Blue-enriched light can improve sleep quality and daily activity in older adults living at home, according to a study from the University of Surrey, United Kingdom. Researchers found that this type of light therapy led to greater daytime activity, earlier bedtimes, regular sleep patterns and improved sleep quality, offering a promising, non-pharmacological approach to address age-related sleep challenges.

Sleep patterns often change with age, leading to difficulties falling asleep, waking up earlier, more frequent nighttime awakenings, and overall poorer sleep quality. These changes are linked to age-related changes in the eyes and reduced exposure to daylight, often due to decreased mobility and social interactions, alongside increased exposure to artificial light at night.

The study investigated the effects of different light conditions on adults ages 60 and older. One hundred and fifty-four individuals were recruited  through local newspapers advertisements, all with self-reported sleep problems (Pittsburgh Sleep Quality Index, PSQI>5). After exclusions for medication use, psychiatric/neurological history, eye disorders or recent travel across more than two time zones, a total of 36 participants were included in questionnaire analyses and 28 in actigraphy analyses.

Participants self-administered both a control white light and a blue-enriched white light for two hours in the morning and two hours in the evening over an 11-week period. Researchers  monitored sleep patterns and activity levels using wearable technology and sleep diaries.

The authors found that the timing of light is crucial: Blue-enriched light is only beneficial in the morning, while exposure in the evening makes it more difficult to fall asleep and causes more restless nights.

Daan Van Der Veen, Senior Lecturer in Sleep and Chronobiology at the university said, "Our research shows that carefully timed light intervention can be a powerful tool for improving sleep and day-to-day activity in healthy older adults. By focusing on morning blue light and maximizing daytime light exposure, we can help older adults achieve more restful sleep and maintain a healthier, more active lifestyle."

Débora Constantino, a postgraduate student at the university, added, "We believe that this is one of the first studies that have looked into the effects of self-administered light therapy on healthy older adults living independently, to help aid their sleep and daily activity. It highlights the potential for accessible and affordable light-based therapies to address age-related sleep issues without the need for medication."

To download the full study, published in GeroScience, click here