPEC. ISS.):1723 1729.doi:10.1016/j.exger.2004.04.012
3. Hanford N, Figueiro M. Light therapy and Alzheimer’s disease and related dementia: Past, present, and future. J Alzheimer’s Dis. 2013. doi:10.3233/JAD-2012-121645
8. Bedrosian TA, Nelson RJ. Timing of light exposure affects mood and brain circuits. Transl Psychiatry. 2017;7(1):1-9. doi:10.1038/tp.2016.262