Sleep loss and Alzheimer’s, the neurodegenerative danger of chronic insomnia, and why good sleep is important

Sleep benefits: The absence of sleep can have a long-term cost on memory, emotion, and cognition (Image: Canva)

Going to bed with your mobile phone, staying up late scrolling through reels, catching up on office work, or simply lying awake has become the norm for many. In today’s sleep-deprived culture, insomnia is often brushed off as a minor inconvenience, but experts say otherwise.

So, if you think missing sleep is harmless, think again. Research shows that sleep deprivation may actually fuel Alzheimer’s by disrupting the brain’s natural repair process.

Sleep is the brain’s repair mode, says Dr Aparna Gupta, Associate Director, Neurology, Indian Spinal Injuries Centre, Vasant Kunj. “The absence of sleep can have a long-term cost on memory, emotion, and cognition. In fact, sleep deprivation doesn’t just worsen symptoms of Alzheimer’s, growing research suggests it could play a role in its onset,” she says.

Also read | How to sleep better: 9 healthy habits to prevent insomnia, sleep apnoea, promote overall well-being

Insomnia, the chronic inability to sleep or stay asleep, does more than ruin your mornings. It disrupts the glymphatic system, the brain’s built-in detox network, which is most active during deep sleep. “Without proper rest, neurotoxic waste like beta-amyloid proteins accumulate, which are closely associated with Alzheimer’s pathology. Poor sleep impairs memory retention and fuels anxiety and depression, both of which independently increase cognitive decline. The connection between sleeplessness and Alzheimer’s is biological. And breaking the cycle starts with recognising insomnia as more than fatigue. It’s a red flag for the brain,” says Dr Gupta.

Alzheimer’s is progressive, but it rarely begins abruptly. “Early signs often show as everyday forgetfulness. These can include struggling with vocabulary, forgetting appointments, or misplacing familiar objects. Over time, cognitive challenges escalate: simple decisions become confusing, multitasking feels overwhelming, and once-routine tasks like cooking or driving become distressing,” cautions Dr Gupta.

Mood changes, irritability, withdrawal, even sudden anger, can also signal the onset of dementia. “Insomnia may not be the sole cause, but it magnifies every symptom. That’s why addressing sleep early with therapy, sleep hygiene, or stress regulation, can be a powerful tool in Alzheimer’s prevention,” she explains.

Also read | Health benefits of sleep: Deep, restorative sleep matters more than hours spent in bed

Dr Gupta reveals signs your brain may be sleep-deprived and not just tired:

• You forget more than usual: Early memory lapses, especially with names or appointments, are common in both insomnia and early Alzheimer’s.
• You struggle with basic problem-solving: When you can’t follow a recipe or balance your budget like you used to, your executive function might be compromised.
• You feel emotionally erratic: Irritability, depression, or apathy may be signs of early cognitive decline worsened by poor sleep patterns.
• You’re less socially active: Social withdrawal and a drop in interest in hobbies or people are often early red flags, especially when linked to sleep issues.
• You often make poor decisions: If small tasks now feel complex or risky choices seem “normal,” your brain may be struggling with impaired judgement from chronic insomnia.