It is known that it is recommended to sleep 7 to 8 hours a day and that the lack of sleep affects our body, which suffers from tiredness . However, the effects of lack of sleep seem to go far beyond physical symptoms, and can also alter our emotional responses, learning ability and ability to make good decisions.
Check out how lack of sleep can affect our brain and even our personality:
Negative emotions and stress
Perhaps this is the second most recognized symptom of lack of sleep: stress . Aside from tiredness, stress also seems to be increased when we are not sleeping well.
Studies indicate that people who sleep less end up having more pronounced negative emotions than those who sleep the recommended number of hours per day.
The cerebellar tonsils, neurons responsible for feelings and emotions, respond significantly more than when the person is well rested. When there is a lack of sleep, there is a disconnection between the cerebellar amygdala and the prefrontal cortex, which, among other functions, is responsible for “curbing” emotional reactions. This ends up causing negative emotions more often.
Other studies show that people with sleep deprivation experience stress during simple cognitive tests, while rested people do not feel as much. In more complex cognitive tests, the stress level of people with sleep deprivation and rested people is the same, showing that the person who does not sleep well does not feel more intensely, but more often.
This is because, as described above, the connections between the cerebellar tonsils and the prefrontal cortex are broken, causing negative feelings to take over. In the long run, the person may end up developing depression and, consequently, have insomnia, turning into a vicious circle.
Ability to make decisions
Lack of sleep can affect our ability to consider possibilities, make decisions and reach plausible and even realistic conclusions.
An example of this is the people in casinos. Tired bettors have a tendency to choose bets with a higher monetary gain than bets that reduce losses.
Researchers at Duke University have studied the effects of sleep deprivation on the economic preferences of young adults. Participants performed tasks that involved bets and the researchers found that lack of sleep made people more optimistic, believing that the positive consequences (gains) were more likely than the negative ones (losses).
While the research only talks about the financial, it is possible that sleep deprivation affects our judgment in other aspects as well.
Memory and learning
Another capacity impaired by sleep deprivation is memory and, consequently, learning. That’s because lack of sleep directly affects the hippocampus, part of the brain responsible for storing new memories – in addition to being strongly associated with emotions.
A sleepless night significantly reduces the activity of the hippocampus when coding episodic memories, that is, when it comes to storing what happened. Therefore, this decrease in activity also ends up affecting the quantity and quality of information that is retained in memory.
Another theory is that some of the events in the brain that are responsible for memory consolidation occur during the deepest levels of sleep. These events transfer new information from the hippocampus to the neocortex, where long-term memories are stored.
Symptoms of psychosis and schizophrenia
The ability to filter information is reduced and there are those who report greater sensitivity to colors, lights and brightness.
The standard test for measuring the brain’s ability to filter information is what is called Pre-Pulse Inhibition. In the test, the individual hears a loud noise through headphones. The rapid and intense response – probably a scare – is captured by electrodes that measure the contraction of facial muscles. When a lower noise (pre-pulse) is heard before the loud noise, the fright is not so great. Thus, the pre-pulse inhibits the individual’s response (fright).
In schizophrenic patients and in people with sleep deprivation, the pre-pulse does not inhibit the reaction, causing the person to end up getting the scare anyway, even if there is a lower noise before. The researchers concluded that, after 24 hours without sleep, the brain lacks the ability to filter information.
Drowsiness causes accidents
On the roads, sleep deprivation is one of the main factors that lead to car accidents. That’s because drowsiness slows reflexes as much as alcohol, causing slow reactions.
In repetitive work, the incidence of accidents is higher for people who suffer from sleep during the day.
Risks of chronic diseases
In the long run, sleeping less than enough can increase the risk of developing chronic illnesses like diabetes , hypertension, stroke and cardiovascular disease.
That’s because sleep deprivation significantly affects how metabolism works. Studies show that people who sleep little suffer more from stress, high blood pressure , difficulties in controlling glucose and a greater likelihood of inflammation, these being risk factors that can lead to the aforementioned diseases.
Increased appetite and obesity
Sleep reduction is associated with changes in hormones that control hunger. There are studies that show that sleep deprivation is related to an increase in the desire to eat sweets and other foods rich in carbohydrates .
The energy expenditure of people who sleep less is also less, as they do not tend to be physically active.
One should also take into account the fact that the longer you stay awake, the more time you can spend eating food and drinks.
Men and women report reduced libido when they sleep less. Some of the causes for this may be the lack of energy, drowsiness, tension and stress that are more prominent.
For men, it gets even more complicated if they suffer from apnea. A 2002 study by the Journal of Clinical Endocrinology & Metabolism shows that men who suffer from this disease, characterized by breathing stops during sleep, have reduced testosterone levels.
Worsens skin health
Dark circles are not the worst thing that a lack of sleep can cause on the skin. Although they are very common and make it clear that the person is not sleeping properly, sleep deprivation also causes the appearance of fine lines and dull skin under the eyes.
Due to lack of sleep, the body releases more cortisol which, in excessive amounts, can break down collagen in the skin.
Increased risk of death
The Whitehall II Study, a vast study of cardiovascular disease and death rates, examined how sleep patterns affected the mortality of more than 10,000 British civil servants over two decades. The results show that those who slept less doubled the chances of dying from any cause.
The effects of sleep deprivation end up being more damaging than you think, and it is extremely important to pay attention to your routine. There are several diseases and conditions that can cause lack of sleep or poor quality sleep, such as insomnia, depression and night apnea.
If you have trouble sleeping at night or feel like you don’t get enough sleep, see a doctor.