New Delhi, 22 September, 2025: Sleep is often called the brain’s reset button. A good night’s rest refreshes memory, restores energy, and sharpens focus. But what happens when someone continues to feel excessively sleepy during the day, even after getting enough hours of sleep at night? While many dismiss this as a minor issue caused by lifestyle habits, mounting research suggests that persistent daytime sleepiness could be an early warning sign of dementia.
We reached out to Dr K. M. Hassan, Senior Director, Neurology, Max Super Speciality Hospital, Noida. Let’s understand this condition and its symptoms better.
Why Daytime Sleepiness Matters
Most people have experienced drowsiness during the day—after a late-night binge, during stressful weeks, or following the use of sedative medications. These instances are usually temporary and improve once the trigger is addressed. However, excessive daytime sleepiness (EDS) is a different concern altogether.
EDS is defined as the inability to stay awake and alert during major waking episodes of the day, leading to unintended lapses into drowsiness or sleep. People experiencing this condition often nod off while reading, watching TV, or even engaging in conversations.
Research shows that this symptom is not just inconvenient but may indicate changes in brain areas controlling attention, alertness, and memory. Studies link EDS with increased risks of neurodegenerative diseases such as dementia, especially when it becomes chronic.
How Sleep and Brain Health Are Interconnected
The brain requires deep, uninterrupted sleep to perform essential housekeeping functions. During sleep, especially slow-wave (deep) sleep, the brain clears out toxic waste products, including abnormal proteins like beta-amyloid and tau. These proteins, when accumulated excessively, are central to Alzheimer’s disease and related dementias.
When sleep cycles are disrupted, this cleansing process is impaired. Over time, poor sleep quality and abnormal sleep patterns may accelerate the build-up of these proteins, damaging brain regions linked with memory and cognition.
In simpler terms, a tired brain is not just underperforming—it may be under threat.
The Dementia Connection
Dementia is an umbrella term for conditions marked by progressive cognitive decline, such as Alzheimer’s disease, Lewy body dementia, and vascular dementia. While memory loss is the most widely recognized symptom, sleep disturbances are also very common in the early and middle stages of these disorders.
- Disrupted sleep-wake cycles
- Dementia patients often experience fragmented sleep at night, waking up frequently or wandering during late hours.
- To compensate, they become excessively sleepy during the day.
- Neurodegeneration in sleep-related brain regions
- Dementia affects areas like the hypothalamus and brainstem, which regulate circadian rhythms and wakefulness.
- Damage here reduces the ability to stay alert.
- A vicious cycle
- Poor sleep worsens memory and concentration.
- Increased cognitive decline further disrupts sleep.
- This creates a loop where both dementia and sleep issues fuel each other.
A large study published in JAMA Neurology reported that older adults with excessive daytime sleepiness were nearly twice as likely to develop Alzheimer’s disease compared to those without it. This reinforces the idea that daytime drowsiness should not be taken lightly.
Other Medical Conditions That Mimic Dementia
It’s important to note that not all daytime fatigue points to dementia. Several other conditions can cause similar symptoms, including:
- Sleep apnea: Repeated pauses in breathing at night cause oxygen deprivation and poor sleep quality.
- Depression and anxiety: Mental health disorders can significantly affect sleep and energy levels.
- Thyroid imbalances: Both hypo- and hyperthyroidism may cause fatigue and sleepiness.
- Medication side effects: Antihistamines, antidepressants, or sedatives may trigger drowsiness.
- Metabolic disorders: Diabetes or vitamin deficiencies can also sap energy.
Because of these overlaps, self-diagnosis is risky. Only a comprehensive medical evaluation can distinguish between benign sleep issues and early signs of dementia.
When to Seek Medical Help
While everyone feels sleepy once in a while, you should consult a doctor if:
- You regularly doze off during the day despite sleeping at night.
- Drowsiness interferes with work, relationships, or safety (e.g., falling asleep while driving).
- You experience additional symptoms like memory lapses, confusion, mood swings, or disorientation.
- Family members notice unusual sleep patterns or cognitive decline.
Early consultation with a neurologist or sleep specialist can lead to timely diagnosis, lifestyle adjustments, and medical management.
Managing Daytime Sleepiness and Protecting Brain Health
Even if dementia is not the underlying cause, addressing excessive daytime sleepiness is crucial for overall well-being. Here are evidence-based strategies that can help:
1. Practice Good Sleep Hygiene
- Maintain a consistent sleep schedule, going to bed and waking up at the same time daily.
- Create a dark, quiet, and cool sleep environment.
- Avoid screens, caffeine, and heavy meals at least two hours before bedtime.
2. Screen for Sleep Disorders
- If snoring, choking during sleep, or restless nights are frequent, get tested for sleep apnea or restless legs syndrome.
3. Stay Physically Active
- Regular exercise improves sleep quality and boosts brain function.
- Even 30 minutes of brisk walking most days of the week can be beneficial.
4. Prioritise Mental Health
- Seek help for depression, anxiety, or stress.
- Mindfulness and relaxation exercises improve both sleep and cognitive resilience.
5. Eat for Brain Health
- A balanced diet rich in omega-3 fatty acids, antioxidants, and whole grains supports brain function.
- Avoid excessive alcohol and processed foods.
6. Stimulate the Brain
- Engage in mentally stimulating activities like reading, puzzles, or learning new skills.
- Such activities build cognitive reserve, which may delay dementia onset.
The Importance of Early Detection
While there is no cure for dementia, early detection can significantly improve outcomes. Timely diagnosis allows:
- Early lifestyle interventions to slow disease progression.
- Access to new therapies and clinical trials.
- Better planning for healthcare, safety, and caregiving.
- Improved quality of life for both patients and families.
Recognising daytime sleepiness as a red flag provides a valuable window for intervention before memory loss and confusion become severe.
Persistent daytime sleepiness should never be brushed aside as “just being tired.” It may be a subtle but important warning sign of dementia or other underlying medical conditions. While occasional drowsiness is normal, ongoing fatigue that disrupts daily life demands medical attention.
As Dr. K. M. Hassan emphasises, “Your brain is constantly communicating through the way you sleep. Ignoring unusual patterns—especially persistent sleepiness during the day—could mean overlooking the earliest signs of neurological changes.”
By paying attention to these signals, adopting healthy sleep practices, and seeking timely medical care, individuals can protect their cognitive health and improve their long-term quality of life.
