15 Causes of Sundowning Syndrome

2. Lack of Exercise

Limited physical activity can affect both the body and mind, especially for people who spend much of the day sitting or staying indoors. Low activity levels are often linked to reduced energy, poorer sleep quality, and increased stress. In people with dementia, this lack of movement can contribute to confusion and restlessness, which often become more noticeable in the evening.

Regular movement supports healthy blood flow to the brain and helps regulate mood. When exercise is limited, the balance of hormones that support calmness and alertness may be disrupted. This can increase feelings of agitation, anxiety, or frustration as daylight fades. Even gentle activities such as walking, stretching, or gardening can help stabilize mood and support clearer thinking.

Physical activity also plays an important role in sleep quality. A person who does not move enough during the day may struggle to fall asleep or stay asleep at night. Poor sleep can build up over time and increase the likelihood of late-day confusion and irritability commonly associated with sundowning.

3. Poor Eating Patterns

Poor eating patterns can increase the risk of sundowning in people with dementia. Irregular meals or eating too little may cause drops in blood sugar, which can lead to confusion, irritability, and fatigue that become more noticeable later in the day.

Over time, poor nutrition can also affect overall health and brain function. Diets lacking key nutrients such as protein, vitamins, and minerals may weaken the body and make it harder to stay alert or cope with stress. This gradual decline can increase vulnerability to stronger sundowning symptoms in the evening.

Large or heavy meals close to bedtime can cause discomfort and disrupt sleep. Foods high in sugar and drinks containing caffeine can interfere with the body’s natural sleep–wake rhythm, often causing short energy spikes followed by crashes.

4. Stress

Stress is a common trigger that can worsen sundowning symptoms. Ongoing mental or physical strain causes the body to release stress hormones that keep a person overly alert. In someone with dementia, this often appears as increased confusion, agitation, or restlessness later in the day when energy levels are low.

Stress can build gradually throughout the day. Daily worries, noisy environments, and unexpected changes create emotional pressure that becomes harder to manage as evening approaches. Fatigue and reduced light can further strain the brain’s ability to process information, which increases anxiety and disorientation.

Long-term stress also affects sleep, mood, and concentration. Poor sleep reduces the brain’s ability to cope with everyday demands, which can intensify evening confusion. Caregivers may notice that even small disruptions, such as a change in routine or misplacing an item, can quickly trigger agitation.

5. Lack of Familiarity

Lack of familiarity often plays a major role in triggering sundowning symptoms. When a person with dementia moves to a new home, hospital, or care facility, unfamiliar surroundings can increase confusion. New room layouts, furniture, and lighting may be difficult to recognize, which can raise stress levels, especially in the evening.

Even smaller changes, such as rearranging furniture or having a different caregiver, can cause anxiety. Familiar routines and personal belongings help provide a sense of safety and stability. When these comforts are missing, the person may become restless or agitated as they try to make sense of their environment.

Evening conditions can intensify this effect. As light fades, shadows become more noticeable and spaces can feel less recognizable. Using bright, consistent lighting can help reduce confusion during this time. Keeping familiar items like family photos, favorite blankets, or meaningful objects close by can also support comfort and orientation.

6. Lack of Routine

A regular daily routine provides structure and predictability for people living with dementia. Consistent patterns for waking, meals, activities, and bedtime help guide the person through the day and support the body’s internal clock.

When this structure is missing, the sleep–wake cycle can become disrupted. Irregular bedtimes, frequent daytime naps, skipped meals, or sudden changes such as new caregivers or unfamiliar environments can feel unsettling. These disruptions often lead to increased confusion and anxiety, especially as evening approaches.

As daylight fades, many people experience greater disorientation, restlessness, and mood changes. In simple terms, routine brings stability. When that stability breaks down, a person’s sense of time and place can weaken, making evenings more challenging for both the individual with dementia and those who support them.

7. Poor Condition

Poor physical health can worsen sundowning symptoms. When the body is affected by illness, infection, or ongoing pain, it places extra strain on both physical and mental functioning. Fatigue and discomfort can make it harder for a person to stay calm and focused, which often leads to stronger confusion and agitation in the evening.

Unmanaged health conditions can also trigger stress responses in the body. Issues such as dehydration, low oxygen levels, or changes in blood sugar may increase disorientation. Even mild problems, including colds or urinary infections, can cause noticeable changes in mood or behavior in older adults with dementia and may contribute to sudden worsening of sundowning symptoms.

General weakness can further affect daily rhythms. Poor nutrition, limited movement, or extended periods of rest can reduce energy and disrupt the sleep–wake cycle. When the body does not get enough stimulation during the day, restlessness and irritability are more likely to develop at night.

Certain health problems are closely linked to specific behavior changes. Infections may increase confusion and restlessness. Dehydration can lead to fatigue and irritability. Poor nutrition can lower energy and concentration, while chronic pain often triggers mood changes and agitation.

8. Other Causes

Sundowning can also be influenced by several everyday factors that affect comfort and routine. Environmental changes such as shifts in lighting or increased noise levels during the evening may raise confusion and restlessness, especially when surroundings feel overstimulating.

Sleep disruption is another common contributor. Many people with dementia experience changes in their sleep–wake cycle, which can lead to excessive daytime napping and difficulty sleeping at night. Poor sleep often builds throughout the day and can intensify confusion and irritability by evening.

Some medications and underlying health conditions may further contribute to sundowning. Medicines that affect the nervous system or cause drowsiness can increase disorientation in the evening. Physical discomfort from pain, infection, or constipation may also lead to frustration that becomes more noticeable at night.

Changes in routine, such as moving to a new environment or altering daily activities, can feel unsettling for a person with dementia. Predictable schedules tend to provide comfort and stability. When routines are disrupted, confusion and agitation are more likely to increase during the late afternoon and evening.

9. End-of-Day Activity Anxiety

End-of-day activity anxiety often appears as evening approaches and routines begin to shift. Transitions such as finishing daytime tasks, preparing meals, or getting ready for bed can feel confusing for people with dementia. These changes may lead to restlessness or a sense of being overwhelmed.

Environmental stimulation can intensify this anxiety. Busy settings with noise, visitors, or frequent movement may increase agitation. Even small changes, like turning on lights, clearing the table, or having a different caregiver, can create uncertainty about what will happen next.

Physical needs can also contribute. Fatigue, hunger, or the need to use the toilet may reduce a person’s ability to stay calm. As light fades, shadows and lower visibility can further increase confusion or fear. Many caregivers find that creating a calmer environment in the late afternoon and evening helps reduce anxiety.

10. Too Much Screen Time

Too much screen time can interfere with the body’s natural sleep–wake rhythm and may worsen sundowning symptoms in people with dementia. Bright light from televisions, tablets, and phones in the evening can suppress the release of melatonin, the hormone that helps the body prepare for sleep.

When this process is disrupted, confusion, agitation, and restlessness often become more noticeable later in the day. These changes may show up as difficulty settling down at night, increased irritability or confusion in the evening, and a shorter attention span with higher anxiety levels.

Spending long hours in front of screens can also reduce physical movement and social interaction. Limited activity during the day can contribute to poorer sleep quality, while reduced engagement with others may increase feelings of isolation.

11. Dementia

Dementia is one of the main underlying causes of sundowning because it changes how the brain processes information. These changes often lead to memory loss, confusion, and difficulty thinking clearly. Over time, it can become harder for a person to recognize time, place, and surroundings, especially when lighting and environmental cues begin to shift.

As evening approaches and daylight fades, disorientation often increases. This can trigger restlessness, anxiety, or agitation. The transition from day to night may make a person feel unsafe or unsure of their environment, which can lead to behaviors such as pacing or wandering. The likelihood of sundowning often rises as dementia progresses. It tends to appear more frequently in people living in care facilities or in those who have recently experienced changes, such as moving to a new room or environment.

12. Alzheimer’s Disease

Alzheimer’s disease is the most common form of dementia. It causes gradual changes in memory, thinking, and reasoning. As brain cells become damaged by abnormal protein build-up, a person may begin to struggle with everyday tasks and have difficulty recognizing familiar people and surroundings.

Sundowning becomes more common as Alzheimer’s progresses. Many people experience increased confusion, agitation, or restlessness in the late afternoon or evening. This happens in part because the brain’s internal clock becomes disrupted, making it harder to distinguish between day and night. Proteins called amyloid and tau can form clusters that interfere with communication between brain cells.

As more cells are affected, control over mood, behavior, and thinking may decline. Mental fatigue that builds up throughout the day can further intensify confusion by evening. Environmental factors such as dim lighting, shadows, and increased noise in the evening can worsen symptoms by triggering frustration or anxiety.

13. Seasonal Affective Disorder

Seasonal Affective Disorder (SAD) is a type of depression that follows a seasonal pattern. It most often appears in late fall and winter and usually improves during spring and summer when daylight increases. In some cases, it can occur during warmer months, but this is less common.

Reduced exposure to daylight can disrupt the body’s internal clock and affect brain chemicals that regulate mood. These changes may lead to low energy, difficulty concentrating, and shifts in sleep and appetite. Shorter days can also make it harder to stay motivated and emotionally balanced. People with SAD commonly experience persistent low mood, loss of interest in usual activities, increased sleep, overeating, and social withdrawal.

14. Lack of Emotional Control

People with dementia may struggle to regulate their emotions, especially as the day goes on. Mental fatigue and overstimulation can make it harder to stay calm or think clearly. This loss of emotional control often becomes more noticeable in the late afternoon or evening, which can intensify sundowning symptoms.

Emotional shifts may occur quickly. A person can move from calm to upset or anxious within a short time. These sudden changes may lead to behaviors such as crying, shouting, or pacing. Because dementia affects memory and judgment, the person may not understand why these feelings occur, which can increase frustration.

Fatigue, hunger, loud noise, and unfamiliar surroundings are common triggers. Changes in lighting and the appearance of shadows can also increase confusion or fear. Caregivers often find that consistent routines and reducing clutter help limit these reactions.

15. Improper Medication

Improper use of medication can worsen sundowning symptoms in people with dementia. Taking the wrong dose, missing doses, or changing the timing of medicines can disrupt the body’s natural rhythm. This disruption can increase confusion, restlessness, and agitation, especially in the evening.

Some medications can also directly contribute to late-day symptoms. Drugs that affect mood, sleep, or alertness may cause drowsiness at first, followed by irritability or disorientation as their effects wear off. Medications that strongly affect blood pressure can sometimes interfere with mental clarity as well. Medication-related problems are more common in older adults because many take multiple prescriptions at the same time.