It's well known that older adults need higher levels of light to see properly. But according to a new Dutch study published in the Journal of American Medicine, higher light levels can also reduce the affects of dementia in older adults.
According to John Bachner, communications director for the National Lighting Bureau, our bodies regulate how much melatonin to produce based on how much light we perceive. Melatonin is a hormone that's produced when we're sleeping, and the body uses light levels to know when it's daytime and when it's nighttime.
As people age, Bachner says they spend less time outside and more time inside, where it's dark, making it harder for the body to know when it’s time to sleep and when it’s time to be awake. And that affects the amount of melatonin in the system, which regulates our circadian rhythms.
Dementia commonly disturbs sleep/wake cycles and also causes deterioration of cognition, mood and behavioral organization.
The Dutch study looked at 189 residents of 12 assisted care facilities, 87 percent of whom had been diagnosed with dementia, over five years. In all facilities, the lights were brightest between 9 a.m. and 6 p.m., but higher wattage lights were installed in half of the facilities.
The new lighting was about 1,000 lux, a measurement of light output equivalent 93 foot-candles, or about 50 percent more than the illuminance found in many open-office areas. In the other six facilities, indoor lighting produced about 300 lux.
In addition, one group was given 2.5 milligrams of melatonin each evening, while another received a placebo.
According to the report, the higher light levels alone were enough to cause positive effects in the patients. The 1,000-lux lighting reduced cognitive decline by 5 percent, reduced symptoms of depression by 19 percent and reduced physical functional decline by 53 percent.
Of those who took the melatonin, 25 had more uninterrupted sleep, although those who just took melatonin and didn't get exposed to the higher light levels showed more signs of withdrawal and depression. The patients who experienced the higher light levels and took the melatonin increased their sleep efficiency by 3.5 percent, reduced nocturnal restlessness by 9 percent and reduced agitated behavior by 9 percent.
“What they found with this latest research … is the same effect as a class of drugs that they give patients with Alzheimer's,” Bachner explains.
For lighting retailers who sell products to older adults, Bachner advocates selling fixtures that allow for higher light levels. “If you use fluorescent lighting to achieve it… no one in the room is particularly going to notice that there are 100 foot candles of light,” he said.
But, he says, it's important that the higher light levels don't increase glare, which can be especially jarring for older adults.
Also, Bachner says motion controlled lighting system are especially effective for older adults who get up in the middle of the night because they can light the way to the bathroom and prevent older adults from falling.
He adds, however, that nightlights shouldn't be too bright because they can interfere with the person's circadian rhythms, and it’s also difficult for older adults to adjust their eyes to drastically different light levels.
Bachman says by increasing light levels for older adults, lighting retailers can significantly improve people's health.
“Older people need better light,” Bachman says. “The quality of lighting can make a difference in the quality of life for older people.”
