Lack of sleep – effects on the brain

Lack of sleep, insomnia, or other sleep disturbances can lead to sleep deprivation. According to a 2015 study in Sweden, a third of the population says they don’t get enough sleep. Young people and the elderly are most susceptible to lack of sleep. In the case of young people, sleep deprivation can occur as a result of lifestyle. In older people, sleep deprivation occurs as a result of aging, as the duration of sleep decreases.

Other studies on this topic have shown that sleep deprivation leads to an increased risk of certain diseases, increased mortality, impaired memory and learning, etc. From a biological point of view, sleep deprivation leads to an increased level of activity of alpha and theta waves (demonstrated by EEG-electroencephalogram) …

Other symptoms include the appearance of moments when the subject loses concentration and attention to the environment, drowsiness and fatigue. Lack of concentration or attention can be caused by a decrease in glucose levels in certain areas of the brain (prefrontal lobe, parietal lobe). Other studies conducted in 2014 by the Institute for Basic Medical Sciences in Beijing showed that sleep deprivation (36 hours) affects the activity of the thalamus, amygdala, and cortical regions. Thus, synapses at these levels will no longer work properly.
The effects of sleep loss have also been studied by a group of Swedish researchers ( Nilsonne G. et al ., 2017). The study, as well as the results obtained are presented below.

Materials and methods

In a study conducted in 2017 in Sweden ( Nilsonne G. et al ., 2017), two groups of subjects were analyzed. The first group slept for several hours, depending on age. The second group slept for three hours. The study lasted one month. The age of the study participants ranged from 20-30 to 65-75 years. Were excluded people with neurological or mental illness, blind or those who wore glasses with lenses of more than 5 diopters, pregnant women, hypertensive patients, diabetics, smokers, addicts, including those who regularly drank coffee. To exclude people suffering from insomnia, a number of tests were applied: Depression and Anxiety Scale (HADS), Karolinka Questionnaire (KSQ).

During it, the participants slept at home. Thus, some errors were eliminated that could occur when changing the environment in which the subjects slept. Sleep was monitored with a polysomnograph . The polysomnograph was equipped with equipment for the following research methods: electroencephalograph (EEG), electromyograph (EMG), electrooculograph (EOG). Subsequently, the participants underwent an MRI (nuclear magnetic resonance) scan. During the experiments, the subjects’ eye movements were monitored on MRI. They were required to notify if subjects fall asleep. The movement of the eyeballs for more than 5 seconds was a signal to the researchers that the subjects were asleep.


Analysis of the results showed that lack of sleep leads to some changes in the brain. Some are age dependent, others not.

Sleep deprivation brain activity

The older ones showed a decrease in the functionality of the synapses compared to the younger ones.

Sleep deprivation showed no change in ReHo . ReHo (Regional Homogeneity) is a way to measure brain activity. Young people have increased activity at the level of the cerebral cortex (medial prefrontal cortex , superior temporal cortex ) and basal ganglia. Brain activity is more intense in the elderly in the orbitofrontal cortex .

Sleep deprivation oxygen levels

Oxygen levels in the brain declined in sleep-deprived elderly people . The decrease in oxygen levels in young people was less pronounced. Therefore, it is possible to establish a correlation between age and sleep duration in terms of the level of oxygen in the brain. This parameter returns to normal if the proper sleep duration is observed.

The results obtained showed little variability. This can be explained by changes in the respiratory flow.


The researchers concluded that partial sleep deprivation (a condition reported by Nilsonne G. et al ., 2017) does not cause major changes in the brain. Significant changes can occur if sleep deprivation is prolonged / moderate. According to other studies, they cause brain damage. The main changes occur at the level of the temporal lobe, at the level of areas involved in working memory or in the decision-making process. The most obvious sign of sleep deprivation is cognitive decline. This can happen in the event of complete or partial sleep deprivation, but is achieved over a longer period of time.

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