Blue-enriched light can improve the sleep quality and daytime activity of older adults living at home, according to a new study from the University of Surrey. Researchers found that this type of light therapy led to more daytime activity, earlier bedtimes, more regular sleep patterns and improved sleep quality, offering a promising non-pharmacological approach to managing age-related sleep problems. Sleep patterns often change with age, leading to difficulties falling asleep, waking up earlier, waking up more often during the night, and poorer overall sleep quality.

These changes are associated with age-related changes in the eyes and less exposure to daylight, often due to decreased mobility and social interaction, and more exposure to artificial light at night, especially if living in nursing homes. The study published in GeroScience examined the effects of different light conditions on 36 adults aged 60 and older.

Morning Blue Light Therapy Improves Sleep and Daytime Activity in Older Adults

Participants self-exposed to both control white light and blue-enriched white light for two hours in the morning and evening over an 11-week period. Researchers carefully monitored sleep patterns and activity levels using wearable technology and sleep diaries. The study found that timing is crucial. They found that blue-enriched light is only beneficial in the morning, while exposure in the evening makes it harder to fall asleep and leads to more restless nights.

Dr. Daan Van Der Veen, lecturer in sleep and chronobiology at the University of Surrey, said: “Our research shows that a carefully designed light intervention can be an effective tool for improving sleep and daily activity in healthy older adults. By focusing on blue light in the morning and maximizing daylight exposure, we can help older adults get more restful sleep and maintain a healthier, more active lifestyle.”

Débora Constantino, a doctoral researcher at the University of Surrey, believes that this is one of the first studies to examine the effects of self-administered light therapy on healthy older adults living independently to support their sleep and daily activities. She highlights the potential for accessible and affordable light-based therapies to treat age-related sleep problems without the use of medication.

Blue Light Damage Increases With Age, Fly Research Suggests

The deleterious effects of daily, lifelong exposure to blue light emitted from phones, computers and appliances worsen with age, Oregon State University research suggests. The study, published in Nature Partner Journals Aging, looked at Drosophila melanogaster, the common fruit fly, an important model organism because it shares the same cellular and developmental mechanisms as other animals and humans.

Jaga Giebultowicz, an OSU College of Science researcher studying biological clocks, led a collaboration that examined the survival rate of flies kept in darkness and then placed in a constant blue light environment from light-emitting diodes (LEDs) at progressively older ages. The transitions from darkness to light occurred at two, 20, 40 and 60 days of age, and the study looked at the effect of blue light on the mitochondria of fly cells. Mitochondria function as the powerhouse of a cell, generating adenosine triphosphate (ATP), a chemical source of energy. In earlier research, Giebultowicz showed that prolonged exposure to blue light reduced the longevity of flies, regardless of whether it shined in their eyes.

The researchers found that certain reactions in the mitochondria were drastically reduced by blue light, while other reactions were reduced by blue light regardless of age. One can imagine that the blue light exposure in aging flies acts like an additional blow to an already existing injury. The work, which was partially funded by the National Institutes of Health, was carried out by Giebultowicz, Yujuan Song, Jun Yang and David Hendrix from the OSU College of Science, Matthew Robinson from the College of Public Health and Human Sciences, and Alexander Law and Doris Kretzschmar from the Oregon Health & Science University. The scientists point out that natural light is crucial to a person’s circadian rhythm – the 24-hour cycle of physiological processes such as brain wave activity, hormone production and cell regeneration, which are important factors in eating and sleeping habits. However, there is evidence that increased exposure to artificial light is a risk factor for sleep and circadian disorders. And with the widespread use of LED lighting and screens, people are increasingly exposed to light in the blue spectrum, as commonly used LEDs emit a high proportion of blue light.

A Shorter Lifespan

This technology, LED lighting, has not been in use long enough, even in most developed countries, to know its effects over the full human lifespan, according to Giebultowicz. There is a growing concern that prolonged exposure to artificial light, particularly blue-enriched LED light, could be detrimental to human health. Although the full effects of blue light exposure over the entire lifespan in humans are not yet known, the accelerated aging observed in short-lived model organisms should alert us to the potential for cell damage from this stressor, according to the researchers.

In the meantime, there are a few things people can do to help themselves without sitting in the dark for hours, the experts say. Glasses with yellow lenses filter out blue light and protect the retina. And smartphone, laptop and other device settings can be adjusted to block blue radiation. According to the researchers, the harmful effects of blue light on flies are highly age-dependent – the same duration of exposure to the same light intensity shortens lifespan and increases neurodegeneration more in old flies than in young ones.

In previous research, flies exposed to daily cycles of 12 hours of light and 12 hours of darkness had shorter lifespans than flies kept in total darkness or in light with the blue wavelengths filtered out. The flies exposed to blue light showed damage to their retinal cells and brain neurons and had impaired locomotion – the flies’ ability to climb the walls of their enclosures, a common behavior, was diminished. Some of the flies in the experiment were mutants that did not develop eyes, and even these eyeless flies showed impairments, suggesting that flies do not need to see the light to be harmed by it.