Slow Wave Sleep Critical For Reducing Dementia Risk

Reducing Dementia Risk: Slow Wave Sleep

The risk of getting dementia goes up as you get older, and the risk is greater if you don’t get enough deep sleep. A new  scientific study published in  JAMA Neurology shows that even a small difference  in the amount of deep sleep a person has will impact their risk of dementia. The technical term for this stage of sleep is Slow-wave sleep . It is the third stage of the natural 90-minute sleep cycle, which lasts approximately 20–40 minutes.  Slow-wave sleep appears to play a key role in making sleep refreshing and reducing the pressure to sleep during the day. Other functions of slow-wave sleep include supporting memory, boosting immune function, facilitating the growth and repair of tissues, and enabling the elimination of waste products from the body.

Learning and memory: Research shows us that the brain activates newly acquired memories during slow-wave sleep helping them to become part of a person’s long-term memory. Also, slow-wave sleep may facilitate learning by helping to restore connections between brain cells that can become overwhelmed during waking hours. This stage of sleep is the most restful stage, where brain waves and the heart rate slows, and blood pressure drops. The results of the study showed that people are more likely to get dementia if they lack getting enough of this slow wave sleep.

Deep sleep prepares the brain to absorb more information.  Recent research from U.Berkely-Stanford earlier this year, research discovered that individuals with Alzheimer’s-related changes in their brain did better on memory tests when they got more slow-wave sleep.tps://

Neuroscience researcher Dr Matthew Pase of the Monash U. in Australia says,  “Slow-wave sleep, or deep sleep, supports the aging brain in many ways, and we know that sleep augments the clearance of metabolic waste from the brain, including facilitating the clearance of proteins that aggregate in Alzheimer’s disease. However, to date we have been unsure of the role of slow-wave sleep in the development of dementia. Our findings suggest that slow-wave sleep loss may be a modifiable dementia risk factor.”

Their study included 346 people enrolled in the Framington Heart Study who were monitored during two overnight sleep studies between 1995 and 1998 and again between 2001 and 2003, with an average of five years between testing periods. None of the participants had dementia when they were monitored during the 2001-2003 period. These people were then assessed for potential  development of dementia when they were over sixty years old starting in 2018. Lead researcher Dr. Pace explains, “We used these (studies) to examine how slow-wave sleep changed with aging and whether changes in slow-wave sleep percentage were associated with the risk of later-life dementia 17 years later.

In the 17 years of follow up, 52 dementia cases were recorded among the participants. Participants’ slow-wave sleep levels recorded in the sleep studies were examined to evaluate the effect of slow wave sleep deprivation and development of dementia.

By comparing participants’ first and second sleep studies, researchers discovered a link between each percentage point decrease in slow-wave sleep per year and an increased risk of developing dementia.

How Can We Get More Slow Wave Sleep?

There are things that you can to get more of this crucial slow-wave sleep.

Wearing on Eye Mask While Sleeping

Blocking out low level light that is still present in yoru room when you sleep improves alertness and memory the following day, as per research conducted in two experiments with a total of 122 participants. This was done via collaboration of researchers from the UK, Italy, and the US. They provided evidence of the link between light and sleep – and that by blocking out ambient light helps to enhance deep sleep. Their study write concluded that “Ambient light can influence sleep structure and timing. We explored how wearing an eye mask to block light during overnight sleep impacts memory and alertness, changes that could benefit everyday tasks like studying or driving.”

In the first experiment, 89 adults aged 18 to 35 were asked to wear an eye mask while sleeping for a week.Testing done over the two days of each week showed that the study subjects were more able to recall events and experiences, after having their eyes covered while sleeping. They also performed better on a test that measures reaction times.

In the second experiment, 33 subjects  aged 18 to 35 were given eye masks, and a headband which measured brain activity while they slept. Their data showed that wearing an eye mask helps with learning new information and forming fresh memories. In addition, data provided by the headband suggests there is an association between mask wearing and more slow-wave sleep time, known to be important when it comes to memory boosts. The study states, “The benefit to memory was predicted by time spent in slow-wave sleep while wearing the mask. This suggests wearing an eye mask during sleep is an effective, economical, and non-invasive behavior that could benefit cognitive function and lead to measurable impacts on everyday life.”

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