This post is for those who feel sad and despondent at the thought of going to the gym or jogging, who most like to sit at the computer, and want to lose a few pounds at the same time. Of course, nothing comes for nothing, and in order to lose weight without getting up from your favorite computer chair, you will have to do something, namely, think.
Scientists from a Canadian university conducted experiments on students, measuring the number of calories that the brain consumes. Three groups of students received different tasks that had to be completed for 1.5 hours. One group did nothing, the second group memorized texts from paper, and the third group worked at the computer. As a result, the group that memorized texts from books spent 200 kcal more than the idle students, and those who worked at the computer burned as much as 250 kcal more.
Scientists have found that the brain consumes the most calories during concentration. During extreme concentration for 20 minutes, the brain is able to “eat” such an amount of energy that it would not have spent the entire day spent without mental activity. Therefore, it can be quite difficult to concentrate on anything for more than 20-25 minutes - the body is simply forced to conserve energy reserves.
How many calories can you burn by actively thinking?
In the absence of mental stress, the brain burns up to 400-500 kcal per day, and during vigorous activity its costs double. It is generally accepted that when a person strains his brain, he spends 1.5 kcal per minute, that is, 90 kcal per hour, and if the activity is unusual, his costs increase even more.
Another feature is that emotional experiences increase energy consumption by 10-20%, and intellectual activity accompanied by emotions by 30-40%. Scientists from the Research Institute of Physiology named after. PC. Anokhin conducted another experiment, during which the energy consumption of students during exams was measured. It turned out that three days before the exams, the student spent 750 kcal on intellectual activity, and during the exam - 1000-1100 kcal.
So, taking into account all of the above, we can advise lovers of a sedentary lifestyle the following:
Think more
Viewing public pages on social networks, cheerful correspondence with friends or toys (except for those genres where you need to use your brain) will not burn extra calories. To lose weight at the computer, you need to perform some kind of intellectual activity, for example, read difficult, interesting articles and books, solve some problems, solve crosswords. At the same time, it is advisable not to be distracted, to maintain concentration on the subject longer.
The longer you concentrate, the more calories you burn.
Move food away from the computer
During mental activity, the level of glucose, a substance that feeds brain cells, drops sharply in the body. To make up for losses after mental activity, a person really wants to eat. This does not mean that the body really needs additional calories, it just needs glucose.
Scientists believe that a cup of sweet tea will be enough to replenish losses and give the brain the necessary nourishment, so after your intellectual exercises, do not rush to eat chocolates or cook dumplings - sweet tea, and the feeling of hunger will go away.
Emotional experiences
Of course, you won’t be able to give yourself stressful exams every day, but you can still do something. For example, solve logic problems against time or play chess with someone. This adds an element of excitement to intellectual activity. More excitement, more emotions, more calories burned.
Something new
The part of the brain that is working consumes more energy, so energy consumption can be increased by alternately turning on different parts of the brain, that is, by solving multi-part tests or playing puzzle games.
Besides, the brain consumes more energy when solving non-routine tasks. If you are a humanist, try solving logical problems, remember the school course in geometry or algebra. In general, engage in new types of intellectual activity - this not only increases energy expenditure, but also helps develop the brain.
And finally, we can’t help but mention that simple walking burns 4 kcal per minute, so if you’re tired of thinking, go for a walk.
12.11.2015Yu. Nesterova
Source: http://www.scientificamerican.com/article/thinking-hard-calories/
Unlike physical exercise, brain workout is unlikely to require increased energy expenditure. However, believing that our brains are exhausted by active work can still cause us to feel tired.
Updated 07/04/2019 17:07
From October to June, they crawl out of classrooms, classrooms and gyms, their eyes squinting in the sunlight, their fingers fumbling for the power button on cell phones that have been silent for four hours straight. Some of them raise their hand to their forehead, as if trying to relieve a headache. Others freeze at the entrance to the parking lot, unable to decide where to go next. They are completely exhausted, but not due to strenuous physical activity. Most likely, these students have just taken the SAT (Scholastic Aptitude Test). “I was fast asleep as soon as I got home,” says Ikra Ahmad, who was interviewed for an article about the “SAT hangover” published on The Local blog of the New York Times.
Temporary depletion of mental activity is a real and common phenomenon. It is important to note that it is different from chronic fatigue syndrome, which is associated with regular sleep disturbances and some medical disorders. Mental fatigue is felt daily, on a subconscious level. Naturally, intense mental activity and increased concentration require more energy than normal brain function. Just as vigorous physical exercise tires out our bodies, intellectual exertion should drain our minds.
But according to recent scientific research, the popular view of mental exhaustion is too simplistic. The brain constantly absorbs energy in enormous quantities for an organ of its size, regardless of whether we are taking integrals or clicking on the weekly top 10 funny cat photos. And although the activation of neurons requires an increased supply of blood, oxygen and glucose, local bursts of energy consumption are a trifle compared to the natural gluttony of the brain itself. That is, in most cases, short periods of additional mental effort require only a slight increase in brain power compared to its normal state, nothing more. However, in most laboratory experiments, volunteers were not assessed after hours of mental acrobatics. But something must explain the feeling of mental exhaustion, even if the physiology of this process is different from the mechanism of accumulation of physical fatigue. The easiest way to think is that our brains expend so much energy that it is enough to make us sluggish.
Brain power
Although the average adult human brain weighs about 1.4 kg, that is, only 2% of the total body weight, it accounts for 20% of the total resting metabolic rate (RMR), then is from the total amount of energy that our body expends in one very “lazy” day without much activity. RMR varies from person to person and depends on age, gender, physical parameters and health status. Assuming an average RMR of 1300 kilocalories, then the brain consumes 260 kilocalories just to maintain itself. This is 10.8 kilocalories per hour or 0.18 kilocalories per minute. (For comparison, see Harvard Medical School's chart on calorie intake during different activities.) Minimal mathematical calculations allow you to convert this number into a measure of power:
- Metabolic rate (RMR): 1300 kilocalories, or kcal, as food
- 1300 kcal in 24 hours = 54.16 kcal per hour = 15.04 cal per second
- 15.04 calories per second = 69.23 J/sec = about 63 Watts
- 20 percent of 63 watts = 12.6 watts.
Thus, a typical adult brain requires 12 watts to operate—about a fifth of the power required to operate a standard 60-watt light bulb. Compared to other organs, the brain seems gluttonous; but it is surprisingly efficient compared to man-made electronic devices. IBM's Watson, the supercomputer that won the game show Jeopardy!, depends on ninety IBM Power 750 servers, each consuming about a thousand watts.
Energy is supplied to the brain through the blood vessels in the form of glucose, which is transported across the blood-brain barrier and used to produce adenosine triphosphate (ATP), the main energy currency inside cells, produced chemically. Experiments in both animals and humans have shown that when neurons in a particular area of the brain fire, local capillaries dilate to deliver more than normal blood with extra glucose and oxygen. This reaction makes it possible to visualize the process: functional magnetic resonance imaging (MRI) is based on the unique magnetic properties of blood flowing through the vessels towards and from activated neurons. Research has confirmed that dilated blood vessels provide an influx of additional glucose, which brain cells greedily absorb.
Following the logic of these findings, a number of scientists have put forward the following theory: if the activation of neurons requires additional glucose, then especially difficult puzzles should lower blood glucose levels, and in addition, foods rich in carbohydrates should increase performance in solving such problems. However, although many studies have confirmed these assumptions, in general the results vary and in most cases changes in glucose levels range from minor to small. In a Northumbria University study, for example, volunteers who completed a series of verbal and numerical tasks showed a greater drop in blood glucose levels than people who simply pressed keys. In the same study, a sweet drink improved performance on one task but had no effect on the others.
At the University of Liverpool. John Moores volunteers took two versions of the Stroop task, which required them to determine the ink color of a printed word without reading the word itself. In one version, the color of the word and its meaning were the same: “blue” was printed in blue ink; a more complex version offered the word “blue” printed in green or red ink. Volunteers who performed the more difficult task experienced a greater drop in blood glucose levels, which the researchers interpreted as a result of increased mental effort. Some studies have shown that people who are bad at certain tasks put in more mental effort and use more glucose, but on the other hand, the more skilled you are in a given area, the more efficient your brain is and the less glucose it needs. To complicate matters, at least one study suggests that, on the contrary, more advanced brains require more energy.
Not just carbs
The unsatisfactory and mixed findings from studies on the role of glucose highlight that energy use in the brain is not simply a matter of mental effort draining the body of available energy. Claude Messier from the University of Ottawa has analyzed many similar studies. They couldn't convince him that performing any cognitive task changed glucose levels in the brain or blood.
In theory, yes, solving a more complex mental task requires more energy because it generates more neural activity, he explains. “But when people solve one problem, you don’t see a significant increase in glucose consumption by a significant percentage of the total level. The basal level itself requires a lot of energy - even in slow-wave sleep with minimal brain activity, the basal level of glucose consumption remains quite high." Most organs do not require much energy to maintain their “housekeeping” in a basic state. But the brain must maintain certain concentrations of charged particles in an active state to pass through the membranes of billions of neurons, even when they are not in an excited state. And since such support is constantly required and is expensive for the brain, it usually has the energy necessary to perform small additional tasks.
The authors of other reviews came to similar conclusions. Robert Kurzban of the University of Pennsylvania points to research showing that moderate exercise improves people's ability to concentrate. In one study, for example, children who walked for 20 minutes on a treadmill performed better on an academic achievement test than children who quietly read before an exam. If mental effort and performance were directly related to the level of available glucose, then children who were active and burned more energy in the process would perform worse than their peers who were at rest.
The relationship between energy intake and mental task difficulty "is weak and appears to be influenced by individual differences in effort, commitment, and available resources, which may be related to variables such as age, personal characteristics, and glucose metabolism," he writes. Leigh Gibson from the University of Rowehampton in a review of carbohydrates and mental performance.
Both Gibson and Messier conclude that when a person has trouble keeping glucose levels within normal limits or is restricting food for a long period of time (such as fasting), a sweet drink or food may improve brain performance on certain memory tasks. . But for most people, the body easily provides the small extra glucose that the brain needs during the extra mental effort.
Body and mind
If complex cognitive tasks require only a small increase in brain fuel than normal, then how do we explain the feeling of mental exhaustion after taking the SAT or a similarly grueling mental marathon? Alternatively, maintaining a continuous state of focus or navigating a given mental space for several hours does burn up enough energy to leave you feeling drained. However, the researchers did not confirm this version, because they simply did not try to create sufficiently harsh conditions for their volunteers. In most experiments, participants perform a single task of moderate difficulty, with completion times rarely exceeding one to two hours. "Maybe if we load more of them and force people to do things they're bad at, we'll get more accurate results," Messier said.
No less important than the duration of mental stress is the person’s attitude towards it. Watching a compelling biopic with a twisted plot activates many different parts of the brain for a good two hours, but audiences don't usually crawl out of the theater complaining of mental exhaustion. Some people regularly curl up with a novel written in such a neat font that others would throw it across the room in frustration. Completing a difficult crossword puzzle or solving Sudoku on a Sunday morning usually doesn't kill the ability to focus for the rest of the day—in fact, some claim it even sharpens their mind. In short, in ordinary life, intellectual activity gives people pleasure and invigoration without causing them to suffer from mental exhaustion.
It appears that fatigue is much more likely to set in as a result of sustained mental effort that we put in without expecting pleasure—like a required SAT—especially if we expect the test to exhaust our brains. If we think an exam or assignment will be difficult, it often is. Research has shown that something similar happens when people exercise: much of the physical exhaustion is in our heads. In related studies, volunteers who rode an exercise bike after taking a 90-minute computer-based mental alert test quit pedaling out of exhaustion earlier than participants who watched emotionally neutral documentaries before exercising. And although the attention tests didn't consume much more energy than watching movies, volunteers reported feeling less energetic. This feeling was strong enough to reduce their physical performance.
In the specific case of the SAT, there is something that goes beyond pure mental effort and probably contributes to the post-test stupor - stress. After all, the brain does not operate in a vacuum. Other organs also burn energy. Taking an exam that determines where a person will spend the next four years is itself a nerve-wracking enough event to release stress hormones into the bloodstream that cause sweating, an increase in heart rate, and causing one to squirm and assume awkward positions. The SAT and other similar tests are not only mentally grueling - they are also physically draining.
According to a small but revealing study, low-stress intellectual tasks also change our emotional state and behavior, even if they have little effect on brain metabolism. Fourteen female Canadian college students either sat idle or took a battery of computer-based attention and memory tests 45 minutes before a buffet-style feast. The students who exercised their brains ate 200 more calories than the students who relaxed. The blood glucose levels of the students taking the tests also fluctuated more than those of the students who were just sitting - no sequence of fluctuations could be identified. However, levels of the stress hormone cortisol were significantly higher in students whose brains were busy, as were their heart rates, blood pressure and self-reported anxiety levels. It's highly likely that these students weren't eating more because their exhausted brains needed extra fuel; rather, they simply ate away the stress with food.
Messier offered the following explanation for everyday bouts of mental fatigue: “My basic hypothesis is that the brain is a lazy fool,” he says. - It’s hard for him to focus on one thing for quite a long time. It is possible that maintaining a state of concentration leads to certain changes in the brain that cause it to avoid such states. It's maybe a kind of timer that says, “Okay, now you've done it.” Maybe the brain just doesn't like working so hard and for so long."
Jabr F. Does Thinking Really Hard Burn More Calories? Scientific American. July 18, 2012. URL: http://www.scientificamerican.com/article/thinking-hard-calories/
Scientific Research, Psychology/Motivation, Physiology
The human brain, even in a state of relative rest and sleep, consumes an unusually large amount of energy - 16 times more than muscle tissue (calculated per unit mass). “The brain, having a mass of no more than 1.5-2% of body weight, consumes 25% of all energy. At the same time, one of the most energy-consuming operations is concentration. A person is not able to maintain attention at a consistently high level for more than 20-25 minutes, because during this time the brain “eats” as much glucose as it would not have consumed in a day of relative rest. So tasks for attention and reaction, and even in a situation of time pressure, can squeeze out all the energy,” Igor Lalayants, candidate of biological sciences, an employee of the Institute of Neurosurgery of the Russian Academy of Medical Sciences, told RBC daily. - The need for energy decreases only during sleep, because... The synchronization of the left and right hemispheres increases and the brain does not have to waste energy on “coordinating” their work. Neurons also reduce energy consumption with age, which slows down the synthesis of protein molecules and, as a result, deteriorates the ability to remember.” In an adult, the share of cerebral metabolism from the total energy needs of the body is 9% during sleep and 20-25% during intense intellectual work, which is significantly more than in other primates (8-10%), not to mention other mammals ( 3-5%). So, just to maintain necessary vital functions, transmit nerve signals and reproduce basic operations, the human brain on average needs about 400-500 kcal. Meanwhile, according to the most conservative estimates, the energy expenditure of the brain in an active state more than doubles. “The part of the brain that is stressed the most consumes the most energy. Therefore, when solving multi-part tests and puzzles, where all types of thinking are alternately involved, energy consumption increases sharply. You will have to spend more calories on unusual tasks. So, if you force a humanities student to solve a geometry problem, the energy consumption of his brain will increase significantly. However, not everyone can bring themselves to the point of physical exhaustion with mental exercises. As a rule, scientists, mathematicians, and chess players have such a reaction to mental work,” explained Alexander Revishchin, candidate of biological sciences, senior researcher at the Institute of Developmental Biology of the Russian Academy of Sciences. In addition, intellectual work is certainly accompanied by activation of the nervous system and, under the influence of emotional experiences, energy costs increase by 10-20%. And unusually large intellectual loads, coupled with the stress that accompanies any exam or testing, according to the Russian Academy of Medical Sciences, increase the body’s energy consumption by 30-40%. Thus, scientists from the Research Institute of Normal Physiology named after P.K. Anokhin RAMS calculated the energy consumption of 75 students a few days before the exam and directly during testing. It turned out that the need for calories increased as the exams approached, and if three days before day “X” the student spent approximately 750 kcal in excess of the basal metabolism, then on the day of the exam - 1000-1100 kcal.
All of our organs burn calories when they perform their functions, right? So, since the brain is an organ, thinking burns calories, and thinking harder burns more calories?
Remember in cartoons, when the hero thinks, a large amount of steam comes out of his ears? Okay, a bit of an exaggeration, but a major shake-up does happen there when we make a mental effort. The brain burns a lot of calories at rest, and from external signs we can easily conclude that concentration contributes to the use of energy for potential actions. The reality, however, is more complex, and, in my opinion, much more interesting.
Our brain makes up only 2 percent of our total body weight, but consumes approximately 20 percent of our total caloric intake. The percentage is even higher in children whose brains are still developing. The average newborn's brain uses about 75 percent of its available energy, an 11-year-old's uses one-third, and the average adult's brain uses about 75 percent of its available energy.- about 20 watts.
About 60 - 80 percent of the brain's energy is used for "neural signaling" - I think that's what ordinary people who devote their lives to repairing and replenishing supplies call it. Just like any physical matter, the brain “burns” glucose, which reacts with oxygen to produce “fuel.” Glucose and oxygen are carried by the blood, so during intense mental activity we may experience an increase in cerebral blood flow and an increase in the use of glucose and oxygen, and as a result, more energy consumption.
And this is what scientists discovered in the process of their research:
In 1878, an Italian scientist working with a patient with a skull injury discovered that the subject's brain pulsed faster when the subject solved arithmetic problems.
In a 1995 study, glucose consumption and cerebral blood flow of volunteers taking a card sorting test increased by 12 percent.
A 1987 study that asked volunteers to think about an afternoon walk increased their brain metabolism by 10 percent.
A 1992 study of Tetris players found that if they played the game 5 days a week for a month or two, the brain's glucose consumption increased significantly, suggesting that their thinking became more efficient with practice.
However, upon closer examination, not everything is simple. For example, back to the card sorting test, while cerebral blood flow and glucose consumption increased, oxygen use — no, this means that there was no increase in combustion - the brain did not "burn" noticeably more "fuel". This is exactly what neuroscientists are still trying to figure out. Cerebral blood flow does not increase rapidly enough to provide an immediate increase in energy intake; researchers now speculate that blood flow speed increases to cool the brain or carry away waste products. The breakdown of glucose increases, but without combustion (oxidation) the energy jump is small, perhaps less than 1 percent.
However, the fact remains that the brain consumes a disproportionate share of energy, most of which is spent on thinking. That said, some brain scientists say we should have a different view of what's going on there. Previously, it was believed that the brain responded extremely passively to external stimuli. Now that we understand that external events do not influence changes in the brain's energy consumption as much, a different picture emerges: most of our mental activity occurs strictly in our heads.
"So what", - you say. Give me a sec. Neurologist Marcus Raichl, writing for Science magazine, calls the brain a "Bayesian inference engine designed to make predictions about the future." In other words, the brain itself creates the memories, conclusions and desires that make up our personality. All this energy goes into feeding the team of “pipe-smoking dwarfs” between our ears who take in all our feelings, think about them, and organize our next actions.
And these dwarfs work quite efficiently. The human brain contains approximately 86 billion neurons, occupying a volume comparable to a grapefruit (gorillas and orangutans, the closest brain-sized primates to us, have about 33 billion). The most powerful electronic brain in the world today is a supercomputer. Titan, located at Oak Ridge National Laboratory in Tennessee, which can perform 17.6 quadrillion floating point operations per second or 17.6 petaflops. Bearing in mind that the mind and computers are not exactly comparable, the computing power of the human brain is said to be 1 exaflop (57 times that of a computer).
Of course, in terms of pure computing power, machines will undoubtedly surpass humans, some believe within a decade. But let's take this to the future. Remember, the adult brain uses approximately 20 watts, which means its performance is approximately 50 petaflops per watt. The performance of a typical supercomputer is 2.5 gigaflops per watt. This is 1/20 millionth the efficiency of the brain. In other words, a supercomputer Titan – 8.2. a mega-watt liquid-cooled monster the size of a large suburban home. A more powerful human model runs on Cheerios cereal that can fit in a hat.
In contact with
1. The brain, like muscles, the more you train it, the more it grows. The brain of an average adult man weighs 1424 g, with old age the brain mass decreases to 1395 g. The largest female brain by weight is 1565 g. The record weight of the male brain is 2049. The brain of I. S. Turgenev weighed 2012. The brain evolves: in 1860 year, the average weight of the male brain was 1372 g. The smallest weight of a normal, non-atrophied brain belonged to a 31-year-old woman - 1096 g. Dinosaurs, reaching 9 m in length, had a brain the size of a walnut and weighing only 70 g.
2. The most rapid development of the brain occurs between the ages of 2 and 11 years.
3. Regular prayer reduces the breathing rate and normalizes brain wave vibrations, promoting the body’s self-healing process. Believers go to the doctor 36% less often than others.
4. The more educated a person is, the lower the likelihood of brain diseases. Intellectual activity causes the production of additional tissue to compensate for the disease.
5. Engaging in unfamiliar activities is the best way to develop your brain. Connecting with others who are intellectually superior to you is also a powerful way to develop your brain.
6. Signals in the human nervous system reach speeds of 288 km/h. By old age, the speed decreases by 15 percent.
7. The world's largest brain donor is the monastic order of Sisters Educators in Mankato, Minnesota. The nuns donated about 700 brain units to science in their posthumous wills.
8. The highest level of intellectual development (IQ) was demonstrated by Marilyn Much Vos Savant from Missouri, who at the age of ten already had the average IQ for 23 year olds. She managed to pass the most difficult test for entry into the privileged Mega Society, which includes only about three dozen people with such a high IQ, which is found in only 1 person in a million.
9. The Japanese have the highest average national IQ in the world -111. 10 percent of Japanese have a score above 130.
10. Superphotographic memory belongs to Creighton Carvello, who is able to remember the sequence of cards in six separate decks (312 pieces) at once. Typically, in our lives we use 5-7 percent of our brain capacity. It’s hard to imagine how much a person would have accomplished and discovered if he had used at least as much more. Scientists have not yet figured out why we need such a safety margin.
11. Mental work does not tire the brain. It has been discovered that the composition of the blood flowing through the brain remains unchanged throughout its active activity, no matter how long it lasts. At the same time, blood that is taken from the vein of a person who has worked all day contains a certain percentage of “fatigue toxins.” Psychiatrists have found that the feeling of brain fatigue is determined by our mental and emotional state.
12. Prayer has a beneficial effect on brain activity. During prayer, a person’s perception of information goes without thinking processes and analysis, i.e. a person escapes reality. In this state (as with meditation), delta waves appear in the brain, which are usually recorded in infants in the first six months of his life. Perhaps it is this fact that influences the fact that people who regularly perform religious rites get sick less often and recover faster.
13. For proper brain function, you need to drink enough fluid. The brain, like our entire body, consists of approximately 75% water. Therefore, to keep it healthy and in working condition, you need to drink the amount of water required by your body. Those who are trying to lose weight with the help of pills and tea, which expel water from the body, should be prepared for the fact that at the same time as they lose weight, they will also lose brain performance. Therefore, they should do as they should - take any pills prescribed by the doctor.
14. The brain wakes up longer than the body. A person’s intellectual abilities immediately after waking up are lower than after a sleepless night or in a state of moderate intoxication. It is very useful, in addition to a morning jog and breakfast, which enhance the metabolic processes occurring in your body, to do a little brain exercise. This means that you shouldn’t turn on the TV in the morning, but rather read something a little or solve a crossword puzzle.
15. It is easier for the brain to understand the speech of men than women. Male and female voices affect different parts of the brain. Women's voices are more musical, sound at higher frequencies, and the frequency range is wider than that of men's voices. The human brain has to “decipher” the meaning of what a woman is saying, using its additional resources. By the way, people suffering from auditory hallucinations more often hear men’s speech.
16. The brain consumes more energy than all other organs. It makes up only 2% of the total body weight, but takes about 20% of the energy produced by the body. Energy supports normal brain function and is transmitted by neurons to create nerve impulses.
17. The brain contains approximately 100 billion neurons (cells that generate and transmit nerve impulses), which is about 16 times more than there are people on Earth. Each of them is connected to 10,000 other neurons. By transmitting nerve impulses, neurons ensure continuous functioning of the brain.
18. People only use 10% of their brain. It is a myth. Even though not all the secrets and capabilities of the brain have been revealed, it is stupid to say so - the brain always uses as many resources as it needs at the moment. Saying that we use 10% of our brain is the same as saying that we use one percent of the radio's capabilities - we listen to only one wave, but there are a hundred more in the range.
19. Every minute, 750 milliliters of blood passes through the brain, which is 15-20 percent of the total blood flow.
20. The brain consumes 25 watts of energy while awake. This amount is enough for a small light bulb.
