Alzheimer's Disease: Understanding Sundowning Syndrome

In previous articles, I have discussed challenging behaviors in Alzheimer's disease, such as wandering, that cause families distress and result in the patient being institutionalized and in this article I will address Sundowning syndrome, a behavior concerning disruption of the sleep-wake cycle, one that results in increased confusion, restlessness, agitation, and anxiety"”especially after dusk"”and may continue throughout the night. It has been documented to occur in 20 percent of all patients with Alzheimer's disease, and has been appropriately named sundowning as it coincides with "the sun going down."1 Sundowning syndrome is also known as Sundowner's syndrome. Sundowning can be especially difficult for caregivers as it is, in effect, wandering after dark.

When Does Sundowning Occur?

When I refer to the sleep-wake cycle, I am referring to a patient's circadian rhythm. Circadian rhythmicity is what regulates all of our bodily processes, including body temperature, secretion of hormones, heart rate, and so on, and is controlled by the brain. We see behavioral changes in these patients because Alzheimer's disease causes damage to the brain resulting in brain cell death, and shrinkage of the organ. Most of the behavioral issues concerning this dementia are caused by ongoing changes in the brain (see the FAST scale, which identifies loss of function ). We tend to see sundowning in the Moderately Severe or Mid-stage of this disease, which we call Stage 6 (there are seven distinct stages of Alzheimer's disease). Sundowning syndrome occurs while the patient is still ambulatory. While this behavior is challenging for families and staff, the good news is it tends to peak in this stage and then diminish as Alzheimer's progresses.

What the Experts Say About Sundowning & Circadian Rhythms

In a recent study entitled Sundowning and Circadian Rhythms in Alzheimer's Disease, researchers investigated the relationship between sundowning and circadian rhythms. They concluded that while behavioral symptoms associated with dementia can occur at any time of day, Alzheimer's disease caused disturbances of circadian rhythms; and, sundowning was related to a phase delay in body temperature that was a result of the disease process.2 The authors point out therapeutic goals for sleep disturbances, such as respiratory problems like sleep apnea, differ from those used to treat sundowning, where the emphasis is on patient safety and comfort rather than sedation and sleep. For that reason, they conclude the term "sundowning" should be associated with behavioral disturbances that occur during the late afternoon and evening hours when the patient is expected to be awake.

Further, the authors caution that this population is difficult to accurately study as many patients with Alzheimer's disease are hospitalized during the later stages—which contributes to changes in circadian rhythms—or, have other comorbidities that affect their sleep. For families and caregivers or institutions, it is important to keep in mind that each patient is individual and their needs (and behaviors) should be addressed on that basis.

Suspected Causes of Sundowning

There are identified triggers that tend to precede sundowning behavior, although there is not consensus on actually why the patients react to the triggers. Most behaviors are attributed to the following factors:

  • End-of-day (afternoon) confusion or exhaustion
  • Disturbance in the "biological clock" (this is the circadian rhythm)
  • Decreased ability to handle stress
  • Poorly lit rooms and increased shadows (coupled with possibly poor eyesight)
  • Difficulty differentiating dreams from reality
  • Restlessness due to boredom
  • Decreased need for sleep (common in older adults)
  • Caregiver communicated fatigue

I often tell families that being a caregiver may be the most important job they will undertake in their entire lifetime. Taking care of themselves will allow them to have the energy to care for their loved one. Learning what to expect and what is expected can help them feel more comfortable in this new role. (And, if their loved one is now institutionalized, the "caregiver" role does not just go away. In fact, it can be confused with the guilt often felt when families can no longer care for the patient at home.) If hospice care is involved by this point, the hospice team will provide teaching about the disease process so the family can feel confident when giving care, as well as addressing the psychological and social needs of the patient and family. If the patient is institutionalized, hospice will support the facility in identifying stages and what changes to expect—and communicate these changes to the family.

Coping with Sundowning Behavior

The following suggestions can help keep the Alzheimer's patient safe, and reduce anxiety. Try to maintain a structured routine that provides activities within the patient's coping ability, as well as applying the following tips to cope with sundowning behavior.

  • Plan activities for earlier in the day, rather than in the afternoon, to avoid exhaustion.
  • Discourage daytime napping and encourage exercise such as taking a walk to use extra energy and promote sense of well-being.
  • Take special notice of the patient's diet—limit caffeine and sweets to early in the day to reduce sleeplessness and agitation.
  • Monitor noise levels from televisions, radios, or stereos to decrease agitation.
  • Keep sleeping room partially lit to prevent patient from becoming disoriented.
  • Caregivers should remember to take care of themselves to avoid transferring stress.1

We can better accept the changes that occur in the Alzheimer's patient if we understand the changes that occur in the brain. Confusion, restlessness and agitation occur because the brain can no longer sort out clues in the patient's environment. As Alzheimer's disease progresses, more and more nerve cells or neurons (we normally have about 100 billion!) in the brain die, resulting in brain shrinkage. This "shrinking" equates to losses in functional ability. The FAST scale helps illustrate for families and caregivers or institutions, the expected losses at each stage. Sundowning occurs in Stage 6, so beside the disruption of the sleep-wake cycle, the patient may begin to exhibit suspiciousness concerning his or her surroundings, delusions regarding the caregiver as really being an "imposter" and repetitive behaviors. So, too, this is the stage in which we begin to see wandering behavior.

Understanding what triggers sundowning, taking steps to reduce those triggers, and realizing the main goal should always be safety for the patient, helps us all cope better when caring for the Alzheimer's patient. And, knowing what to expect as Alzheimer's disease progresses and sundowning behaviors occur, receiving the necessary support along the way, will make this road a little easier to navigate—for family and caregivers alike.

Celebrating Life!

Audrey Wuerl

1Alzheimer's Association. 2007. Sleeplessness and Sundowning, pp. 1–2. Accessed May 4, 2009
2Volicer, L, Harper, D, Manning, B.C., Goldstein, R. and Satlin, A. (2001, May). Sundowning and Circadian Rhythms in Alzheimer’s Disease. American Journal of Psychiatry, 158:5, pp. 704–711

Audrey Wuerl

Audrey Wuerl, RN, BSN, CHPN, is education coordinator for Hospice of San Joaquin in California, which serves San Joaquin County and its surrounding areas. See full bio