Bright light therapy lamps can improve sleep, activity levels, and circadian rhythms in older adults living in urban areas with limited exposure to natural light, according to researchers at the University of Surrey, UK. The team said the approach could offer a low-cost, non-drug way to support healthy aging. 

As part of the European ENLIGHTENme project, researchers recruited more than 200 participants ages 63 to 92 from three cities with differing seasonal daylight patterns -- Tartu, Estonia; Bologna, Italy; and Amsterdam, the Netherlands. After two weeks of baseline assessment, participants were split into a light supplementation group and given a therapy lamp to use at home, or a control group without a lamp.

Those with a lamp were instructed to turn it on within an hour of waking and off at least four hours before bedtime, for 12 weeks. All participants wore a wrist actigraphy monitor and a pendant light sensor to measure activity levels and exposure to light. The study was repeated across all seasons.

Participants with higher baseline natural light exposure showed more daytime activity, more consolidated wakefulness, and better reported sleep quality. Among those using a lamp, "morning types" who began light exposure earlier were more active and had less disrupted rest-activity rhythms than those who started later. Finishing light exposure earlier in the day was linked to less rest-activity fragmentation overall.

Participants with metabolic conditions, including high blood pressure, diabetes, obesity, or cardiovascular disease, had lower total light exposure at baseline than those without such conditions.

“This is an exciting discovery and provides real-world evidence that light is a simple, non-pharmacological, and potentially cost-effective intervention, which, from a public health policy perspective, could help support healthy aging, said coauthor Débora Constantino, University of Surry. “These findings highlight a clear opportunity for policymakers to integrate structured indoor light supplementation into community care frameworks and care home guidelines.” 

To download the full study, published in the Journal of Pineal Research, click here: https://onlinelibrary.wiley.com/doi/10.1111/jpi.70174