Deep sleep may reduce memory loss caused by Alzheimer’s disease

Credit: David Mao / Unsplash

A recent study by researchers at the University of California, Berkeley, suggests that deep sleep might offer protection against memory loss in older adults at risk for Alzheimer’s disease.

This type of sleep, also known as non-REM slow-wave sleep, seems to act as a “cognitive reserve factor,” creating a buffer against the harmful effects of beta-amyloid—a protein linked to dementia-related memory loss.

The Science Behind Sleep and Dementia

Disrupted sleep has previously been connected to faster accumulation of beta-amyloid protein in the brain.

However, the UC Berkeley team’s new research implies that ample deep, slow-wave sleep might protect against memory decline in those with high amounts of Alzheimer’s disease pathology.

This is a potentially significant advance that could help mitigate some of dementia’s most severe consequences.

The Power of Lifestyle Factors

Zsófia Zavecz, a postdoctoral researcher at UC Berkeley’s Center for Human Sleep Science, explained, “People should be aware that, despite having a certain level of pathology, there are certain lifestyle factors that will help moderate and decrease the effects.

One of those factors is sleep and, specifically, deep sleep.”

Unveiling the Role of Beta-Amyloid

Alzheimer’s disease, the most common form of dementia, destroys memory pathways and, in advanced forms, interferes with a person’s ability to perform basic daily tasks.

In recent years, scientists have investigated the association between deposits of beta-amyloid and Alzheimer’s disease and how these deposits affect memory more generally.

Sleep as a Cognitive Reserve Factor

Elements like years of education, physical activity, and social engagement are believed to improve a person’s resilience to severe brain pathology, functioning as cognitive reserve factors.

Yet, most of these factors, such as past years of education or the size of one’s social network, cannot be easily changed retroactively.

Matthew Walker, a UC Berkeley professor of neuroscience and psychology, highlighted the importance of sleep in this context, stating, “If we believe that sleep is so critical for memory, could sleep be one of those missing pieces in the explanatory puzzle that would tell us exactly why two people with the same amounts of vicious, severe amyloid pathology have very different memory?”

The Study and its Findings

The researchers recruited 62 older adults from the Berkeley Aging Cohort Study.

Participants, who were healthy adults and not diagnosed with dementia, slept in a lab while researchers monitored their sleep waves with an electroencephalography (EEG) machine.

A positron emission tomography (PET) scan measured the amount of beta-amyloid deposits in the participants’ brains.

The results showed that those with high amounts of beta-amyloid deposits who also had higher levels of deep sleep performed better on a memory test than those with the same amount of deposits but who slept worse.

Essentially, deep sleep seemed to mitigate the detrimental effects of beta-amyloid pathology on memory.

The Importance of Sleep Hygiene

Walker likened deep sleep to a life raft that keeps memory afloat, rather than letting it be dragged down by Alzheimer’s disease pathology.

He emphasized that there are ways to improve sleep, even in older adults.

These include sticking to a regular sleep schedule, staying mentally and physically active during the day, creating a cool and dark sleep environment, and minimizing things like late-day coffee and screen time before bed.

Taking a warm shower before bedtime can also enhance the quality of deep, slow-wave sleep.

The Road Ahead

While the study involved a small sample size of healthy participants, it’s an early step in comprehending how sleep might ward off memory loss and the progression of Alzheimer’s.

The researchers hope that the findings will pave the way for more extensive studies exploring sleep-enhancement treatments.

If you care about sleep, please read studies about high blood pressure drugs that may increase sleep loss, and heavy blankets could increase melatonin and improve sleep.

For more information about sleep, please see recent studies about sleep apnea linked to Alzheimer’s disease, and results showing this exercise can help you sleep better.

The study was published in BMC Medicine.

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