Creator: Help Dementia Editorial Team
Published: 2026-04-02T12:19:33

Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.

Sundowning gets sits at the center of this dementia and brain health question.

Sundowning gets worse around the time change because the sudden shift in light exposure and daily schedule disrupts the internal clock that already struggles in dementia patients. When clocks change—especially during the fall back transition when darkness arrives earlier—people with Alzheimer’s disease or other dementias face compounded confusion. Their body clock expects sunset and dinner at the old times, but the clock on the wall says something different. This mismatch between internal expectations and external reality triggers increased agitation, anxiety, and disorientation.

For caregivers, the weeks surrounding daylight saving time transitions represent a predictable window of heightened behavioral challenges that can be significantly softened through deliberate planning around light exposure, meal timing, and activity scheduling. Between 20 and 45 percent of people with Alzheimer’s disease experience sundowning at some point, and prevalence estimates across all dementia patients range from 1.6 to 66 percent depending on how researchers define the condition. Sundowning manifests as increased confusion, anxiety, agitation, pacing, and hallucinations that worsen as the sun sets—not because darkness itself is inherently threatening, but because the person’s deteriorating cognitive ability struggles to navigate the transition. This article explains why time changes amplify these symptoms and walks through evidence-based strategies caregivers can use to minimize behavioral disruption during the vulnerable weeks when clocks shift.

What Is Sundowning and Why Does It Happen During Time Changes?
The Circadian Disruption Behind Behavioral Escalation
Spring Forward Versus Fall Back—Different Risks for Caregivers
Immediate Actions During the Time Change Week
Establishing Robust Routine Anchors Before and After the Change
Light and Environmental Strategies That Work Year-Round
When Routine and Light Alone Aren’t Enough
Conclusion

What Is Sundowning and Why Does It Happen During Time Changes?

Sundowning is not a disease or diagnosis in itself—it does not appear in the DSM-5 and has no standardized clinical criteria. Rather, it is a cluster of behavioral symptoms: increased confusion, anxiety, agitation, disorientation, and difficulty sleeping that occur or intensify between dusk and bedtime in people with dementia. The underlying mechanism involves both the cognitive decline of dementia and the disruption of the circadian rhythm—the body’s 24-hour internal clock that regulates sleep, hormone release, and alertness. When clocks change, this internal clock falls out of sync with external time, and people with dementia become confused when the time change conflicts with both their body’s expectations and the routines they depend on to navigate daily life.

The spring forward transition (which occurred on March 8, 2026) creates acute sleep disruption: the average person loses approximately 40 minutes of sleep that night, and sleep disturbances can persist for days or weeks afterward. For a dementia patient already struggling with nighttime confusion, an abrupt loss of sleep quality often triggers or worsens sundowning. Similarly, the fall back transition gets darker earlier in the evening, which increases the incidence of sundowning in the fall and winter months anyway—adding the compounding effect of a one-hour schedule shift makes the behavior management challenge significantly steeper. caregivers report noticeably increased nighttime agitation, wandering, and requests for inappropriate meals during these transition weeks.

What Is Sundowning and Why Does It Happen During Time Changes?

The Circadian Disruption Behind Behavioral Escalation

The human brain relies on light-dark cycles to anchor its internal clock. Exposure to bright light in morning hours signals to the body that it is time to be alert; dimming light in the evening triggers the release of melatonin and prepares the body for sleep. In dementia, the brain’s ability to use these cues—and to maintain a stable circadian rhythm even when cues are inconsistent—deteriorates. When daylight saving time shifts occur, the relationship between clock time and natural light becomes misaligned: after spring forward, the sun rises later relative to wall-clock time, meaning the patient’s morning light exposure shifts later, and their body clock drifts. The person’s internal expectations (“I should be eating dinner now,” “It should be getting dark soon”) no longer match external reality, creating profound disorientation.

Crucially, this circadian misalignment cannot be “understood” or reasoned away by someone with cognitive decline. A cognitively intact person can remind themselves, “Oh right, we moved the clocks ahead—that’s why it’s still light at 8 PM.” A person with moderate dementia cannot hold that concept. They only experience the discrepancy between what their body expects and what the world shows them. This sensory mismatch, combined with the natural evening decline in cognitive function that sundowning involves, creates a compounding effect. The first week after a time change is often the most difficult; some sources note that behavioral disruption can persist in muted form for two to four weeks as the circadian rhythm gradually realigns.

Spring Forward Versus Fall Back—Different Risks for Caregivers

The two annual time changes pose different challenges. Spring forward (clocks move ahead one hour in March) causes immediate sleep loss and morning light deprivation. Sunrise occurs an hour later by the clock, so morning light exposure happens at what the body perceives as a later time. This delays the natural wake signal, potentially disrupting the person’s ability to wake at their usual time or making them groggy and disoriented. On the evening of the change, many people with dementia experience acute confusion, restlessness, and difficulty falling asleep at the new clock time, even though their body has not yet adjusted.

Fall back (clocks move back one hour in November) creates a different problem: it gets dark an hour earlier by the clock. Sunset now occurs when the clock reads, say, 5 PM instead of 6 PM. For someone with dementia who already struggles more as darkness falls, this earlier onset of evening triggers sundowning behaviors sooner. Additionally, the fall back transition coincides with the season when natural daylight is already decreasing, so the behavioral impact is often more pronounced and longer-lasting. Caregivers frequently report that fall back is the more disruptive transition because it compounds the natural seasonal worsening of sundowning that occurs in autumn and winter anyway.

Spring Forward Versus Fall Back—Different Risks for Caregivers

Immediate Actions During the Time Change Week

The week surrounding a time change is the moment to implement deliberate, structured adjustments. Begin three to five days before the official change by gradually shifting meal times, activity schedules, and bedtimes by 10 to 15 minutes per day in the direction of the change. If springing forward, move activities slightly earlier each day; if falling back, gradually shift them later. This gentle pre-adjustment allows the person’s routine expectations and circadian rhythm to adapt incrementally rather than experiencing a sudden one-hour jolt. On the day of the change itself, maximize light exposure in the morning and afternoon to reinforce the new circadian timing.

Open curtains, take a walk outdoors if possible, or sit by a window for 20 to 30 minutes during midday or early afternoon. This bright light signals to the body clock what time it “really” is biologically, helping the internal clock adjust faster. Maintain strict consistency in meal times, toileting schedules, and activity timing using the new clock time—even if it feels off to the caregiver initially. The consistency matters more than the absolute time; the brain needs predictable anchors. Avoid scheduling new activities, medical appointments, or challenging transitions during the first week after a time change. If sundowning behaviors escalate despite these measures, document when they occur and discuss patterns with the person’s healthcare provider, as medication adjustments or additional behavioral support may be warranted.

Establishing Robust Routine Anchors Before and After the Change

Beyond the immediate transition week, sustained behavioral stability depends on a predictable daily schedule. People with dementia lose the ability to track time abstractly—they cannot glance at a clock and understand “it’s 3 PM, dinner is in a few hours.” Instead, they navigate using routine cues: the quality of light, mealtime cues, the presence or absence of caregivers, and activity patterns. Establish a consistent wake time, breakfast time, midday activity or outing, lunch time, afternoon activity, dinner time, and bedtime. Use the same times every single day, across weekends and weekdays.

This is more important than the precise times chosen; what matters is that the schedule is stable and predictable. However, if the person has existing sleep issues or wakes extremely early, forcing an earlier wake time to match a new “early bird” schedule can backfire and increase nighttime restlessness. Instead, work with the person’s natural sleep patterns and optimize other routine elements. Difficult or new tasks—a haircut appointment, a change in living arrangement, a doctor visit, introducing a new medication—should be scheduled in the morning or early afternoon whenever possible, never during the afternoon or evening hours when sundowning symptoms are most likely to emerge. This is not negotiable for dementia care: the cognitive resources required to process new information or handle stressful situations are depleted by evening in dementia patients, making late-day challenges far more likely to trigger agitation and confusion.

Establishing Robust Routine Anchors Before and After the Change

Light and Environmental Strategies That Work Year-Round

Light is the most powerful regulator of circadian rhythm and the most practical tool caregivers control. During the evening hours—particularly after the fall back change when darkness arrives earlier—ensure the home is well-lit. Use overhead lights, table lamps, or wall sconces in living and dining areas. Soft, warm lighting is preferable to harsh fluorescents, but adequate brightness matters more than aesthetics. Dim lighting during evening hours worsens both the cognitive decline and the sense of disorientation that triggers sundowning. Conversely, during daylight hours, encourage outdoor time or window sitting.

Even on cloudy days, outdoor or window light is significantly brighter than indoor artificial lighting and provides the circadian signal that regulates the internal clock. For caregivers managing someone in the evening, consider using light therapy lamps—devices that emit bright, broad-spectrum light similar to daylight. Research shows that morning light exposure (2,000 to 10,000 lux for 20 to 60 minutes) can accelerate circadian adjustment and reduce sundowning severity. If the person is resistant to sitting outside or by a window, even modest increases in indoor artificial lighting during daytime hours help. The goal is a marked contrast between daytime (bright) and nighttime (progressively dimmer as bedtime approaches). After the spring forward change, prioritize morning light exposure; after fall back, maintain evening brightness to counteract the earlier darkness.

When Routine and Light Alone Aren’t Enough

For some people with dementia, sundowning persists despite excellent routine consistency and optimized lighting. In these cases, discuss with the person’s neurologist or primary care physician whether medication adjustment might help. There is no specific medication for sundowning—it is not a disease entity—but symptoms like agitation or anxiety may respond to low-dose antianxiety medications, mood stabilizers, or other agents. Timing is important: some medications work best if given in the late afternoon, before sundowning typically emerges.

A healthcare provider can evaluate whether medication is appropriate and monitor for side effects. Beyond medication, non-pharmacological strategies such as structured daytime activity, cognitive engagement, and social interaction reduce behavioral symptoms overall. A person with dementia who has participated in a morning activity program, had meaningful social contact, and maintained consistent meal and sleep times will generally experience less severe sundowning than someone in a sedentary, isolated routine. The weeks surrounding a time change are not the moment to introduce new activities, but once the transition has stabilized, reinforcing a robust daytime routine provides the best long-term behavioral support.

Conclusion

Sundowning worsens during daylight saving time transitions because the sudden shift in clock time and light-dark cycles disrupts the internal clock that people with dementia depend on to navigate daily life. The cognitive decline of dementia prevents them from understanding or reasoning through the time change, leaving them confused and disoriented when their body’s expectations no longer match external reality. Caregivers can minimize behavioral escalation by gradually adjusting routines before the change, maximizing light exposure immediately after, and maintaining strict consistency in meal times and activities using the new clock time.

The most effective approach combines three elements: light (morning and afternoon exposure to counteract the time shift), routine (predictable meal and activity times that anchor the day), and strategic scheduling (avoiding new tasks or stressful transitions during evening hours). For most people with dementia, these behavioral adjustments significantly reduce sundowning severity during the transition weeks. If escalation persists despite excellent routine and lighting practices, a conversation with the person’s healthcare provider about medication or additional support is warranted. The weeks around daylight saving time are predictably challenging, but with intentional preparation, caregivers can guide their loved ones through the transition with less distress.