March 22, 1995 cosmonaut Valery Polyakov returned from space after 438 days of flight. This record of duration has not yet been broken. It became possible as a result of constantly conducted in-orbit studies of the influence of cosmic factors on the human body.
1. Overloads at launch and landing
Perhaps, it was Polyakov who, like no one else, was prepared to stay in orbit for a year and a half. And not because he allegedly has phenomenal health. And he was engaged in pre-flight preparation no more than others. Simply Polyakov, being a professional doctor - candidate of medical sciences, who worked at the Institute of Biomedical Problems of the Russian Academy of Sciences, like no one else in the cosmonaut corps knew the “human structure”, the body’s reactions to destabilizing factors and methods of their compensation. What are they like?
At start space ship Overloads range from 1g to 7g. This is extremely dangerous if the overload acts on a vertical axis, that is, from head to feet. In this position, a person even with an overload of 3g, acting for three seconds, there are serious violations of peripheral vision. If these values \u200b\u200bare exceeded, changes can become irreversible, and a person is guaranteed to lose consciousness.
Therefore, the chair in the ship is placed so that the acceleration acts in a horizontal plane. Also, the astronaut uses a special compensation suit. This makes it possible to maintain normal cerebral circulation with prolonged overloads of 10g, and short-term - up to 25g. Extremely important is also the rate of rise of acceleration. If it exceeds a certain limit, then even slight overloads can be detrimental to the astronaut.
After a long stay in orbit, the disheveled body suffers the overloads that occur during landing, much harder than at launch. Therefore, the astronaut a few days before landing is prepared according to a special technique involving physical exercises and medications. During landing, the orientation of the ship in dense layers of the atmosphere is of such great importance that the axis of the load is horizontal. During the first space flights, it was not possible to achieve proper stabilization of the ship, and therefore astronauts sometimes lost consciousness during landing.
2. Weightlessness
Weightlessness is a much more difficult test for the body than overload. Because it acts for a long time and continuously, causing changes in a number of vital functions in the human body. So, weightlessness puts central nervous system and receptors of many analyzer systems (vestibular apparatus, muscular-articular apparatus, blood vessels) in unusual operating conditions. As a result, blood flow slows down, blood accumulates in the upper body.
The "meanness" of weightlessness is that adaptive processes in physiological systems, the degree of their manifestation is practically independent of individual features organism, but only on the length of stay in zero gravity. That is, no matter how a person prepares for it on earth, no matter how powerful his body may be, this has little effect on the adaptation process.
True, a person quickly gets used to weightlessness: dizziness and other negative phenomena stop. The astronaut “eats” the fruits of zero gravity, having returned to the earth.
If in orbit you do not use any methods of opposing the destructive effect of weightlessness, then in the first few days the landing astronaut has the following changes:
1. Violation of metabolic processes, especially water-salt metabolism, which is accompanied by relative dehydration of tissues, a decrease in the volume of circulating blood, a decrease in the content of a number of elements in tissues, in particular potassium and calcium;
2. Violation of the oxygen regime of the body during physical exertion;
3. Impairment of support vertical pose in statics and dynamics; a feeling of heaviness in parts of the body (surrounding objects are perceived as unusually heavy; there is a tendency to dosing muscle effort);
4. Violation of hemodynamics during the work of medium and high intensity; possible fainting and fainting conditions after transition from horizontal position in vertical;
5. Decreased immunity.
In orbit, a whole range of measures is used to combat the body-destroying effect of weightlessness. Increased consumption potassium and calcium. Negative pressure applied to the lower half of the body for the outflow of blood. Bar compensating linen. Muscle electrical stimulation. Dosed medication. Training on a treadmill and other simulators.
3. Hypodynamia
A treadmill and various muscle training equipment are also used to combat physical inactivity. In orbit, it is inevitable, since movements in zero gravity require much less effort than on earth. And having returned to the earth even after daily exhausting trainings, the astronauts observed a decrease muscle mass. Besides exercise stress beneficial effect on the heart, which, as you know, is also a muscle.
4. Radiation
The effect of this factor on the human body is well understood. The World Health Organization has developed radiation dose standards that exceed health hazards. For cosmonauts, these standards do not apply.
It is believed that a person can undergo fluorography no more than once a year. Moreover, he receives a dose of 0.8 mSv (millisievert). The astronaut receives a daily dose of up to 3.5 mSv. However, by the standards of space medicine, such a radiation background is considered acceptable. Since to a certain extent it is neutralized medically. The daily dose of radiation is not a constant. Each astronaut has an individual dosimeter, which counts the millisieverts accumulating in the body. For a year in space, you can get from 100 to 300 mSv.
“Of course, this is not a gift,” says Vyacheslav Shurshakov, head of the laboratory of methods and tools for space dosimetry at the Institute of Biomedical Problems of the Russian Academy of Sciences, “but this is the specificity of the cosmonaut profession.”
At the same time, the annual threshold dose is 500 mSv. That 25 exceeds the threshold for employees of nuclear power plants, which is 20 mSv.
Well, the total dose, after which the astronaut is not allowed to fly, is 1000 mSv. At the same time when Gagarin flew, this figure was 4000 mSv. The closest to the threshold was Sergei Avdeev, with a total of 747 days flying. The dose he received is 380 mSv.
Photo ITAR-TASS / Albert Pushkarev
Museum Scientific Advisor "Experimentanium" and physiologist Anton Zakharov tells what happens to the body of a person while he is flying into space and while he is there. The network edition M24.ru provides a full text version of the lecture.
We will talk about what happens to a person on a space station a little later, but for now we need to deal with the difficulties that await a person when taking off into space. The first difficulty he faces is what? I guess you guess?
- Weightlessness.
No, weightlessness a bit later.
- Overload.
Overload, absolutely correct. Here is a small tablet, a tablet of sensations that arise in a person when he experiences overload. In general, what is overload, where does it come from? Do you think there are ideas? You are welcome.
- A plane or a space station begins to rise, while a person begins to deviate in the other direction, an overload occurs.
And why is it called overload?
- Probably because a person feels uncomfortable.
In fact, you and I are just very much used to living with a load. When we are with you, as now - you are sitting, I am standing - on our planet Earth, we are attracted to the Earth, and our blood is attracted to the Earth more than all other parts of our body, because it is liquid. It is as if going to Earth. And the rest of our body is harder, so they are slightly less attracted to the Earth, but their shape is more constant. And we are very well adapted to this load, and when we lose this load, a not very pleasant sensation will occur, which I will talk about later.
But before falling into weightlessness, where this load is not present, a person experiences overloads, that is, an excessive effect of gravity. With a double overload - overload of 2 g - the person’s body becomes heavier, his face sags a little, it’s hard to stand up, of course, you need to lift not 50-60-70 kg, which you usually weigh, but twice as much. With triple overload, it is already impossible for a person to stand, and the person’s digital vision is turned off first, because the cells that are responsible for digital vision consume a lot of energy. At 4.5 g, vision is completely turned off, our retina is already lacking blood, then it is impossible to raise an arm or leg. And at 12 g, most people lose consciousness. All that I say now concerns overloads not instantaneous, but which last for some time, at least 10-20-30 seconds, instantaneous overloads are stronger. Do you think such overloads in everyday life can be met without going up into space?
An overload of 4.5 g can be experienced without taking off into space? Actually, it’s usually around 1.5, but if you ride the rides, just 3-4 g can be experienced. And so, it is clear that a person standing motionless, 1 g experiences; on the plane - somewhere around 1.5; a paratrooper who lands, somewhere around 2 g; at the time of opening the parachute for a very short time he experiences 10 g, that is, almost on the verge of loss of consciousness. At the same time, the astronauts who are flying now experience less - 3-4 g, they have these 8-12 - very strong overloads - no, they were tested only by the astronauts when they were building spacecraft, then it was 7-8 g, it was problem. Now everything is done so that it was easier to take off.
In fact, military pilots often experience the most intense overloads. At the time of the performance of some aerobatics, it’s quite possible to have 12 g, but for a short time, so they don’t lose consciousness - this is one time, and two - they are very trained, so it’s easier to handle. The maximum overloads allowed for health, even short-term ones, are about 25 g. If the overload is greater, even short-term, then the probability that a person will break his spine begins to approach 90%, and this, of course, is not very good.
We talked about ordinary overloads, the so-called positive overloads. We found that antigravity does not exist. And what do you think negative overloads can be? (But overload and gravity are slightly different concepts) And, indeed, there are negative overloads, if you just stand on your head, you will experience negative overload of -1 g, because the blood that usually rushes to the legs, and the parts of the body that usually press each other in one direction, they will begin to press against each other in the other direction, and blood will begin to flow to the head. This is quite a negative overload and, naturally, large negative overloads are also harmful to health, and they can also be experienced without flying into any space. They, for example, are experienced by bungee jumpers - what in English is called bungee jumping.
In fact, this bungee jumping ... Firstly, I’m even scared to look at photographs, and secondly, this is a very interesting ritual. Does anyone know where it came from? The fact is that the Indians of the Vanuatu tribe in South America thus consecrated boys into men. They climbed a tall tree, took some kind of strong vine, tied it to her feet, and the teenager had to jump with this vine vine, not reaching the ground a meter or two. And if he calmly stood, he became a man. When students of Oxford found out about this in the 70s of the 20th century, they were wildly delighted and decided that such a tradition should be repeated. But they decided that the first jump should be full of solemnity, and dressed up in tailcoats. Now bungee jumpers are informal people, and the first jumpers jumped in suits, it was pretty enough.
We talked with swamis about overloads, this is not the only problem that astronauts experience. The astronauts took off, coped with the overloads, ascend into space, and then the first joys and first problems await them.
Well, joys, of course, when a person ascends into space, full of pants - this is understandable. And in astronauts, as in young children, this happens - and this is confirmed by biochemical studies - higher is the "hormone of happiness" in the blood than in ordinary people. And they can, in principle, be understood, a lot of cool things are happening there. Let's watch one video from the ISS. In principle, people have fun as they can, of course. It is not necessary to carry things with your hands; you can also carry them with your feet. Movements must be very accurately calculated, must be very accurate. This is how astronauts actually don’t wash their hands, it was shot specifically for the video, for the sake of these 10 beautiful seconds, then the astronauts will spend a lot of energy collecting these droplets one at a time. It just seems - wow, how cool they scattered, but they really scattered, now you need to collect them all, the problem is quite serious.
So, we roughly saw how cosmonauts live in space, now let's think what problems await them there. The first problem is that a person does not experience gravity there. Gravity do not experience including its balance organs. Where do we have balance organs, does anyone know?
- In the head, cerebellum?
In the ear. No, the cerebellum is the brain center that provides balance coordination, but this is not the sensitive part, but the sensitive part in our ear. The beautiful pebbles that are pictured here are otolith crystals, these are pebbles that are in our vestibular apparatus, its pouch, and when we turn our heads from side to side, they roll around inside our vestibular apparatus, so we understand that our head is turned relative to the rest of the body. These crystals are in these bags. What happens in space, in space, one simple thing happens, these pebbles begin, like all steel, to float inside the vestibular apparatus - a person crashes. On the one hand, his eyes tell him that he is still upright, everything is fine, and on the other hand, the balance organs say: I don’t understand what happened, I’m sausage in all directions, I don’t know what to do. There is a manifestation that resembles a cosmic illness - a seasickness. Then the same thing happens, the vestibular apparatus sways in different directions, and the eyes do not sway so much, and the body malfunctions, and the body begins to do what?
- Vomit.
It starts to vomit, and it starts to vomit in space just as well, but since this restructuring takes place in space much more sharply, almost all cosmonauts have a space sickness. True, not everyone is sick, but those who are sick are a dangerous thing. Because people usually experience bouts of space sickness at the moment when they have already docked to the space station and even in spacesuits. They begin to make their first movements, going to the space station, that is, they are in closed spacesuits and, laughing, laughing, but this is one of serious reasons the death of the astronauts, simply because the spacesuit is closed, and you can’t fly without a spacesuit. Why, I’ll tell you about this a little later.
Going further, another problem that awaits people in space is a decrease in the number of blood cells. Different reasons this has one of the reasons this: in space there is a decrease in bone tissue, and inside the bone tissue just blood cells are formed. Therefore, if the seeds become smaller, then the cells become smaller. In general, a rather unpleasant thing, especially unpleasant when the astronaut returns to Earth, and he needs to go through a period of adaptation back to the conditions on Earth. Among other things, he suffers a powerful lack of oxygen just because he lacks these blood cells that carry oxygen. Actually, more about bones. Why do bones collapse in space, you know? Any ideas?
- No load.
There is no load, it is absolutely true that our bones work normally, they must constantly receive some kind of load, you and I must constantly work. But we recall that working in space is not easy: there is no need, no opportunity. Since it weighs nothing, no matter what you do, you spend a lot less effort. And, despite the fact that the astronauts train all the time, they still can not experience the same level of physical activity as on Earth. Therefore, after 3-4 flights, bone problems begin, which, in particular, lead to osteoporosis when bone tissue is destroyed.
Another problem is blood again. I said that we are very well adapted to the load on Earth. How are we fit? We have excess blood, each adult has about 5 liters of blood. This is more than we need. Why do we need this excess? Because we are upright, and most of the blood remains in our legs, below our body, and not everything reaches our heads, so we need to store some excess so that there is enough blood and head. But gravity immediately disappears in space, and therefore this excess blood that was in the legs begins to urgently move somewhere throughout the body. In particular, it enters a person’s head and brain, as a result of which there are strokes, micro-strokes, because too much blood enters, and the vessels just burst. As a result of this, astronauts especially often run to the toilet in the first week, they just lose excess fluid, they lose about 20% of excess fluid in the first week of being in orbit.
Muscles also do not experience stress. Regardless of the size of the cargo, no matter how much it weighs on Earth, there will be no difficulty in transferring it in space. Therefore, astronauts, I have already said, are necessarily training in space. About this next video. Naturally, it makes no sense to lift gravity in space, you can try to run. Indeed, a person runs, only, pay attention, he is attached to a treadmill, because if he was not tied to a treadmill, he would simply fly away. Again, weights cannot be lifted, but springs can be unbent, and astronauts spend at least 4 hours a day in physical exercises. Cosmonauts, as you know, are the most prepared people, the most physically strong and persistent. And still, when they return from space, they, firstly, never in their life reach the shape that they were before the first flight, and secondly, even an approximate recovery after these loads takes about the same time as an astronaut was in orbit. That is, if he was there for half a year, he will be restored for half a year, they can’t even walk for the first few weeks. That is, their leg muscles almost atrophied, they have not used them for six months.
We go further, another problem associated with what the astronaut should breathe in space. The problem is two-sided: first of all, it is necessary to lift air or oxygen into orbit. What do you think is better to raise - air or oxygen, than we breathe with you?
- Oxygen.
Oxygen, here the Americans also thought that it was better to put pure oxygen into orbit, albeit a little rarefied. Although, in fact, pure oxygen is a pretty scary thing. Firstly, it is dangerous for the body, it is poison - in large quantitiesand secondly, it explodes very well. For the first few years, rockets filled with pure oxygen took off normally, and then at some point one spark ran, and there was no stone left from the spacecraft. After that, they decided to do just like cylinders with liquid air, just as the Soviet Union did. This is a difficult option, it is expensive but safe.
There is a second problem: when we breathe, we emit carbon dioxide. If there is too much carbon dioxide, the head starts to hurt, drowsiness appears, and at some point a person may lose consciousness and die from an excess of carbon dioxide. We emit carbon dioxide on Earth, and plants absorb it; in space, even if you take one or two plants with you, they won’t do the job, and you won’t take many plants with you because they are heavy and take up a lot of space. How to get rid of carbon dioxide? There is one special chemical substance that can absorb excess carbon dioxide, called lithium hydroxide, it is transported into space, it just absorbs excess carbon dioxide. One very interesting, such heroic story, the history of the Apollo 13 ship, is connected with this substance, I think adults remember this story.
Have children ever heard of the Apollo 13 ship? Have you heard, even shot such a film, what happened to this ship? He had a very unsuccessful flight, there were many different things there, we are interested in what happened with lithium hydroxide. The story is this: "Apollo 13" is not the first, not the second time flew to the moon, to explore the moon. Three people flew there, they had their own spaceship and a special capsule, which was supposed to be lounged, and two people who were supposed to go on the moon, do something there, and then return back on the capsule and fly to Earth. But somewhere on the 3rd day of the flight, an explosion suddenly occurred, and part of the main ship turned around, including damaging the life support system. In principle, this is not such a terrible problem, because the boat on which it was necessary to fly up to the Moon was intact, and it was quite possible to return to Earth on it. But there was a completely idiotic problem: the cans with lithium hydroxide that were stored on the boat and the cans with lithium hydroxide that were stored on the ship were different, they just had different inlets. And all the engineers in America who were associated with the project, and many engineers in the world, spent about a day doing what people usually do in the program Crazy Hands. They figured out how to use glue, scraps of newspapers, paper clips and what is on the ship to remake one exit to another so that people could fly back to Earth. They succeeded, thank God, and this ship (while it landed, also had many different problems), thank God, it landed normally.
We found out that people in space have problems when they are awake: blood is bad, muscles are bad, bones are bad, and so on and so forth. Sleeping in space is also bad. There are two reasons: the first reason is that no one turns off the lights at the space station, it must work all the time, all kinds of experiments are carried out there all the time. The work is very intense, so the astronauts sleep on shifts: first one, then others. It’s hard, if you sleep like that a day, two sleep, three, then it’s okay, but if you sleep like that for two or three weeks or a month, then restructuring in the body begins, and this is harmful. This is also harmful for us, because now many people in large cities live in the wrong light mode, because of this we suffer and do not even notice it. Another problem is that, since there is no attraction, and a person cannot lean on anything, this is a very important feeling, as psychologists have found out. In order to fall asleep, a person needs to lean against something and feel confident. Therefore, the astronauts put on special blindfolds under their knees and put on special blindfolds to create at least some kind of imitation of what pulls them somewhere. It doesn’t work out very well, but it turns out. There is a third problem that is already connected with carbon dioxide: while we are sleeping, we breathe and emit carbon dioxide, we are not moving, and carbon dioxide accumulates on the surface of our face. On Earth, it’s not scary, why?
- He moves all the time.
He really moves all the time, and why? Because there is a little breeze, but that’s not even the point. When we exhale carbon dioxide, we exhale it warm, and warm gas will rise up, because it is lighter than cold. In space, neither warm nor cold gas has weight, so the exhaled gas will accumulate over a person, and he will simply sleep in this cloud if nothing is done about it. But they really do something with it - and in space there are very powerful ventilation systems that accelerate carbon dioxide so that we can sleep peacefully. And these same ventilation systems filter the air from various infections and pathogens. Now they have learned to cope with this more or less, and at first the astronauts were very ill, because the quarantine was not strict enough, and getting infected in space was much easier. Because when we sneeze on Earth, what we sneezed on the ground and some kind of dust remains, we don’t directly breathe it. And if the astronaut sneezes, then everything that he sneezed remains in the air, so the probability of catching this infection is much higher, so everyone filters it. There really is a lot of dust from the astronauts, they still sneeze a lot, but they are already sick less, because the quarantine is more strict.
Another problem that awaits the astronauts is cosmic radiation. We on Earth are protected from cosmic radiation by an atmosphere that does not transmit radiation, in particular, the ozone layer is well protected from it. But there is no ozone layer in space, and astronauts experience increased radiation. This is dangerous, and it was feared for a very long time, until we checked how much radiation a person was experiencing there. He experiences about as much as the residents of those places that are located in granite rocks, for example. Granite rocks also emit a little radiation, about the same amount the astronaut receives. That is, the inhabitants of, say, Cornwall (this is in England), consider that the astronauts in this regard, even receive a little more radiation. And quite a lot of radiation is received by pilots and stewardesses of supersonic aircraft (Concord, for example), which fly at high altitudes.
But we hope that someday man will not only fly on space stations, and fly to Mars, to other planets. And in these cases, a threat awaits us, because usually space stations fly around the Earth - where the radiation field is not very strong. But around the Earth there are two "donuts" of powerful radiation fields through which you need to fly through to get to the Moon, Mars, and other planets. And there the radiation is very strong, and one of the problems sending to Mars now is the effect of radiation for several months. People may fly there, but they will fly very sick - this, of course, no one wants. So now they’re coming up with how to make both a light spacesuit and light lining of a spaceship, which would protect against radiation. Because, in principle, it is not difficult to protect yourself from radiation, you can impose lead on a ship and okay - we are protected from radiation, but lead is very heavy.
We talked about the cons, cons, cons. But there are not only cons when flying into space. When we fly into space (it’s not that big plus, it’s just very nice) we get a little higher. Under the influence of gravity, while we walk all day somewhere, our vertebrae press against each other, and most importantly, press on the intervertebral discs. They “flatten out” a little during the day, so a person is several centimeters higher in the morning than in the evening. If you haven’t tried, you can check at home. Why is it always advised to measure growth at the same time, because during the day it changes. So, in space, gravity does not work, so the astronauts grow a little, sometimes even too much. One astronaut grew by as much as 7 centimeters, he was very happy, he had already been there for many years, one problem - the suit did not grow, it was quite crowded. Now all the spacesuits are doing - 10 centimeters are left in case the astronaut grows up.
An interesting thing: in space, it turns out that regeneration processes are faster, wounds heal faster and even whole parts of the body can recover. Now there will be a video with a snail. Here, of course, accelerated shooting, in fact, this two weeks has grown approximately. On land, snails also regenerate, but worse. Why this happens is not clear. Why am I saying all this? I said already at the beginning: before our eyes in the near future the number of people who will fly into space will grow, and grow, and grow. Perhaps soon this will not be a topic for a popular science lecture, but a standard lesson at school: you will need to know what happens to a person when he simply decided to fly on an excursion into space. I very much believe that this will happen soon, and I hope that you also believe. If you have questions, please ask.
- Tell me, if there were overloads, the consciousness turned off, then how quickly does a person recover, comes to consciousness?
When consciousness is turned off, the system is the same as when a person faints. Someone immediately gets up, someone does not immediately, strongly affects someone, less of someone. In general, this, of course, is harmful. A person loses consciousness because he does not have enough oxygen to enter the bloodstream, which means that not enough oxygen enters the brain. As a result, some brain cells may begin to die, some more actively, some less active.
March 22, 1995 cosmonaut Valery Polyakov returned from space after 438 days of flight. This record of duration has not yet been broken. It became possible as a result of constantly conducted in-orbit studies of the influence of cosmic factors on the human body.
1. Overloads at launch and landing
Perhaps, it was Polyakov who, like no one else, was prepared to stay in orbit for a year and a half. And not because he allegedly has phenomenal health. And he was engaged in pre-flight preparation no more than others. Simply Polyakov, being a professional doctor - candidate of medical sciences, who worked at the Institute of Biomedical Problems of the Russian Academy of Sciences, like no one else in the cosmonaut corps knew the “human structure”, the body’s reactions to destabilizing factors and methods of their compensation. What are they like?
At the launch of the spacecraft, the overloads range from 1g to 7g. This is extremely dangerous if the overload acts on a vertical axis, that is, from head to feet. In this position, a person even with an overload of 3g, acting for three seconds, there are serious violations of peripheral vision. If these values \u200b\u200bare exceeded, changes can become irreversible, and a person is guaranteed to lose consciousness.
Therefore, the chair in the ship is placed so that the acceleration acts in a horizontal plane. Also, the astronaut uses a special compensation suit. This makes it possible to maintain normal cerebral circulation with prolonged overloads of 10g, and short-term ones up to 25g. Extremely important is also the rate of rise of acceleration. If it exceeds a certain limit, then even slight overloads can be detrimental to the astronaut.
After a long stay in orbit, the disheveled body suffers the overloads that occur during landing, much harder than at launch. Therefore, the astronaut a few days before the landing is prepared according to a special technique, involving physical exercises and medications. During landing, the orientation of the ship in dense layers of the atmosphere is of such great importance that the axis of the load is horizontal. During the first space flights, it was not possible to achieve proper stabilization of the ship, and therefore astronauts sometimes lost consciousness during landing.
2. Weightlessness
Weightlessness is a much more difficult test for the body than overload. Because it acts for a long time and continuously, causing changes in a number of vital functions in the human body. Thus, weightlessness puts the central nervous system and receptors of many analyzer systems (vestibular apparatus, muscular-articular apparatus, blood vessels) in unusual functioning conditions. As a result, blood flow slows down, blood accumulates in the upper body.
The “meanness” of weightlessness is that adaptive processes in physiological systems, the degree of their manifestation, practically does not depend on the individual characteristics of the organism, but only on the length of stay in zero gravity. That is, no matter how a person prepares for it on earth, no matter how powerful his body may be, this has little effect on the adaptation process.
True, a person quickly gets used to weightlessness: dizziness and other negative phenomena stop. The astronaut “eats” the fruits of zero gravity, having returned to the earth.
If in orbit you do not use any methods of opposing the destructive effect of weightlessness, then in the first few days the landing astronaut has the following changes:
1. Violation of metabolic processes, especially water-salt metabolism, which is accompanied by relative dehydration of tissues, a decrease in the volume of circulating blood, a decrease in the content of a number of elements in tissues, in particular potassium and calcium;
2. Violation of the oxygen regime of the body during physical exertion;
3. Violation of the ability to maintain an upright posture in statics and dynamics; a feeling of heaviness in parts of the body (surrounding objects are perceived as unusually heavy; there is a tendency to dosing muscle effort);
4. Violation of hemodynamics during the work of medium and high intensity; possible fainting and fainting states after a transition from horizontal to vertical;
5. Decreased immunity.
In orbit, a whole range of measures is used to combat the body-destroying effect of weightlessness. Increased intake of potassium and calcium. Negative pressure applied to the lower half of the body for the outflow of blood. Bar compensating linen. Muscle electrical stimulation. Dosed medication. Training on a treadmill and other simulators.
3. Hypodynamia
A treadmill and various muscle training equipment are also used to combat physical inactivity. In orbit, it is inevitable, since movements in zero gravity require much less effort than on earth. And returning to the ground even after daily exhausting workouts, the astronauts observed a decrease in muscle mass. In addition, physical activity has a beneficial effect on the heart, which, as you know, is also a muscle.
4. Radiation
The effect of this factor on the human body is well understood. The World Health Organization has developed radiation dose standards that exceed health hazards. For cosmonauts, these standards do not apply.
It is believed that a person can undergo fluorography no more than once a year. Moreover, he receives a dose of 0.8 mSv (millisievert). The astronaut receives a daily dose of up to 3.5 mSv. However, by the standards of space medicine, such a radiation background is considered acceptable. Since to a certain extent it is neutralized medically. The daily dose of radiation is not a constant. Each astronaut has an individual dosimeter, which counts the millisieverts accumulating in the body. For a year in space, you can get from 100 to 300 mSv.
“Of course, this is not a gift,” says Vyacheslav Shurshakov, head of the laboratory of methods and tools for space dosimetry at the Institute of Biomedical Problems of the Russian Academy of Sciences, “but this is the specificity of the cosmonaut profession.”
At the same time, the annual threshold dose is 500 mSv. That 25 exceeds the threshold for employees of nuclear power plants, which is 20 mSv.
Well, the total dose, after which the astronaut is not allowed to fly, is 1000 mSv. At the same time when Gagarin flew, this figure was 4000 mSv. The closest to the threshold was Sergei Avdeev, with a total of 747 days flying. The dose he received is 380 mSv.
Photo ITAR-TASS / Albert Pushkarev
Overload - the ratio of the absolute value of linear acceleration caused by non-gravitational forces to the acceleration of gravity on the Earth's surface. Being a ratio of two forces, overload is a dimensionless quantity, however, often overload is expressed in units of acceleration of gravity g. Overload in 1 unit (i.e. 1 g) is numerically equal to the weight of the body resting in the Earth’s gravity field. Overload at 0 g it is tested by a body in a state of free fall under the influence of only gravitational forces, that is, in a state of weightlessness.
Overload is a vector quantity. For a living organism, the direction of the overload is important. When overloaded, human organs tend to remain in the same state (uniform rectilinear movement or rest). With a positive overload (head - legs), the blood goes from head to foot, the stomach goes down. With negative overload, blood flow to the head increases. The most favorable position of the human body, in which he can perceive the greatest overloads - lying on his back, facing the direction of acceleration of movement, the most unfavorable for carrying overloads - in the longitudinal direction with his feet to the direction of acceleration. When a car collides with a fixed obstacle, a person sitting in a car will experience back-chest overload. This overload is tolerated without much difficulty. An ordinary person can withstand overloads of up to 15 g about 3 - 5 seconds without loss of consciousness. Overloads from 20 - 30 g and more a person can withstand without loss of consciousness no more than 1 - 2 seconds and depending on the magnitude of the overload.
Symptoms and mechanism of action of overloads
Common symptomsA person’s response to overloads is determined by their magnitude, rise gradient, duration of action, direction with respect to the main vessels of the body, as well as the "initial functional condition organism. Depending on the nature, magnitude and combinations of these factors, changes in barely perceptible functional shifts to extremely severe conditions may occur, accompanied by a complete loss of vision and consciousness in the presence of deep disorders of the cardiovascular, respiratory, nervous and second systems of the body.
General changes in the state of a person under the action of overloads are manifested by a feeling of heaviness throughout the body, at first difficulty, and with an increase in the magnitude of overload and a complete absence of movements, especially in the limbs, in some cases pain in the muscles of the back and neck [Babushkin V. P., 1959; de Graef P., 1983]. There is a clear displacement of the soft tissues and their deformation. During prolonged exposure sufficiently large positive overloads on areas of the legs, buttocks, and scrotum that are unprotected by back pressure, skin petechial hemorrhages may appear in the form of dots or large spots, intensely stained, but painless, which spontaneously disappear within a few days. Sometimes there is swelling in these places, and with negative overloads - swelling of the face. Early sight disorder. With large values \u200b\u200bof overloads, a loss of consciousness develops, which lasts 9-21 s.
The mechanism of action of positive and negative overloads is complex and is due to the primary effects caused by inertial forces. The most important of them are the following: redistribution of blood in the body to the lower (+ G Z) or upper (-G z) half of the body, displacement of organs and deformation of tissues, which are sources of unusual impulses in the central nervous system, circulatory, respiratory and stress reactions. Developing hypoxemia and hypoxia entail dysfunction of the central nervous system, heart, and endocrine glands. The biochemism of life processes is disrupted. Damage to cellular structures of a reversible or irreversible nature, detected by cytochemical and histological methods, may occur.
One of the basic requirements for military pilots and astronauts is the body's ability to endure overloads. Trained pilots in overload suits can carry overloads from −3 ... −2 g up to +12 g . Resistance to negative upward overloads is significantly lower. Usually at 7 - 8 g "blushes" in the eyes, vision disappears, and a person gradually loses consciousness due to a rush of blood to his head. Astronauts during take-off carry overload lying. In this position, the overload acts in the direction of the chest - back, which allows you to withstand several minutes overload of several units g. There are special anti-overload suits whose task is to facilitate the effect of overload. The costumes are a corset with hoses inflating from the air system and holding the outer surface of the human body, slightly preventing the outflow of blood.
Overloading increases the load on the design of machines and can lead to their breakdown or destruction, as well as to the movement of unsecured or poorly secured cargo. The permissible overload for civilian aircraft is 2.5 g
Pinosol spray: instruction
Analgin tablets: instructions, reviews, analogues Terms and conditions of storage of Analgin
Ginipral - description of the drug, instructions for use, reviews
Topical solution tantum verde
Chophytol and side effects