Spending more time indoors, declining vision, and other age-related changes are suspected to contribute to alterations in senior living residents’ internal clocks, or circadian rhythms. In a recent study, researchers used bright light therapy to help reset nursing home residents’ circadian rhythms.
Thirty-seven nursing home residents (33 women) participated in a three-week bright light therapy intervention. For 90 minutes during late morning, five days a week, residents sat around a table doing usual daily activities, such as reading or socializing. In the first and third weeks, standard lighting was used over the table, but in the second week, much brighter lighting was used. Participants completed pre- and post-intervention measures of sleep quality and cognitive function, and wore sensors on the wrist and arm that recorded activity and circadian body temperature, as well as a pendant that recorded light exposure throughout the day.
As expected, the bright light therapy helped to improve residents’ circadian rhythms. During the daytime in week 2, residents showed rhythms that more closely matched what is typical for active, waking hours, while nighttime rhythms more closely matched those observed during rest. This even persisted into week 3, when the bright light therapy was no longer used, suggesting this helped to reset residents’ internal clocks.
In addition to improved circadian rhythms, participants reported better sleep satisfaction and less insomnia after the intervention. Hypersomnia (excessive tiredness), however, was not affected. Participants even saw improvements in cognitive function, mostly reflected in improvements in memory and a slight improvement in attention.
Light exposure and type of lighting are increasingly being researched in senior living settings. While proper lighting should be incorporated throughout a community, this study showed that only 90 minutes of bright light per day was enough to have a positive impact on residents’ sleep and cognitive function. The relatively low number of participants and lack of a control group in this study are limitations to address in future research.
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Rubiño JA, Gamundí A, Akaarir M, Canellas F, Rial R, and Nicolau MC. Bright Light Therapy and Circadian Cycles in Institutionalized Elders. Frontiers in Neuroscience, (2020); 14(359).