What’s behind Sundowning? Part 1

When my mother was living with me, her Alzheimer’s was fairly advanced and she had begun to be fearful after dark. One evening, she came to me, trembling.

“There’s a strange woman outside, trying to get in my window!” she said. 

I went with her to see. With the light on inside and the window shade up in her room, as she approached the window, she saw her own reflection in the glass. 

“See? There she is!”

There was no point in disputing her interpretation of the reflection. She didn’t need facts: she needed reassurance. So I said, “I’ll make her go away for good,” and pulled down the shade. 

Then I distracted her with some ice cream. From that time on, I made sure her shades were always down when it started to get dark.

Alzheimer’s can cause disorientation and changes in vision. That creates anxiety and may lead people with the disease to misinterpret reflections, just as my mother did.

Her behavior had begun to change in other ways in the late afternoon. Always a somewhat anxious woman, she now sometimes became agitated very rapidly over what seemed slight matters. Three weeks before Christmas, she suddenly thought of Christmas cards at 5:00 in the afternoon. Nothing would calm her until I sat down with her and addressed 20 envelopes and explained repeatedly that yes, she had signed the cards that were inside.

The increased, and often acute, distress that people with dementia of any kind can feel in the late afternoon and evening is commonly called “sundowning.” It is a phenomenon well known to family caregivers and the staffs of nursing homes, but it has yet to be subjected to rigorous study. 

In part, that’s because researchers can’t agree on its definition—which behaviors should qualify as sundowning and in what time frame they should occur. Without an agreed-on definition, it’s hard to set criteria for diagnosis, and that, in turn, makes it hard to get conclusive scientific results. 

Nevertheless, there is wide agreement on two very likely contributors to sundowning: disrupted circadian rhythms and environmental stress. Knowing that much can guide us to make sundowning less likely to happen and often, to mitigate it when it does.

This blog will be about the ways disrupted circadian rhythms contribute to sundowning. My next blog (What’s behind Sundowning? Part 2) will be about the contributions made by environmental stress. 

Circadian rhythms are the daily cycles that body processes go through, not just in human beings but in all living things. In humans, physiological functions, such as body temperature, blood pressure and the sleep-wake rhythm, wax and wane during the day in sync with the 24-hour cycle of daylight and darkness. 

A group of special cells in the brain’s hypothalamus form a kind of master clock that coordinates everything. Those brain cells receive information from the retina about your exposure to light, and as daylight fades, they trigger the release of a hormone called melatonin, which promotes sleep and has a role in regulating behavior. Other brain cells are influenced in the opposite way: at break of dawn, they trigger the release of the hormone cortisol, which energizes us during the day. 

A brain with dementia loses neurons in that master-clock region, and its levels of melatonin are lower overall. If the body’s synchronizer is damaged, it seems logical that the coordination of cycles must suffer. Many researchers feel sundowning results from that.

Often compounding the problem, diseases of older eyes, such as cataracts, glaucoma and macular degeneration, can make it hard for adequate light to reach the retina to trigger the phases of the daily cycle. 

Sundown is normally a critical turning point in this cycle. My good friend Phil unexpectedly discovered the stark difference time of day can make. He faithfully visited his mother at a nursing home every day after he got home from work. She had dementia and over the past year had become more anxious, asking repeatedly to go “home to Iowa,” where she grew up. He assumed this anxiety was her new normal.

After he retired, Phil switched to visiting his mother at lunchtime. She was delighted to see him and, though forgetful, she was content. He asked the nurse what drug had brought about this change. 

“Oh, she’s always like this—until five o’clock,” the nurse told him.

Sometimes the restlessness and anxiety of sundowning last long after darkness falls and keep people with Alzheimer’s—and you, their caregiver—awake half the night. 

Because light is of primary importance in resetting a circadian rhythm gone awry, addressing sundowning with light exposure seems a safe and sensible approach. No prescription needed, and it can be effective. 

Take your loved one outside in bright, morning sunlight. Take a walk or do whatever he (or she) is capable of for at least an hour. The more time he can spend outdoors in morning light, the more wide-awake he should be all day and the better his mood may be. If you can’t get him outdoors, seat him beside a sunny window for an hour or more. 

You can also provide indoor lighting that more closely matches what’s outdoors. Look for LED bulbs that say they’re equivalent to 75 watts and are daylight white. Use them in the room where he spends the most time. The package should also say “1100 lumens,” another measure of the bulb’s light output. Be sure to get daylight white LED bulbs because others won’t have enough of the blue-wavelength light that is especially effective in telling the brain to suppress melatonin. The bulb’s K number will also be on the package. That’s a measure of how cool the color of the light is, and daylight white bulbs are 5000K. 

By the same token, you don’t want to use such bright bulbs in the late afternoon and evening. Then it’s time to signal the brain to release melatonin and bring about sleep. Either dim the lights or turn off the high-lumen, daylight white bulbs and turn on lamps that have warm (or ”soft”) white bulbs, and that are equivalent to 60 watts, 800 lumens, 2700K. These should promote the evening release of melatonin.

Because electronic screens (computer monitors, tablets or smart phones) emit large amounts of blue-wavelength light, it’s good to steer your loved one away from viewing them in the evening. Or you can buy red filters for the screens.

Melatonin is available as an over-the-counter supplement, and you may be tempted to try it if light exposure doesn’t work to reduce sundowning or sleep disturbance. Some studies show that melatonin helps, while others show no effect. First, get your doctor’s advice about a reliable brand, any contraindications for its use for your loved one and the correct dosage.

Therapeutic, full-spectrum light boxes, used to treat seasonal affective disorders, are generally useless for people with dementia. You need to be motivated to sit still facing them for at least an hour, and not many people with dementia can focus and remain motivated that long or understand why they should do it.

Several caregivers have told me that their loved one’s circadian rhythm is messed up in a different way. As Nancy put it, “My husband insists on going to bed at 5:30 p.m. and nothing I do can stop him. Then he’s awake at 3:30 a.m.!”

The solution to try in those cases is exposure to sunlight in midafternoon to suppress the release of sleep-inducing melatonin until later in the evening. And make sure the person’s day has periods of quiet time, interspersed with more active periods, so that she (or he) doesn’t get overtired.

Resetting the circadian rhythm to a more normal pattern is the first step to reducing sundowning. It sets the stage for the equally important second step: changing the elements of the environment that unduly challenge someone with cognitive disease. I’ll address the relationship between the environment and sundowning in my next blog.