Researchers say blue light exposure in the morning may be a healthier alternative to taking sleep medications. (amenic181/Shutterstock)

GUILDFORD, England — Getting older brings many changes, and unfortunately, worse sleep is often one of them. Many seniors struggle with falling asleep, waking up frequently during the night, and generally feeling less rested. But what if something as simple as changing your light exposure could help?

A new study from the University of Surrey has found that the right light, at the right time, might make a significant difference in older adults’ sleep and daily activity patterns. This research, published in GeroScience, reveals that morning exposure to blue-enriched light can be beneficial, while that same light in the evening can actually make sleep problems worse.

“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,” explains study author Daan Van Der Veen from the University of Surrey, in a statement. “By focusing on morning blue light and maximizing daylight exposure, we can help older adults achieve more restful sleep and maintain a healthier, more active lifestyle.”

Why light timing matters

So why do older adults have more sleep troubles in the first place? Part of the problem lies in the aging eye. As we get older, our eyes undergo natural changes—the lens yellows, pupils get smaller, and we have fewer photoreceptor cells. All these changes mean less light reaches the brain’s master clock, located in a tiny region called the hypothalamic suprachiasmatic nuclei (SCN).

That yellowing lens is particularly problematic because it filters out blue light wavelengths specifically. It’s like wearing subtle yellow sunglasses all the time. This matters because blue light (wavelengths between 420 and 480 nanometers) is especially powerful at regulating our body clocks. With less blue light reaching their brains, older adults’ internal clocks can become weaker and more prone to disruption.

Many seniors also spend less time outdoors and have fewer social engagements, further reducing their exposure to bright natural light. Meanwhile, they might be getting too much artificial light at night, which can confuse the body’s natural rhythms.

The Surrey researchers wanted to see if they could improve sleep for older adults living independently at home by tweaking their light exposure. They recruited 36 people aged 60 and over who reported having sleep problems. None were in full-time employment, and all were free from eye disorders or other conditions that might complicate the study.

Over an 11-week period during fall and winter (when natural daylight is limited in the UK), participants followed a carefully designed protocol. They spent one week establishing baseline measurements, followed by three weeks using either blue-enriched white light (17,000 K) or standard white light (4,000 K) for two hours each morning and evening. After a two-week break, they switched to the other light condition for three weeks, followed by another two-week washout period.

Participants used desktop light boxes while going about normal activities like reading or watching TV. They wore activity monitors on their wrists around the clock and light sensors around their necks during the day. They kept sleep diaries and collected urine samples to measure melatonin metabolites, markers indicating how their internal clocks were functioning.

Morning light helps, evening light hurts

The results were telling. Longer morning exposure to the blue-enriched light significantly improved the stability of participants’ daily activity patterns and reduced sleep fragmentation. By contrast, evening exposure to that same light made it harder to fall asleep and reduced overall sleep quality.

Another key discovery was that participants who spent more time in bright light (above 2,500 lux, roughly the brightness you’d experience outdoors on a cloudy day) had more active days, stronger daily rhythms, and tended to go to bed earlier. This finding reinforces long-standing advice from sleep experts: getting outside during the day is really important for good sleep.

Morning people (early birds) naturally started their morning light sessions earlier than night owls. However, most participants used their evening light sessions at similar times, suggesting that social habits might influence evening routines more than biological clocks.

The women in the study showed more variable activity patterns throughout the day than men, and those who took more daytime naps had less stable daily rhythms and were generally less active.

Practical tips

By the end of the study, participants reported meaningful improvements in their sleep quality. This means light therapy could be a potential alternative to sleep medications, which often come with side effects.

“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 aid their sleep and daily activity,” says study author Débora Constantino, a postgraduate research student. “It highlights the potential for accessible and affordable light-based therapies to address age-related sleep issues without the need for medication.”

For older adults seeking better rest, the advice is clear:

• Get bright, blue-enriched light in the morning: Use a light box or spend time outdoors after waking up.
• Dim the lights in the evening: Reduce exposure to phones, tablets, and bright overhead lights.
• Stay consistent: Establishing regular morning and evening routines can further support healthy sleep patterns.

This approach isn’t just for people in care homes or those with cognitive impairments; it can also benefit healthy, independent older adults. With an aging population worldwide, finding simple and effective strategies to improve sleep has never been more important. The right light at the right time might be a key part of aging well.