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The Link Between Sleep and Early Memory Loss

Is good sleep a distant memory these days?

Life is busy and stressful at times, so it can be difficult to get your eight hours of sleep at night. Add in insomnia, sleep apnea or another sleep issue, and you may be getting even less quality sleep. Without a proper night’s rest, it can leave you feeling drowsy, grumpy and forgetful.

We all have times of forgetfulness when we’re sleep-deprived. Usually, these short-term memory blips get better with a good night’s rest, but poor sleep can also have lasting effects on your memory, namely cognition.

“Cognition is a range of mental processes involved in gaining knowledge and comprehension,” said Jessica Langbaum, PhD, director of the Alzheimer’s Prevention Initiative at the Banner Alzheimer’s Institute in Phoenix, AZ. “Some of the many processes include thinking, knowing, remembering, language, problem solving and perception.”

Several recent studies have linked poor sleep with a decline in cognitive functioning, including the development of mild cognitive impairment, Alzheimer’s disease and dementia.

Thankfully, there is also evidence that improving sleep can boost short- and long-term cognitive performance.

If you’re wondering if you or a loved one should see someone about memory loss, Dr. Langbaum shared what you should know.

How does sleep affect our brains?

Sleep is an important time for your brain to form and consolidate memories and do other housekeeping things for itself and the body to recharge.

During sleep, your brain waves become slower. Meanwhile, different chemicals and systems of the brain become activated or deactivated, sending you through different stages of sleep to coordinate your rest and recovery.

Poor sleep, whether due to quantity or quality, can make it difficult for your brain to progress through these sleep cycles in a normal, healthy way.

“Too little sleep or inadequate sleep on a regular basis means the brain isn’t able to encode, consolidate and reconsolidate memories,” Dr. Langbaum said. “Numerous studies have found that loss of sleep also impairs attention and executive functions, like focus and planning, and increases the frequency of cognitive complaints in middle-aged adults.”

What are the short and long-term effects of poor sleep on cognition?

In the short-term, not getting proper sleep can cause many of the daytime effects you’re familiar with, such as sleepiness, fogginess and moodiness. You typically forget things you’ve done recently, such as where you placed your keys or phone, or information just shared with you.

“The following day, you may be prone to making more errors, have a slower reaction time and make riskier choices,” Dr. Langbaum said. “As a result, it can harm your intellectual and academic performance, productivity and create health risks, such as the dangers from drowsy driving.”

While the short-term effects of poor sleep may be felt immediately and be more apparent, there are risks that can affect your cognition in the long run.

“Studies have found that during sleep, the glymphatic system is most active,” Dr. Langbaum said. “This system is the ‘housekeeping’ service for our central nervous system, clearing out the brain of metabolic waste products that can be harmful if they aren’t eliminated.”

Some of this waste includes potentially toxic proteins like amyloid beta. When this protein builds up or clumps together and doesn’t get flushed out, it forms plaque in the brain. Beta amyloid plaques play a key role in memory loss and other cognitive impairments and are a key feature of those with mild cognitive impairment and Alzheimer’s disease.

“Studies have found that people who get too little sleep (less than six hours a night on a regular basis) have more amyloid plaques in their brains,” Dr. Langbaum said. “This is one possible explanation for cognitive decline and dementia, but further research is needed.”

Should I be worried if I sleep too much?

Sleeping too little certainly has a connection with issues with memory and cognition but could too much sleep also cause problems?

One observational study found that those who slept nine hours or more also had cognitive problems, such as decision making. However, Dr. Langbaum noted that whether too little or too much, in the end it’s about finding that sweet spot for you. “Each person’s sleep is unique,” Dr. Langbaum said. “If you’re sleeping well and waking up feeling rested, you shouldn’t be too concerned. But if you aren’t sleeping enough or find yourself sleeping too much, it’s a good idea to talk to your health care provider.”

If I improve my sleep, can I improve my cognition?

While more research is needed to determine the role that sleep has in preventing cognitive decline, taking steps to improve your sleep may reduce the long-term likelihood of developing mild cognitive impairment, Alzheimer’s disease and dementia.

“Sleep is essential to life,” Dr. Langbaum said. “Taken together, if you work on improving your sleep hygiene, address sleep issues like sleep apnea, focus on a healthy diet and exercise, you can help keep your mind sharp as you age.”

If you or someone you know is noticing problems with cognition and memory or excessive daytime sleepiness that is affecting thinking, schedule an appointment with your health care provider or a specialist as soon as possible. Early intervention is important.


Lack of sleep can have an impact on your memory and cognition in the short- and long-term. Getting enough quality sleep can help improve memory.

If you’re not sleeping well or have concerns about your memory, talk to your health care provider. There are options for getting better sleep and improving cognition so good sleep isn’t a distant memory.

To find a Banner Health specialist near you, visit bannerhealth.com.

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