# Can Poor Sleep Hygiene Increase Dementia Likelihood?
Sleep is far more than just rest. When you close your eyes at night, your brain is actively working to consolidate memories, remove harmful waste products, and regulate emotions. Poor sleep hygiene disrupts these critical processes, and research increasingly shows that chronic sleep problems may significantly raise your risk of developing dementia.
## How Sleep Protects Your Brain
During deep sleep, your brain activates a cleaning system called the glymphatic system. This system clears out toxic proteins, particularly beta-amyloid and tau tangles, which are the hallmark markers of Alzheimer’s disease. When you sleep poorly or not enough, these harmful proteins accumulate in your brain tissue over time. This buildup triggers inflammation, oxidative stress, and damage to brain cells, accelerating the process of neurodegeneration.
The connection between sleep quality and brain health is so strong that researchers have found a clear pattern: people who consistently get inadequate sleep show cognitive decline that resembles the deterioration associated with aging, one of the strongest risk factors for Alzheimer’s disease.
## What the Research Shows
A major study published in the American Journal of Preventive Medicine examined over 6,000 adults aged 65 and older over a 10-year period. The findings were striking. People who struggled with sleep initiation insomnia, which is difficulty falling asleep, had their dementia risk increased by just over 50 percent. Additionally, those who regularly used sleep medications showed a 30 percent increased risk of developing dementia.
The research also revealed something unexpected about sleep duration. While health organizations typically recommend 7 to 9 hours of sleep per night, one study found that both sleeping too little and sleeping too much posed risks. Adults sleeping less than 4.5 hours per night and those sleeping more than 6.5 hours showed greater cognitive decline over time. However, researchers emphasized that the real issue may not be the clock but rather the quality of sleep itself. All participants in that study struggled with poor sleep quality regardless of how long they slept.
## The Mechanisms Behind the Connection
Poor sleep affects your brain in multiple ways. Chronic insomnia raises stress hormone levels, damages neurons, and disrupts your circadian rhythm, the internal clock that regulates sleep-wake cycles. Sleep apnea, a condition where breathing repeatedly stops during sleep, reduces oxygen supply to the brain and can cause permanent cognitive impairment if left untreated.
For people already showing signs of mild cognitive impairment, the stakes are even higher. Research shows that 60 to 70 percent of people with mild cognitive impairment experience sleep disturbances, compared to only 35 to 37 percent of cognitively healthy older adults. When poor sleep quality persists for more than two years in this population, the risk of hippocampal atrophy and abnormal beta-amyloid accumulation increases dramatically, accelerating the progression from mild cognitive impairment to dementia by approximately threefold.
## The Bigger Picture
Sleep is just one piece of the dementia prevention puzzle. Research from the UK Biobank involving middle-aged and older adults found that a combination of healthy factors working together provides the strongest protection. These factors include meeting physical activity recommendations, maintaining grip strength above the median for your sex, sleeping 7 to 8 hours per day, and spending less than 6 hours per day being sedentary. When people adopted all of these healthy habits together, they showed substantially lower dementia risk than those who focused on just one factor.
Scientists are careful to note that good sleep is not a cure or magic shield against dementia. People with excellent sleep habits can still develop the disease, and many other factors contribute to dementia risk, including genetics, cardiovascular health, cognitive engagement, and social connection.
## What This Means for You
If you struggle with insomnia or poor sleep quality, it is worth taking seriously. Experts recommend talking to your doctor if insomnia is persistent. They can help identify underlying causes and discuss treatment options. Improving sleep hygiene, which includes maintaining a consistent sleep schedule, keeping your bedroom cool and dark, and avoiding screens before bed, may help. Some people benefit from cognitive behavioral therapy for insomnia, which is a structured approach to addressing sleep problems.
The research is clear: your sleep habits today may influence your brain health for decades to come. By prioritizing quality sleep as part of a broader healthy lifestyle, you are taking an important step toward protecting your cognitive future.
## Sources
https://www.sparshhospital.com/blog/sleep-and-brain-health-alzheimers-risk/
https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1693052/full
