Sundowning typically starts in the late afternoon, often between 4:00 and 6:00 p.m., as daylight begins to fade. Symptoms can then persist well into the night. The exact timing varies from person to person and can shift with the seasons, since shorter winter days mean earlier darkness and potentially earlier onset.
Sundowning, sometimes called sundown syndrome, is a pattern of increased confusion, agitation, and restlessness that affects people with dementia or Alzheimer’s disease. The Alzheimer’s Association estimates that up to 20% of people diagnosed with Alzheimer’s experience it, though some studies of community-dwelling patients have found rates as high as 66%, depending on how the condition is defined and measured.
Why Late Afternoon Triggers Symptoms
The link between fading daylight and worsening symptoms isn’t just coincidence. The brain relies on light cues to synchronize its internal clock with the external world, regulating when you feel alert and when you feel sleepy. In people with dementia, this system is often damaged, making it harder for the brain to translate the shift from light to dark into a smooth transition toward evening rest. Instead, the dimming light triggers confusion and distress.
Melatonin, the hormone your body releases in response to darkness to help initiate sleep, plays a central role. Older adults naturally produce less melatonin than younger people, and those with dementia often produce even less. This deficiency disrupts the normal sleep-wake cycle, which can worsen behavioral symptoms in the evening hours. Essentially, the brain receives the signal that darkness is coming but lacks the chemical machinery to respond in an orderly way.
Fatigue compounds the problem. By late afternoon, a full day of navigating a world that already feels confusing has taken its toll. Being overtired increases restlessness and irritability, which is why sundowning tends to be worse on days that were especially busy or stimulating.
What Sundowning Looks Like
Sundowning isn’t a single behavior. It’s a cluster of changes that can look quite different from one person to the next. Common physical behaviors include pacing, rocking in a chair, wandering, crying, and yelling. Some people become violent. Others begin “shadowing,” which means following their caregiver closely from room to room, unwilling to let them out of sight.
Emotionally, a person who was relatively calm during the day may suddenly seem anxious, fearful, sad, or deeply irritable. The shift can feel abrupt. In more severe episodes, sundowning can bring on paranoia, delusions, or hallucinations, making the person believe things are happening that aren’t real. Insomnia often follows, extending the difficult period well past bedtime.
If you’re caring for someone with dementia and notice a predictable late-afternoon change in mood or behavior, that pattern itself is the clearest sign of sundowning. It’s distinct from the general confusion of dementia because of its timing: things are noticeably worse as the day winds down.
Environmental Factors That Make It Worse
The physical environment matters more than many caregivers realize. As the sun sets, indoor lighting creates uneven shadows that can be disorienting or even frightening to someone with dementia. Reflective surfaces like mirrors, glass doors, or polished floors can add to the confusion, producing visual effects the person can’t make sense of. Closing curtains or blinds as it starts to get dark removes the visual cue of fading light and eliminates some of those disturbing reflections.
Hunger, pain, and other unmet physical needs also act as triggers. A person with dementia may not be able to articulate that they’re uncomfortable, so the discomfort comes out as agitation instead. Checking in on basics like whether they’ve eaten enough, whether they need the bathroom, or whether something hurts can sometimes head off an episode before it escalates.
Reducing the Severity of Episodes
There’s no way to eliminate sundowning entirely, but several strategies can soften its impact. Most center on stabilizing the body’s internal clock and reducing late-day stress.
- Maintain a consistent daily routine. Predictability helps compensate for the brain’s weakened ability to track time. Meals, activities, and bedtime at the same hours each day provide external structure the internal clock can no longer supply on its own.
- Prioritize daylight exposure. Spending time outside or sitting by a bright window during the morning and early afternoon helps reinforce the brain’s sense of day versus night. Bright light therapy using a 10,000-lux lamp for 30 to 90 minutes in the morning can serve the same purpose when outdoor time isn’t practical.
- Keep the person active earlier in the day. Physical activity during morning and early afternoon hours helps reduce restlessness later, but too many activities or overstimulation can backfire by increasing fatigue.
- Cut caffeine and alcohol after midday. Coffee, cola, and alcoholic drinks consumed in the afternoon or evening can interfere with sleep onset and amplify agitation during the sundowning window.
- Limit late-day napping. Long naps or dozing in the late afternoon can push the sleep-wake cycle further out of alignment, making evening confusion worse.
Why Timing Varies Between People
Not everyone’s sundowning starts at the same hour. Several factors influence the exact timing. Geographic location and season affect when daylight fades, so a person living in northern latitudes during winter may start showing symptoms earlier than someone in a southern climate. Individual sleep patterns matter too: someone who wakes very early may hit their fatigue threshold sooner in the afternoon.
The stage of dementia also plays a role. As the disease progresses and more of the brain’s timekeeping circuitry deteriorates, the onset window can shift or expand. Some caregivers report that episodes gradually begin earlier in the day over months or years. Tracking the pattern in a simple log, noting the time symptoms start and what happened in the hours before, can help you and a healthcare provider identify individual triggers and adjust the daily routine accordingly.