Why Older Adults Need More Daylight–And How to Get It

Older eyes need more light, and most people aren’t getting it.

A recent study of 202 healthy older adults found that simply being exposed to more light, at the right time, could improve their sleep and energy levels.

Why Daylight Matters More With Age

The eyes contain light-sensitive cells that report directly to the brain regions controlling sleep and wakefulness, Greg Elder, a sleep and circadian researcher at Northumbria University in the UK, told The Epoch Times. Daylight is what keeps the internal clock set correctly. It promotes alertness during the day and helps trigger melatonin, the hormone that signals the body it’s time to wind down, in the evening.

As we age, changes in the eyes make us “less responsive to light,” said Elder, who was not involved in the new study. Beginning around 50, the pupil shrinks, and the lens clouds slightly, letting in less of the blue light that the circadian system relies on most. The amount of crucial light reaching the retina can fall by as much as 72 percent between ages 10 and 80, and this can affect our sleep.

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“Light is the most important cue for our circadian system,” Elder said.

Then there is the indoor problem.

An older adult may spend much of the day inside, receiving relatively little bright light even when the sun is shining outside. The result can be a weaker contrast between bright days and dark nights—the very contrast that helps keep the body’s clock on schedule, Mariana Figueiro, director of the Light and Health Research Center at Mount Sinai, who was not involved in the study, told The Epoch Times.

This is where supplemental light can help through the form of bright lamps. “Don’t try to get that from your ceiling fixture because you’re going to need a heck of a lot of light coming from the ceiling to be able to get the light that you need at the eye,” Figueiro said.

For older adults who don’t get enough outdoor light, supplemental light during the day can help their eyes get enough light to correct their biological clock.

Who May Benefit Most?

Older adults getting the least natural daylight appeared to have the most to gain from supplemental light.

Ninety-eight participants were assigned to use lamps capable of producing up to 10,000 lux at close range. Lux is a measure of the intensity of light as seen by the human eye. They turned them on within an hour of waking, used them for at least two hours during the day, and switched them off at least four hours before bedtime.

The study found that timing mattered: Participants who began using the lamp earlier in the day had greater daytime activity and less fragmented patterns of rest and activity than those who began later.

Those with more daylight exposure at baseline were more active and reported better sleep, and were three times as likely to describe their sleep quality as good as those in the lowest exposure group.

That is especially relevant for people whose daily routines keep them indoors. Some older adults spend much of their time at home or in care settings, Elder said. Others may have limited mobility, wake before sunrise, or face long, dark winters. For them, the problem may not be a lack of light in an absolute sense—it may be that the day never gets bright enough, or for long enough, at the right time.

How to Get More Daytime Light

The best way to get more daytime light is to get it from the sun. But if that isn’t possible, you may assume you need a 10,000-lux light box, like what the researchers used in the study.

However, Figueiro, whose research center is an ENLIGHTENme partner, has also studied other ways to strengthen daytime light exposure in people with mild cognitive impairment and conditions such as dementia and Parkinson’s disease.

Nevertheless, the group using the lower-lumen lamps saw improvements on the memory portion of a standard Alzheimer’s disease assessment compared to the placebo group.

Figueiro’s advice is to shape light throughout the whole day:

Importantly, she added, the goal isn’t to make your home brighter all day. It’s to restore the contrast between day and night that the body’s clock depends on.

A simple rule of thumb is: “bright days, dim evenings, dark nights,” Figueiro said.

If You Choose a Light Box

A light box can be useful when weather, mobility, schedule, or the home environment makes it difficult to get enough daylight. Therapeutic lamp boxes are usually marketed online for seasonal affective disorder, or SAD—a type of depression that typically returns in fall or winter—have an intensity of 10,000 lux and are meant for use for only 20 to 30 minutes after waking. But these lamps are not always the right tool for healthy aging.

If you do use one, don’t rely on the “10,000-lux” label alone because a lamp may produce 10,000 lux only at the manufacturer’s specified distance.

Look for a device that:

People with bipolar disorder, significant eye disease, or medications that increase sensitivity to light should consult a clinician before starting bright-light therapy.

“You don’t need to have those very bright light boxes,” Figueiro said. Sometimes the simplest first step is just opening the curtains.