The need for light increases with age as the pupil gets smaller and the lens thickens absorbing more light. People with an advanced age therefore need more intensive light to aid vision, and exposure to sufficient daylight is important in stimulating the diurnal rhythm.
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 age¹,².
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 times³. 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
One of the positive effects of adequate lighting for the elderly has been shown to be a reduction in depressive symptoms. In a study on blue-and-white light designed to provide circadian lighting, people with Alzheimer’s and related dementia experienced a reduction in depressive symptoms and longer sleep⁴.
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.
Sleep is an important factor to promote the wellbeing and recovery of patients.
1. 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
2. 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
3. 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.
4. 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