Older adults living in cities often get far less bright light than their bodies expect, and it shows up in fragmented sleep, lower daytime activity, and out-of-step biological rhythms.
A new study published on September 2, 2026 in the Journal of Pineal Research suggests something surprisingly simple can push back: a bright therapy lamp switched on within an hour of waking.
The trial, part of the EU-funded ENLIGHTENme project, followed more than 200 people aged 63 to 92 across three European cities with very different daylight patterns.
Half received a light therapy lamp for their home; all wore wrist activity monitors and pendant light sensors so researchers could track how much light they actually got and how well they moved and slept.
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What the lamp changed
Participants who used the lamp early in the morning saw meaningfully more daytime activity and less fragmented rest-activity rhythms, the pattern of when the body is active and when it rests.
Turning the lamp off well before bedtime also helped stabilize those rhythms, according to the research summary from the University of Surrey team.
Baseline light exposure mattered on its own.
People who caught more natural light during the day tended to be more active, stayed awake more consistently, and reported better sleep quality.
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Participants living with metabolic disorders such as type 2 diabetes had significantly lower total light exposure than their healthier peers.
"Exposure to daytime light is crucial for regulating our circadian rhythms and sleeping patterns," said Dr. Daan van der Veen, Senior Lecturer in Sleep and Chronobiology at the University of Surrey.
Why aging bodies need more light
The body's internal clock is set largely by bright light hitting the eyes in the morning. With age, that signal weakens.
NIH-published research has documented that circadian rhythms shift earlier in older adults, melatonin production drops, and age-related eye changes such as cataracts reduce how much light reaches the brain's pacemaker.
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Weakened or disrupted rhythms have been linked to higher dementia risk in older adults.
City life compounds the problem. Many older residents spend most of the day indoors, where typical lighting sits far below the levels the circadian system responds to.
A separate 2025 study in GeroScience of 36 older adults with sleep problems found that morning blue-enriched light of around 2,500 lux improved rest-activity stability and reduced sleep fragmentation, while evening light use worsened sleep.
What the Surrey team recommends in practice
The lamps in the trial were placed at head height in the main room, used within one hour of waking, and switched off at least four hours before sleep.
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That timing matters. Morning light advances and strengthens the clock, while late-evening light pushes it in the wrong direction.
Bright light therapy lamps used in circadian research typically deliver 2,500 to 10,000 lux for 30 minutes to two hours a day, according to a Cochrane protocol published in September 2025 that is preparing a full overview of the evidence in older adults.
Anyone with eye disease, bipolar disorder, or on medications that increase light sensitivity should ask their doctor before starting light therapy.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.