Contrary to popular belief, mental stress does not require a large number energy. So physical fatigue after intellectual work is self-hypnosis, according to recent studies.

Every day, from September to June, they fall out of classrooms and classrooms, their eyes adjusting to sunshine, and fingers fumble in search of smartphones. Some raise their hand to their foreheads, as if trying to brush off a headache, others with glassy eyes loom in the yard, not understanding what to do, still others crowd in the dining room. They're exhausted, but not from kicking balls or lifting weights all day. Most likely, these guys are the victims of intensive preparation for exams.

Temporary mental exhaustion - absolutely real story. It is important to note that this is not the same as chronic fatigue, usually associated with lack of sleep and some physical ailments. Thinking and increased concentration of attention require more energy than ordinary mental processes. Just as intense sports are physically exhausting, intellectual work exhausts the brain - what could be easier? However, recent studies have shown that this is not entirely true.

The fact is that our voracious brain constantly consumes a huge amount of energy, regardless of whether we are solving integrals or watching the top coolest cats on the Web. Although a heavy mental load requires additional blood flow, glucose and oxygen, the increase in energy consumption compared to the hourly needs of the brain is minimal. In most cases, short periods of mental stress require a small amount of energy - nothing more. But somehow we get exhausted when we think hard. Maybe it's just self-indulgence?

Although the adult brain weighs on average about one and a half kilograms, which is 2% of body weight, it is necessary to maintain the vital functions of the body. Even when we do nothing, our body is in full swing: the heart pumps blood, the lungs breathe, the stomach digests food, and the brain controls these processes - and we burn calories. The level of metabolism, or metabolism (RMR), depends on the age, sex, weight and health of the person.

brain power

Let's do some math. If you take an average metabolic rate of 1300 kcal per day, the brain takes 260 kcal - just to control everything. This is 10.8 kcal per hour or 0.18 kcal per minute. If we translate all this into power, it turns out that the brain consumes a little more than 12 watts - one-fifth of an ordinary light bulb. Compared to other organs, the brain is insatiable; compared to electrical appliances - extremely unpretentious.

Energy enters the brain through blood vessels in the form of glucose, which is converted into ATP - the main source of energy within cells. Animal and human experiments have shown that when neurons in a particular area of ​​the brain fire, local capillaries dilate to deliver a little more blood with extra glucose and oxygen. Research has also confirmed that brain cells consume extra glucose.

Based on this, scientists have proposed the following: if increased activity neurons require additional glucose, then complex mental tasks should lower blood glucose levels. Accordingly, eating foods rich in sugar improves brain performance. While some research has supported this view, the evidence is mixed. Any changes in blood glucose levels were taken into account - from enormous to insignificant.

Robert Kurtzban from the University of Pennsylvania cites work that shows that small physical activity improves concentration. One study found that children who walked 20 minutes on a treadmill did better on tests than those who read quietly in a corner. If mental effort were linked to glucose intake, then the "runners" would fail the test, as they expended more energy than their calmer peers.

Lee Gibson of Roehampton University believes that the effect of task difficulty on energy costs is a myth. It all depends on individual features of a person: degree of participation, effort, age, and even blood sugar regulation. Cola and chocolate will help solve a difficult problem only for those who have not eaten for three days. In most people, the body itself copes with the supply of energy.

Mind and body

If the thought process consumes little energy, then why do we get so tired when preparing for exams and other intellectual marathons? There is an opinion that long-term continuous concentration on a task really burns energy, but previous researchers were too soft on their charges - so the experiments did not prove anything. Typically, participants in the experiment perform one task of moderate difficulty - an hour or two, no more. “Maybe if we get people to do longer, harder tasks — especially ones that they're not good at — we'll see clearer results,” Messier suggests.

The feeling of fatigue in us is caused by the mental load that was imposed on us - hardly anyone prepared for exams in boring subjects with pleasure. We are especially exhausted by the thought that the test will be difficult - and the more we think about it, the harder it seems to us. A lot of physical fatigue is actually in our heads. In a small experiment, people who exercised on a stationary bike after an hour and a half test of attention span stopped pedaling earlier than those who relaxed watching a movie before the test. The attention test does not require more energy than a movie, but test participants complained that the test took all of their energy. And the thought of it was enough to reduce performance.

In the case of exams, the stress that the body experiences plays a big role. After all, the brain does not work in a vacuum. Other organs also burn energy. Schoolchildren realize that this exam determines where they will spend the next four years of their lives. Therefore, they are worried, and their body is worried along with them. Stress hormones are injected into the bloodstream, the heart rate accelerates, sweating increases, behavior becomes fussy, movements become abrupt. As a result, exams exhaust not only mentally, but also physically.

A small but interesting study shows that even mild challenges to the intellect change our emotional state. Fourteen Canadian female students either retold small text, or solved the 45-minute test. Then everyone went to the dining room. As a result, the girls who solved the test ate 200 more calories than those who did the retelling. Blood glucose levels fluctuated, but irregularly. But the level of cortisol, the stress hormone, in the mentally overloaded went through the roof - as well as heart rate, blood pressure and anxiety. It turns out that the students ate more not because the brain sucked out all their energy - they seized stress.

Equally important is attitude. After an interesting two-hour film with a complex narrative, we do not fall out of the cinema, complaining of fatigue. Some of us eagerly read thick novels, someone solves complex crossword puzzles - and this does not prevent us from focusing on other tasks during the day, but, on the contrary, gives us strength. Sometimes we consciously use intellectual activity to cheer ourselves up.

Messier has his own explanation for fatigue. “My hypothesis: the brain is a lazy fool who does not want to work long and hard. It is difficult for him to focus on one thing. It is possible that maintaining concentration changes something in the brain, and it begins to take off. Maybe we have a timer in our head that reminds us that we have had enough,” said Messier.

Faktrum offers a collection of facts about how our brains and consciousness work.

1. You suffer from "inattentional blindness"

Watch the next video. You need to count the number of passes made by people in white shirts. Watch the video BEFORE you continue reading.

This is an example of what is called "inattentional blindness." The idea is that we are often blind to what is literally “under our noses” if we are focused on some other task.

AT this case, a man in a gorilla suit walks through a group of players, stops and walks away. Participants who are busy counting passes often simply do not notice the gorilla. What's more, those who are aware of the gorilla's appearance become even more inattentive and miss other changes, such as the change in color of the curtains and the departure of one of the girls.

2. You can only memorize 3-4 items at a time

There is a rule of "magic number 7 plus minus 2", according to which a person cannot store more than 5-9 blocks of information at the same time. Most of the information in short-term memory is stored for 20-30 seconds, after which we quickly forget it, if we do not repeat it again and again.

Although most people can hold about 7 digits in memory for a short period, almost all of us find it difficult to keep 10 digits.

Recent studies show that we are able to store even less: about 3-4 blocks of information at a time. An example is a telephone number: it is divided into several numerical blocks to make it easier to remember.

3. We do not perceive the combination of red and blue color well.

Although these colors are used in many national flags, red and blue are hard to perceive by our eyes when they are next to each other.

This is due to an effect called "chromo stereoopsis" which causes some colors to "pop out" while others are removed. This causes irritation and eye fatigue.

This effect is most pronounced when combining red and blue, as well as red and green colors.

4. You see things differently than you perceive them.

According to a study by the University of Cambridge, “there are no gaps in any subdiacra in the left. Smaoe vaonzhe - these are the ways of the first and the bottom of the bkuva of the blyi on their own metsah.

Even if the rest of the letters are mixed up, you can still read the sentence. This is because the human brain does not read each letter, but the word as a whole. It is constantly processing information from the senses and how you perceive information (words) tends to be different from what you see (messy letters).

5. You are able to maintain close attention for about 10 minutes.

Even if you are in a meeting, you are interested in the topic, and the person presents the subject in an interesting way, then maximum time of your undivided attention - 7–10 minutes. After that, attention will begin to weaken and you will need to take a break in order to continue to maintain interest in the topic.

6. The ability to delay gratification begins in childhood.

Your ability to delay the immediate gratification of your desires arises even in early childhood. People who can delay gratification from an early age do better in school and cope better with stress and frustration.

7. We dream 30% of the time

Do you like to be in the clouds? According to psychologists, we all love to dream at least 30% of the time. Some of us are even bigger, but that's not always a bad thing. Researchers say that people who like to daydream tend to be more resourceful and better problem solvers.

8. It takes an average of 66 days to form a habit.

The more complex the behavior we want to reinforce, the longer it will take. For example, those who wanted to develop the habit of exercising regularly were more likely to take 1.5 times more time than those who developed the habit of eating fruit for lunch. Even if you skip a day or two, it won't affect the timing of the habit, but skipping too many days in a row can slow down the process.

9. You overestimate your reaction to future events.

We are not very good at predicting the future. To be more precise, we overestimate our reaction to future events, whether pleasant or negative.

Studies have shown that people believe that positive events, such as marriage or a big win, will make them much happier than they actually are. Likewise, we believe that negative events, such as losing a job or an accident, will cause us to feel much more depressed than we actually do.

10. You blame the other person, not the situation (and the situation, not yourself)

Recall a time when you were waiting for another person who was late for a meeting. Most likely, you attributed his delay to irresponsibility and lack of concentration. In a similar situation, you would attribute your own lateness to external circumstances (traffic jams).

In psychology, this is called the "fundamental attribution error" - the tendency to explain the behavior of others by the internal characteristics of the personality, and one's own - external factors(“I had no choice”, “I was not lucky”).

Unfortunately, even though we are aware of our tendency to make unfair judgments, we still continue to make this mistake - the propensity for it is inherent in all people from birth.

11. The number of friends you can have is limited.

Even though you may boast of having a few thousand social media friends, you actually have far fewer of them. Psychologists and anthropologists have identified the "Dunbar number" - that is, the maximum number of close relationships that a person can have, and it ranges from 50 to 150.

12. You can't ignore food, sex, and danger.

Have you noticed that people always stop to look at accident scenes. But we cannot ignore the situation of danger. Every human has an ancient survival area of ​​the brain that asks, “Can I eat this? Is it possible to have sex with this? Can it kill me?"

Food, sex and danger are the most important things. After all, without food, a person will die, without sex, the race will not continue, and if a person dies, the first two points will not make sense.

13. You know how to do things you've never done before.

Imagine that you have never seen an iPad, but they gave you one and offered to read books on it. Even before you turn on the iPad and start using it, you will already have assumptions in your head about how the book will look on the screen, what features you will be able to use, and how you will do it.

In other words, you have a "mental model" of reading a book on a tablet, even if you've never done so. It will be different from the model that a person who has read e-books before and who does not know what an iPad is has.

These models are based on incomplete facts, past experience and intuition.

14. You want more choices than you can handle.

If you go to any supermarket, you will see a huge range of products, because people "need a lot of choice."

In one supermarket study, researchers presented participants with 6 types of jam and then 24 types of jam. And while people were more likely to stop at a 24-jam stand, they were 6 times more likely to buy jam at a 6-jam stand.

The reason for this is simple: despite the fact that we feel like we want more, our brains can only handle a limited number of items at once.

15. You are happier when you are doing something.

Imagine that you are at the airport and you need to pick up your luggage. However, it will take you about 12 minutes to reach the baggage claim area. When you approach the baggage claim, you immediately pick up your suitcase.

Now try to imagine a similar situation, but only you get to the pick-up line in 2 minutes and wait for the suitcase for 10 minutes. Although in both situations it took you 12 minutes to get your luggage, in the second case you were probably more impatient and unhappy.

If a person has no reason to be active, he decides not to do anything. While it helps us conserve energy, idleness makes us feel impatient and unhappy.

16. You make most decisions subconsciously.

While we like to think that our decisions are carefully controlled and thought out, research suggests that everyday decisions are actually subconscious, and for a reason.

Every second, our brains are attacked by more than 11 million individual pieces of data, and since we cannot carefully check all this, the subconscious mind helps us make a decision.

17. You change your memories

We think of our memories as little "movies" that we play in our head and think they are stored just like a video in a computer. However, it is not.

Every time you mentally return to an event, you change it, because the neural pathways are activated differently each time. Later events may also influence this. and the desire to fill in the gaps in memory.

So, for example, you don't remember who else was at the family reunion, but since your aunt was usually present, you can eventually include her in your memory.

18. You can't multitask at the same time.

If you think you're great at multiple things at once, you're wrong. Scientists have proven that we cannot do 2-3 things at once. Of course, we can walk and talk to our friend at the same time, but our brain only focuses on one priority function at any given time.

The thing is, we can't think about two different things at the same time.

19. Your most vivid memories are wrong.

Memories of exciting and dramatic events are called "flash memories" in psychology, and they, as it turned out, are full of errors.

Well-known examples of this phenomenon are the events associated with 9/11. Psychologists asked the participants to describe in detail what they did, where there were other details immediately after the attack and 3 years later.

It turned out that 90% of later descriptions differed from the original ones. Many people can describe in detail where and what they were doing at the moment they heard the news. The only problem is that these details are incorrect, as the strong emotions associated with memory distort memories.

20. Your brain is just as active in sleep as it is when you are awake.

When you sleep and dream, your brain processes and accumulates the experience of the whole day, creates associations from the information received, decides what to remember and what to forget.

Surely you have often heard the advice to "get a good night's sleep" before an exam or an important event. If you want to remember what you have learned, it is best to go to bed immediately after you have learned the material and give your brain time to sort out the information.

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compared to Europe, women are significantly underrepresented in research and development.

recent studies show that women are markedly under-represented in scientific research and development by European standards.

Recent studies show that women are markedly under-represented in scientific research and development by European standards.">

due to women's traditional role in society, they bear the brunt of the cost of structural adjustment.

Recent studies demonstrate that because of the traditional role of women in society, the major burden of structural adjustment costs is being shifted to them.

Recent studies demonstrate that because of the traditional role of women in society, the major burden of structural adjustment costs is being shifted to them.">

Recent studies show that when unpaid and seasonal work is taken into account, women's contribution to agricultural production becomes very significant.

Recent studies have shown that women's contributions to agriculture are significant when unpaid and seasonal labor is taken into account.

Recent studies have shown that women "s contributions to agriculture are significant when unpaid and seasonal labor is taken into account.">

Recent studies show that If atmospheric CO2 increases, the ability of the oceans to absorb CO2 may decrease.

Recent studies indicate that, while atmospheric CO2 is increasing, the ability of the oceans to absorb CO2 may be decreasing.

Recent studies indicate that, while atmospheric CO2 is increasing, the ability of the oceans to absorb CO2 may be decreasing.">

Recent studies show that To improve our understanding of the global structure of atmospheric dynamics, additional information is required on issues such as momentum and motion in the horizontal plane in the middle thermosphere.

Recent studies show that Sources are just as important as content, as they are closely related to accountability (see paragraph 22).

Recent research shows that sources are just as important as content, since they are closely linked to lines of accountability (see paragraph 22).

Recent research shows that sources are just as important as content, since they are closely linked to lines of accountability (see paragraph 22).">

Recent studies show that health sector workers may be at greater risk of exposure to chemicals in their own workplaces than the general population.

Recent research has shown that health-sector employees may be more at risk than the general public from chemicals used in their own workplaces.

Recent research has shown that health-sector employees may be more at risk than the general public from chemicals used in their own workplaces.">

Recent studies show that the elimination of subsidies, mainly to households in eight developing countries and countries with economies in transition, has resulted in significant environmental benefits.

Recent investigations show that elimination of subsidies aimed largely at households in eight developing countries and economies in transition resulted in significant benefits to the environment.

Recent investigations show that the elimination of subsidies largely at households in eight developing countries and economies in transition resulted in significant benefits to the environment.">

Recent studies show that Gypsy and Traveler life expectancy is 10 years less than the national average and that they have the highest infant mortality rates of any ethnic minority, two common measures of community poverty.

Recent studies indicate that the life expectancy of gypsies and travelers is 10 years lower than the national average and that they experience the highest rates of child mortality of any ethnic minority - both common poverty indicators.

Recent studies indicate that the life expectancy of gypsies and travelers is 10 years lower than the national average and that they experience the highest rates of child mortality of any ethnic minority - both common poverty indicators.">

Recent studies show that it will evaporate or break up into two in a few tens of millennia, or be ejected from the solar system in a few hundred thousand years.

More recent work suggests that Halley will evaporate, or split in two, within the next few tens of thousands of years, or will be ejected from the Solar System within a few hundred thousand years.

More recent work suggests that Halley will drain, or split in two, within the next few tens of thousands of years, or will be ejected from the Solar System within a few hundred thousand years.">

Recent studies show that in Latin America and the Caribbean over the past 10 years, more than 1 million people have died in road traffic crashes and about 10 million people have been injured or disabled.

In the Latin America and the Caribbean (LAC) region recent studies estimate that around 1 million people have died and around 10 million have been injured or disabled in road accidents during the last 10 years old

Recent studies estimate that around 1 million people have died and around 10 million have been injured or disabled in road accidents during the last 10 years.">

However recent research shows that a set of financial and non-financial elements is needed to attract, retain and engage staff.

However, recent research revealed that individuals were attracted, retained and engaged by a range of both financial and non-financial elements.

Recent research revealed that individuals were attracted, retained and engaged by a range of both financial and non-financial elements.">

But recent research shows that it prevents syphilis, which is why we do it.

Marijuana for Alzheimer's. Scientists at the Salk Institute for Biological Research (USA) found that the main psychoactive substance in marijuana, tetrahydrocannabinol (THC), and several other active compounds destroy beta-amyloid plaques on laboratory-grown neurons. Beta-amyloid is a toxic protein that accumulates in the brains of people with Alzheimer's disease. The disease progresses due to cellular inflammation in the brain, which is also weakened by the psychoactive substances of marijuana. The main merit of the study is that it opens up new horizons in the study possible effects marijuana.

Our brain memory is 10 times larger than we thought. We value our brains for their ability to store and process large amounts of information. But research by a group of American scientists from the University of California found that the real capabilities of the brain are ten times greater than previously believed. Scientists have proven that the human brain is capable of holding as much information as the world's Internet space can hold. To come to this conclusion, the scientists built a 3D model of the hippocampus of brain neurons (the hippocampus is a part of the limbic system of the brain involved in the consolidation of short-term memory into long-term memory), in which transitions and synapses are repeated twice in 10% of cases. Scientist Terry Sezhnowsky called it "a real bombshell" in the field of neuroscience.

Painkillers exacerbate chronic pain. Recent studies have shown that just 5 days of morphine treatment in rats resulted in chronic pain that lasted for months. The opioid drugs affected the behavior of glial cells in the experimental animals: these cells are supposed to protect the nerves of the spinal cord and brain from damage, but after repeated use of morphine this does not happen, and increased sensitivity to pain appears. If the results of the study are similar in the case of humans, this would explain the dependence on strong painkillers: by helping on a superficial level, drugs prolong and increase pain in the long term.

Sugar is like a drug. Our habits affect how our brains work in strange ways. For example, even such signals nervous system how "stop" and "go" change under the influence of sugar addiction. Like other drugs, sugar addiction affects how the brain controls electrical signals associated with either the pursuit of pleasure or the suppression of this desire. It turns out that sugar cravings are not just appetite and taste preferences, but the result of brain changes caused by powerful chemical effects. This is another study that proves that we underestimated the effect of sugar on our body. By the way, another scientific paper from last year looks at genetic memory damage caused by fructose. Most likely, the topic of our brain's dependence on sweets will become one of the most relevant in science in the near future.

Happiness is in the genes? In one of the largest studies to date, examining the relationship of mood and human condition with genetics, scientists came to the conclusion that the roots of our psychological worldview lie in the genome. More than 190 researchers from 17 countries have analyzed the genome data of almost 300,000 people. The results showed themselves in a set of genetic variations associated with subjective feelings of well-being — that is, the thoughts and feelings we have about the level and quality of our lives, which psychologists define as a central component of happiness. Similarly, genetic variations have been found associated with depression and neurosis. The next question is how these variations interact with our environment, and whether depression can be detected by genetic testing before its clinical manifestation.

Prevention of Alzheimer's disease: first steps. Last year's research has opened up new avenues for developing drugs to prevent Alzheimer's disease, and possibly other neurodegenerative diseases such as Parkinson's disease. Employees at Baylor College of Medicine, scientists at the Texas Children's Hospital and Johns Hopkins University School of Medicine are working together to find ways to prevent the accumulation of toxic proteins in the human brain - that is, to work ahead of time, and not destroy already formed tau proteins. This is a big breakthrough in the fight against Alzheimer's because the main research so far has been focused on treating the advanced stages of the disease.

How sleep apnea affects the brain. Sleep apnea is a sudden stoppage of breathing that can last 20-30 seconds, and sometimes longer. Sleep apnea is often associated with an increased risk of stroke, depression, and traffic accidents. Research has shown that restless nights with sleep apnea trigger a kind of chemical rollercoaster, throwing out the neurotransmitters GABA (gamma-aminobutyric acid) and glutamate. As a result, sleep apnea sufferers are more sensitive to stress, have trouble concentrating, and are prone to frequent emotional swings.

Walk for happiness. Among the many studies studying the beneficial effects of walking on the emotional state of a person, one of the recent works can be distinguished. So, scientists say that walking improves mood, even when we do not expect and do not plan for such an effect. In the course of three experiments, in which more than a hundred people took part (who did not suspect that the process of walking was one of the objects of study), it was found that in just 12 minutes of walking, the cheerfulness, energy, attentiveness and self-confidence of the subjects increased, compared with the same time spent sitting. An important and pleasant conclusion: the fight against depression and a depressed state does not require financial investments and trips to a specialist. Sometimes it’s enough just to leave the house and go for a walk.

Social networks and social opportunities. Most of the work in psychology related to social networks, study their influence on the emotional state of a person: for example, is a Facebook trigger Have a good mood or provoke depression. In the past year, studies have emerged that focus on how Facebook manages our relationships. On the one hand, social media seems to be a great tool to expand our communication capabilities, surpassing the so-called Dunbar number - the number of permanent social connections that a person can maintain. But no: according to scientists, the Dunbar number is still in force, and our brain is able to control no more than 150 relationships (that is, to know and remember character traits and other characteristics of a person). So the expansion of social connections thanks to social networks is rather conditional - no matter how many “friends” you have, your brain is able to “make friends” only with a narrow circle.

Sticker reminders are still the most effective. No new technology will replace the usual reminders for us, written on a piece of paper and fixed somewhere in plain sight, say scientists who have devoted an entire study to this topic. Today, our life is becoming richer and more intense, so such practical knowledge, confirmed by scientific experiments, is simply necessary.