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Sleeping badly causes early cognitive impairment

Sleeping badly causes early cognitive impairment

When we sleep, our body continues to work to maintain overall health. Sleep protects our heart and our brain and improves cognitive abilities such as attention or memory, as well as emotional and psychological stability. That is why a good quality of sleep can be key to the correct cognitive functioning. In addition, the consequences of sleeping poorly are not only limited to cognitive impairment, but also to poor cardiovascular health, psychological problems and metabolic disorders, among others.


  • 1 Sleep quality and cognitive functioning
  • 2 What happens in our brain while we sleep?
  • 3 Sleep and disease risk
  • 4 The importance of sleeping well

Sleep quality and cognitive functioning

A recent study carried out by the Karolinska Institute in Stockholm has shown the connection between a poor sleep quality and future cognitive deterioration in old age. In this investigation, sleep patterns and cognitive abilities of 3400 people were studied for more than two decades.

In the results of the study it was found that those people who suffered insomnia or nightmares between 40 and 60 years, obtained a higher probability of presenting cognitive impairment in old age, especially when these problems occur for more than three years. These results were also obtained in two other investigations with people between 70 and 80 years old.

According to the principal investigator of this study Sireen Sindi: “We can all have specific difficulties in sleeping, whether due to a high level of stress, the consumption of caffeine or alcohol or due to a time lag. However, if a person has chronic problems, both when falling asleep and waking up in the middle of the night or too early, it is important to seek help from a healthcare professional. ”

In another research led by Katja Linda Waller at the University of Copenhagen, 189 healthy men were studied to see if there was any connection between their sleep quality and cognitive impairment. The participants, all born in 1953, were divided into two groups depending on whether they had cognitive impairment or not. Subsequently, characteristics such as sleep quality or depressive symptoms were studied, among others. The results showed again how people who showed lower cognitive performance also had a worse quality of sleep.

What happens in our brain while we sleep?

The importance of sleeping well is key to preserving cognitive functions such as learning and memory: During deep sleep, NREM, explicit memory is strengthened, which is associated with declarative knowledge, while during REM phase memory is strengthened implicit with which we are able to remember skills.

When we sleep, the brain reinforces the most important synapses we have created during the day, that is to say, those new neuronal connections fruit of experiences that have made us learn. In addition, less important synapses are eliminated in order to end an excess of neuronal connectivity that prevents the proper functioning of the brain. That is, while we sleep our brain selects the most important lessons of the day to be conserved and eliminates excess connections to continue learning correctly. When we do not sleep well, the ability to learn and remember what is learned is limited. Therefore, work performance, academic or simply, daily, can decrease when people do not sleep enough hours.

In addition, a poor quality of sleep is associated with the feeling of daily sleepiness, which prevents a good concentration in tasks and triggers a low attention span.

Sleep and disease risk

We recently published a study that showed how the act of sleeping gets the brain cleaned of toxins. When people sleep, the glial cells that maintain brain function shrink, giving way to a greater amount of cerebrospinal fluid, a substance that cleanses the brain of toxins and maintains brain health. Brain "cleansing" that occurs during sleep also removes a peptide called beta amyloid, which causes senile plaques that characterize Alzheimer's disease. Poor elimination of this peptide due to poor sleep quality is also associated with the development of this disease.

The importance of sleeping well

In addition to the cognitive problems that may occur due to poor sleep quality, psychological health is also compromised for this reason; According to a study carried out in 2016, insomnia is associated with a high risk of depression, something that happens in a circular way: people who suffer from depression tend to have more sleep problems, as well as people with sleep quality problems, usually have a higher risk of depression. Luckily, the quality of sleep is something that can be discussed and about which there is increasing awareness, both academically and socially. It is necessary to look for a sleep professional if we believe that we are not sleeping properly, since the importance of sleeping well is key to leading a healthy life both physically and psychologically.

Links of interest

Sleep deprived? What missing too much sleep might be doing to your body. Leslie Young //

Decreased deep sleep linked to early signs of Alzheimer's disease. (2019). //