The influence of aerospace flights on the human body. Into orbit for longevity: how space flight affects the human body The influence of space flight on the human body

During a space flight, a person is influenced, in addition to the complex of environmental factors in which the flight of the space object takes place (static flight factors), also by factors determined by the flight dynamics. These primarily include accelerations and the resulting overloads, vibrations, weightlessness, and noise, which affect both the structure of the ship and its inhabitants.

Depending on the duration and purpose of the space flight, the influence of certain dynamic factors manifests itself to varying degrees. When studying their influence on the astronaut, special attention is paid to increasing the body's resistance to extreme influences, as well as to developing safety measures to reduce the adverse effects of these factors on the astronaut.

Acceleration

In aviation and space medicine, due to the specificity of the body's reactions, accelerations are divided into impact, i.e., short-term, and long-term.

Along with the term "acceleration" the term "overload" is used here. Overload shows how many times the resultant of external forces exceeds the weight of the body. The direction of acceleration is indicated in the coordinates of the human body, for example, head - pelvis (from head to pelvis), chest - back, etc.

Impact acceleration is characterized by a short duration (less than 1 second) and a high rate of increase in overload (from several hundred to several thousand g/sec). In space flight, shock acceleration occurs during ejection, during emergency separation (shooting) of the capsule with an astronaut from the launch vehicle, and, finally, during landing of the spacecraft. The figure shows a setup for studying shock overloads.

The body's resistance to shock application of mechanical forces is determined primarily by the strength of organs and tissues. Disturbances in body functions during impact acceleration may also occur at the microstructure level and may not have a clear localization in the general clinical picture. Immediately before the impact of accelerations, a number of emotionally conditioned reactions are observed - an increase in heart rate and respiratory rate, an increase in blood pressure, etc. In some cases, immediately after the impact, a pronounced inhibitory reaction can be observed (a slowdown in heart rate, a drop in blood pressure, a decrease in motor activity, etc. .). In the absence of traumatic injuries, normalization of functions occurs quite quickly.

Long-term accelerations in space flight occur during the ascent and descent of a spacecraft, and can also sometimes occur during maneuvers of the spacecraft during flight. In laboratory conditions, for the purpose of training and to study the effect of long-term accelerations on the human and animal body, special centrifuges are used.

Long-term acceleration is subjectively assessed as an increase in body weight with severe difficulty in breathing and limb movements. A feeling of fatigue gradually develops. Sometimes pain may occur in the retrosternal and epigastric regions. If long-term acceleration is directed along the axis of the leg - head or head - legs, then a rush of blood to the face and pain in the extremities is felt, intensifying towards the hands and feet. This phenomenon is due to the fact that, under the influence of inertial forces, a sharp redistribution of blood occurs in the vessels of the extremities. If long-term acceleration is directed along the back-chest or chest-back axis, the use of a seat with an individually modeled support protects the pilot from these phenomena associated with blood redistribution. If the opposite direction of long-term acceleration is envisaged, then more attention should be paid to the rational choice of the harness system on which the astronaut actually hangs. In this case, fixation of the head and limbs becomes of great importance.

Accelerations change the functional state of the central nervous system, which may be associated not only with impaired blood supply and increased nervous impulses, but also with the direct effect of inertial forces on brain tissue. The function of vision changes with the transverse direction of acceleration to a lesser extent than with its longitudinal direction. The auditory analyzer also suffers less. Its function of differentiated reception of information is practically preserved until consciousness is lost.

Quite often in the practice of aviation medicine, visual disturbances are used as a criterion for assessing a person’s tolerance to long-term accelerations. This is due to the fact that visual impairment in the form of a narrowing of the field of view, the appearance of a “gray” and then a “black” veil with longitudinally directed (legs - head) long-acting acceleration or a “red” veil (with the direction head - legs) are harbingers loss of consciousness as a consequence of a decrease in the level of cerebral circulation. The situation is different with transverse long-acting accelerations. Although in this case visual disturbances also indicate a disturbance in the blood supply to the retina, they are caused primarily by a disturbance of regional blood circulation in the vessels of the eye due to inertial forces acting in the forehead-back of the head direction, and in fact are not harbingers of a decrease in the overall level of cerebral circulation.

Changes in the functional state of the central nervous system and analytical systems, as well as difficulty in limb movements during acceleration lead to a decrease in human performance. The state of vegetative functions also changes significantly. The cardiovascular system responds by increasing heart rate and blood pressure (at heart level). The hemodynamics of the systemic and pulmonary circulation are disrupted. At high acceleration values (10 g and above), despite the body's increased need for oxygen, ventilation of the lungs decreases due to a decrease in the depth of breathing. At 20-22 g, the tidal volume approaches the volume of the “dead space”, when the inhaled air actually does not enter the lungs, but only the upper respiratory tract. X-ray data indicate that changes in the configuration and level of the diaphragm play a significant role in changes in the function of external respiration. Gas exchange in the body, including in the lungs, undergoes profound changes. Endocrine-humoral changes are noted, as well as morphological disturbances in organs and tissues, the degree of which depends on the strength, duration, direction and repetition of acceleration. The tension of muscle tissue changes.

When studying the effect of long-term transverse accelerations (equal to 7, 9, 10 g) on the human body, a significant increase in the frequency of respiratory movements was revealed, as well as a sharp decrease in the tidal volume of the lungs and, consequently, pulmonary ventilation.

In some individuals, pronounced disturbances in the function of cardiac excitability were observed, which manifested themselves in the form of single ventricular extrasystoles. At the same time, there was a noticeable decrease in blood pressure in the vessels of the auricle. Due to a drop in blood pressure and a decrease in the body's oxygen consumption, hypoxia of the central nervous system occurred with the subsequent appearance of visual disorders.

With transverse accelerations of the order of 10 g, a sharp disruption of the function of external respiration occurs, consisting of a delay in the respiratory act during the inhalation phase, and extreme overstrain of the cardiovascular system.

Long-term exposure of subjects with normal vestibular sensitivity to rotation causes functional changes. When exposed to angular accelerations equal to 30, 40, 60, 120 degrees/sec 2 , the subjects experienced illusory sensations and imbalance of the body, and in persons with increased vestibular sensitivity, changes in the position of the head at the moment of rotation or after one or two impacts of angular acceleration caused vestibulo-vegetative reactions: general weakness, pallor, sweating and nausea.

A lateral acceleration of 8 g for 3 minutes caused a 25% drop in blood oxygen saturation in humans. It was found that the action of transverse accelerations leads to a change in the level of oxygen saturation of brain tissue. In this case, a change occurs in the bioelectrical activity of the brain depending on the magnitude and duration of the acceleration.

An effective way to increase acceleration tolerance is to immerse a person in liquid. The protective mechanism of this method is to maximize the distribution of overload over the entire surface of the body. However, the application of this method poses significant difficulties from a technical point of view.

Vibration

Vibrations that occur during the operation of spacecraft engines are also a factor of mechanical impact on the body.

Vibrations are mechanical vibrations that occur at a frequency of one per second and higher. In practice, vibration is complex oscillatory movements, most often having simultaneously different directions and parameters. The simplest form of vibration is harmonic oscillations, when a body deviates along a sinusoid from some stable equilibrium position. As is known, periodic oscillatory movements are characterized by frequency, amplitude and so-called vibration acceleration. Vibration acceleration, or vibration overload, is the maximum change in speed per unit time (usually expressed in cm/sec 2).

The operation of the engine and the aerodynamic load of the ship create vibration in space flight. The frequency of vibration occurring during the active flight phase reaches approximately 50 Hz. The magnitude of vibration overload does not exceed 1 g. When exposed to a person, vibration causes specific sensations of body shaking.

It is customary to divide vibrations into low-frequency (less than 50 Hz) and high-frequency. The degree of impact of vibration depends on its parameters and duration, primarily on the vibration frequency. The body responds to vibrations of different frequencies with reactions that differ in both severity and character. For example, low-frequency vibrations, with limited distribution throughout the human body, cause dilation of blood vessels, and high-frequency vibrations cause their spasms.

Low-frequency vibrations are a specific irritant of the vestibular apparatus, which, with prolonged exposure, leads to disruption of its functions.

Under the influence of vibrations, the functions of breathing, the cardiovascular system, digestion, the musculoskeletal system, etc. undergo changes. There is no organ or system in the human body that, to one degree or another, does not respond to vibration effects. Vibration causes regular changes in the use of oxygen by brain tissue. Oxygen consumption during vibration, starting from the first exposure, increases sharply, most clearly in the motor area of the cerebral cortex. After vibration, during the first two hours, a wave-like development of the inhibitory process occurs, characterized by a decrease in oxygen consumption by brain tissue.

Prolonged exposure to vibration causes joint pain, nausea, headaches, general fatigue, and a noticeable decrease in performance.

However, since vibrations act for a short time, only during the active phase of the flight (when the engines are running), their noticeable effect on the astronauts’ body was not detected.

Weightlessness

Weightlessness is a state in which the force of gravity is absent or balanced by inertial forces. This is the most specific factor of space flight.

Weightlessness sets in on a spacecraft immediately after turning off the rocket engines, during the transition to orbital flight.

The absence of the influence of gravity greatly complicates the work of a person on board a satellite spacecraft and leads to loss of performance. In this case, a decrease in muscle tone occurs and the coordination of muscle movements is disrupted. The effect of weightlessness on the cardiovascular system is expressed in a slight decrease in blood pressure and heart rate with a periodic increase in heart rate. Functions such as breathing, swallowing food, defecation and urination are not affected.

Scientific research on spacecraft has made it possible to identify some physiological mechanisms of the effect of weightlessness on the human body. It was found that orthostatic disturbances in humans occur during descent from orbit, as well as immediately after landing of the spacecraft. During the same period, signs of weakening muscle tone are revealed, and cardiac arrhythmia is noted. However, it would be reckless at the present time to explain the nature of these reactions in astronauts only by their previous stay in a state of weightlessness. More thorough research is needed here, since influencing factors also include such factors as prolonged stay in conditions of reduced muscle activity, isolation, etc.

So far, no changes in mental functions have been observed under the influence of weightlessness. It is noted, however, that a person may develop spatial illusions in conditions of weightlessness.

The study of weightlessness in laboratory conditions is complicated by the fact that it cannot be created artificially. Complete weightlessness in the Earth's atmosphere lasting 1-2 seconds can be experienced in free fall, when air resistance does not affect it due to the initially low speed of the falling body. Weightlessness lasting 30-40 seconds occurs during flights on laboratory aircraft flying along parabolic trajectories.

Some semblance of static weightlessness is created if a person is placed in a pool of liquid whose density is equal to the average density of his body. In this case, gravitational forces are balanced by the surface pressure of the liquid, which creates a buoyant force according to Archimedes' law. It should be emphasized that the gravitational receptors of the internal organs are not turned off and, thus, a complete simulation of weightlessness is not achieved.

The state of weightlessness places special demands on the design and equipment of a spacecraft. Thus, every astronaut must be able to fix his body in the right place so as not to “float” during work. All items must be secured in their designated places. Since the behavior of liquids under weightlessness is determined by surface tension forces, water and other liquids require elastic vessels and sealed containers to prevent splashing. Due to the absence of convection mixing of air in zero gravity, its circulation inside the cabin must be provided by fans.

The exit of a person from a ship into outer space brings to the fore a new problem - the biomechanics of controlling body position and movement in unsupported space.

Soviet scientists made a great contribution to the study of weightlessness. Animal launches on geophysical rockets (since 1949) have proven the ability of living organisms to tolerate short-term weightlessness. The flight of the dog Laika on the second artificial satellite of the Earth proved the tolerance of long-term weightlessness.

The flight of Yu. A. Gagarin showed that weightlessness is not dangerous for the human body. Following this, G.S. Titov spent a day in a state of weightlessness. Subsequent flights of Soviet and American cosmonauts confirmed that a person, when staying in conditions of weightlessness for several months (up to 86 days), maintains health and good performance. Important scientific data were obtained during the 18-day flight of A. G. Nikolaev and V. I. Sevastyanov on the Soyuz-9 spacecraft. It turned out that in a state of weightlessness with good organization of work and rest, a person can not only live normally, but also effectively perform complex highly coordinated labor operations and maintain good performance for a long time. Research results have shown that after a long stay in a state of weightlessness, adaptation to terrestrial conditions is achieved by a more significant tension in regulatory systems than adaptation to a state of weightlessness.

The question of the influence of long-term weightlessness on a person acquires not only theoretical, but also purely practical significance. The most important task of modern science is to find active ways to prevent the harmful effects of weightlessness on the astronaut’s body and increase his performance.

Federal State Educational Institution of Higher Professional Education "Kurgan Agricultural Academy named after T.S. Maltsev"

Influence aerospace flights on organism person

Completed by student: 2 years, 2 groups, departments (PB) Ksenia Averina.

Checked by the teacher:

I. A. Geniatulina Kurgan 2012

1. Air travel

1.1 The impact of air travel on human health

1.2 Diseases that require special caution during air travel

1.3 Factors that affect the human body during air travel

2. Space flights

2.1 Immunity during space flight

2.2 The influence of weightlessness List of references

1. Air travel

Air travel today is the most convenient and fastest way to travel short and long distances anywhere in the world. Their purpose can be very diverse: travel, visiting relatives, business trips.

The plane, according to experts, is the safest form of transport. Hundreds and thousands of people are working on this.

The convenience of air travel lies largely in the fact that different companies offer the service of booking air tickets on-line (ordering) air tickets. The air ticket order form will help you obtain complete information about possible connections from the point of departure to the point of destination. You can choose one-way, round-trip or book a flight with multiple transfers. For business class passengers, choose a comfortable seat in the aircraft cabin.

1.1 Influence air travel on health person

With frequent and long air travel, the human body experiences significant overloads, which have a negative impact on it. So during a flight, as a result of temporary changes, a person’s biorhythms occur, which does not go unnoticed for certain parts of the human brain. The result of this negative impact is forgetfulness. Simply, due to frequent air travel, there is no adaptation period that the human body needs. Motion sickness is the most common result of the negative effects of overloads that a person experiences during a flight. The first sign of motion sickness is nausea, which occurs when changing flight altitude. At this moment, blood pressure rises, which is accompanied by congestion in the ears, headache, and weakness. The most sensitive to this type of short-term overload are people suffering from hypertension and pregnant women. Diuretics and lozenges will help get rid of these unpleasant sensations. You should also not overeat before a flight. If signs of illness such as rapid breathing or a feeling of lack of oxygen appear, then taking deep breaths through the mouth will help.

Even moderate-duration air travel, which lasts only about 4 hours, can cause vascular thrombosis. Blood clots begin to form in the vessels in the first 2-3 hours of the flight. Their number grows along with the increase in the duration of the flight itself. Especially at risk of thrombosis are pregnant women, women taking hormonal medications, and passengers who have recently undergone surgery. To avoid the risk of thrombosis, you must follow simple rules. The first thing to do is to drink constantly and slowly, in small sips of non-carbonated water. Thus, water is better absorbed by the body and will remain in it for a longer time. Movement improves blood flow in the human body. This may not be a long walk around the aircraft cabin, waving your arms, etc.

1.2 Diseases, at which need to observe special caution in time air travel

- incoagulability or increased blood clotting;

- hypertension, coronary heart disease and some other cardiovascular diseases;

- diseases of the respiratory system: chronic bronchitis, emphysema, bronchiolitis obliterans;

- diabetes;

— other chronic diseases of vital organs and systems.

In all these cases, before flying, you should consult your doctor to discuss the possible risks and take the necessary measures.

The topic of air travel during pregnancy causes quite a lot of controversy. All doctors and airlines agree on one thing. You cannot travel by air after 36 weeks of pregnancy and within a week after giving birth. You should also not go on an air trip with children who are not yet a month old.

Even if you are healthy, air travel can give you a certain dose of discomfort. What is this connected with? With special conditions that are not so often observed in familiar and familiar ground situations.

1.3 Factors which act on human organism at air travel

air travel space weightlessness health Any air travel is always a limitation of mobility. The longer we stay in a sitting position, the greater the load on the lower body. Blood circulation in the legs slows down, blood vessels narrow, legs swell and hurt. The risk of venous thrombosis—blockage of veins due to the formation of blood clots—is increasing. Pressure differences in the aircraft cabin also play a significant role.

1) Forced inactivity

How to prevent blood stagnation in the veins of the lower extremities? The easiest way is to move around at least a little. It is advisable to get up from your seat every half hour or hour and walk back and forth around the cabin. You can take an aisle seat so you can stand up more often, stretch your legs, bend and straighten them. It is useful to do a couple of basic physical exercises. But you shouldn’t sit in a chair with your legs crossed. This causes the vessels to be compressed even more. It is also undesirable to keep your legs bent at an acute angle for a long time. It is better if the angle at the knee is 90 degrees or more.

2) Overload at takeoff And landing

Overloads during takeoff and landing give passengers a lot of unpleasant sensations. The body reacts to them in a very specific way - tension, and sometimes pain in the muscles. In addition, pressure drops are inevitable when ascending and descending. This causes pain in the ears. To equalize the pressure in the ears, you need to “blow” - make movements similar to yawning. At the same time, an additional volume of air from the nasopharynx enters the ears through the Eustachian tubes. However, if the nose is “stuffed,” “blowing” during takeoff and descent becomes more difficult, and the discomfort in the ears becomes much greater. In addition, microbes can enter the ear along with air from the nasopharynx, and then it is not far from otitis media - inflammation of the middle ear. For this reason, it is not recommended to fly with diseases such as acute respiratory infections, sinusitis or sinusitis.

3) Other atmospheric pressure

The pressure in the aircraft cabin is approximately equal to the pressure at an altitude of 1500 - 2500 meters above sea level. This is a major risk factor for cardiovascular patients. At lower atmospheric pressure, the oxygen tension (Pa O2) in the cabin air drops. Critical values are observed already at an altitude of more than 3000 meters, and during long flights the plane can gain altitude up to 11,000 m. Accordingly, the supply of oxygen to the blood decreases, and this is very dangerous. Some patients in such a situation require oxygen inhalation, but this is extremely difficult to do on board. Most airlines do not allow oxygen bags on board because the gas is explosive. The most acceptable way out of this situation is to order an oxygen inhalation service two, or better yet, three days before the flight. This should be done by a doctor.

4) Low humidity air V salon airplane

Eye diseases can cause complications due to low air humidity on the plane. Its level is usually about 20%, and sometimes less, while the comfortable value for a person is 30%. At lower humidity, the mucous membranes of the eyes and nose begin to dry out, which is what we fully experience during air travel. This causes a lot of unpleasant moments, especially for those who wear contact lenses. Ophthalmologists recommend taking “artificial tear” drops on a flight to periodically irrigate the mucous membrane. This is especially important on flights lasting more than 4 hours. An alternative option is to go on a flight not with lenses, but with glasses. You should not remove lenses directly on the plane, since the environment in any transport is not hygienic enough. Doctors advise the fair sex to use minimal cosmetics during long flights, as the sensitivity of the eyes increases, and mascara or eye shadow can cause irritation.

To replenish the lack of moisture, it is recommended to drink more juices or plain still water during the flight. But tea, coffee and alcohol do not restore the body’s water balance. On the contrary, they remove moisture from the body.

2. Space flying

When flying into outer space, living organisms encounter a number of conditions and factors that are sharply different in their properties from the conditions and factors of the Earth's biosphere. Space flight factors that can influence living organisms are divided into three groups.

The first includes factors associated with the flight dynamics of a spacecraft: overloads, vibrations, noise, weightlessness. Studying their effect on living organisms is an important task of space biology.

The second group includes factors of outer space. Outer space is characterized by many features and properties that are incompatible with the requirements of terrestrial organisms for environmental conditions. This is, first of all, the almost complete absence of gases that make up the atmosphere, including molecular oxygen, high intensity of ultraviolet and infrared radiation, the blinding brightness of visible light from the Sun, destructive doses of ionizing (penetrating) radiation (cosmic rays and gamma rays, X-rays and etc.), the uniqueness of the thermal regime in space, etc. Space biology studies the influence of all these factors, their complex impact on living organisms and methods of protection against them (https://site, 25).

The third group includes factors associated with the isolation of organisms in the artificial conditions of a spacecraft. Flight into outer space is inevitably associated with more or less long-term isolation of organisms in relatively small pressurized cabins of spacecraft. Limited space and freedom of movement, monotony and monotony of the situation, the absence of many stimuli familiar to life on Earth create completely special conditions. Therefore, special studies of the physiology of higher nervous activity, the resistance of highly organized beings, including humans, to long-term isolation, and the preservation of working capacity under these conditions are necessary.

2.1 Immunity at space flight

After long flights, astronauts experience a decrease in the overall immunological reactivity of the body, which is manifested by: - a decrease in the blood content and reactivity of T-lymphocytes;

— decrease in the functional activity of T-helpers and natural killer cells; - weakening of the synthesis of the most important bioregulators: IL-2, a- and p-interferon, etc.; - increased microbial contamination of the skin and mucous membranes; - development of dysbacterial changes; - increasing the resistance of a number of microorganisms to antibiotics, the appearance and intensification of signs of their pathogenicity.

The significance of the identified changes in immunological reactivity and the automicroflora of an astronaut’s body both during and after space flight is that these changes can increase the likelihood of developing autoimmune diseases, as well as diseases of a bacterial, viral and allergic nature. All this must be taken into account when planning and medical support for long-term space flights.

2.2 Influence weightlessness

The state of weightlessness occurs when no external forces are applied to a body located in space, except for the force of gravity. If a spacecraft is in a central gravitational field and does not rotate around its center of mass, it experiences weightlessness, a characteristic feature of which is that the accelerations of all structural elements, instrument parts and particles of the human body are equal to the acceleration of gravity.

A positive property of weightlessness is the possibility of using openwork, thin and very light structures (including inflatable ones) in space when creating large-scale structures in orbit (for example, giant radio telescope antennas, solar panels of orbital power plants, etc.).

Flight in zero gravity requires securing equipment and equipment in place, as well as equipping the manned spacecraft with means of securing the astronauts, their labor and household items.

The primary effects of weightlessness are the removal of hydrostatic pressure of blood and tissue fluid, the weight load on the musculoskeletal system, as well as the absence of gravitational stimuli of specific gravireceptors of the afferent systems. The body's reactions, caused by a long stay in weightlessness, essentially express its adaptation to new environmental conditions and proceed according to the type of “disuse” or “atrophy from inactivity.”

The state of weightlessness in the initial period often causes disturbances in spatial orientation, illusory sensations and symptoms of motion sickness (dizziness, stomach discomfort, nausea and vomiting), which is associated mainly with reactions of the vestibular apparatus and a rush of blood to the head. There are also changes in the subjective perception of loads and some other changes caused by the reactions of sensitive organs that are tuned to earthly gravity. During the first ten days of being in weightlessness, depending on the individual sensitivity of a person, as a rule, adaptation to the indicated manifestations of weightlessness occurs and well-being is restored.

In conditions of weightlessness, a restructuring of movement coordination occurs, and detraining of the cardiovascular system develops.

Weightlessness affects fluid balance in the body, the metabolism of proteins, fats, carbohydrates, mineral metabolism, as well as some endocrine functions. There are losses of water, electrolytes (in particular, potassium, sodium), chlorides and other changes in metabolism.

The weakening of external forces on weight-bearing structures leads to loss of calcium and other substances important for maintaining bone strength. After prolonged exposure to weightlessness, mild muscle atrophy, some weakness of the muscles of the limbs, etc. are possible.

Among the most common manifestations of the adverse effects of weightlessness on the body in combination with other features of living conditions on a spacecraft is asthenia, some signs of which (deterioration in performance, rapid fatigue) are detected already during the flight itself. However, the most noticeable effect of asthenia is upon returning to Earth. A decrease in body weight, muscle mass, bone mineral saturation, a decrease in strength, endurance, and physical performance limit the tolerance of stress typical for this period of overload and the effects of earthly gravity.

Changes in immunological reactions and resistance to infections are accompanied by an increase in susceptibility to diseases, which can lead to a critical situation during flight. During short-term flights, no significant changes in immunological reactivity were noted.

There is a certain probability that some other changes in the functional state of the body can affect the duration of a safe stay in conditions of prolonged weightlessness. Some of them are determined by the processes of restructuring the mechanisms of nervous and hormonal regulation of autonomic and motor functions, others depend on the degree of structural changes (for example, muscle and bone tissue), detraining of the cardiovascular system and metabolic shifts. The development and implementation of a system of measures to prevent these disorders is one of the important tasks of medical support for long-term space flights.

In principle, there are two possible ways to prevent the effects of weightlessness. The first is to prevent the body from adapting to weightlessness by creating on the spacecraft an artificial gravity force equivalent to that on Earth; this is the most radical.!, but a complex and expensive method, which excludes precision observations of external space and the possibility of experiments in conditions of weightlessness. The second method allows for partial adaptation of the body to weightlessness, but at the same time provides for the adoption of measures to prevent or reduce the adverse consequences of adaptation. The preventive effect of protective equipment is designed primarily to maintain a sufficient level of physical performance, motor coordination and orthoetatic stability (overload tolerance and vertical posture), since, according to modern data, changes in these functions that occur during the readaptation period seem to be the most critical.

Replenishing the deficit of weight load on the musculoskeletal system in conditions of weightlessness is one of the very promising areas in the development of preventive measures and is ensured through physical training using spring or rubber expanders, bicycle ergometers, treadmill-type exercise machines and load suits that create a static load on the body and individual muscle groups due to rubber rods.

In the system of preventing shifts, mainly due to the lack of weight load on the musculoskeletal system, other methods of influence can be used, in particular, electrical stimulation of muscles, the use of hormonal drugs that normalize protein and calcium metabolism, as well as various methods of increasing the body’s resistance to infections.

The general system of protective measures should also take into account the possibility of increasing the body's nonspecific resistance by reducing the adverse effects of space flight stress factors (reducing noise levels, optimizing temperature, creating proper hygienic and household amenities), ensuring sufficient water consumption, nutritious and well-balanced nutrition with increased vitamin saturation, providing conditions for rest, sleep, etc. Increasing the internal volume of spacecraft and creating improved household amenities on them significantly help mitigate adverse reactions to weightlessness.

It should be noted that in the system of measures to prevent the adverse effects of prolonged weightlessness on the human body, independent importance belongs to pre-flight selection and training, as well as rehabilitation therapy used in the post-flight period.

List used literature

1. "Spacecraft" \Under the general editorship of prof. K. P. Feoktistova - Moscow: Military Publishing House, 1983 - p.319

2. http://www.d-nikolaev.ru/publ/7−1-0−52

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The influence of long-term space flight on the human body - page No. 1/1

INFLUENCE OF LONG-TERM SPACE FLIGHTON THE HUMAN BODY

(Some results of biomedical researchin connection with the flight of the Soyuz-9 spacecraft)

Corresponding Member of the USSR Academy of Sciences

O. G. GAZENKO,

Candidate of Medical Sciences

B. S. ALYAKRINSKY

In practice, space exploration at the present time means, first of all, an extension of both orbital and interplanetary flights, and, consequently, an inevitable increase in the length of time a person spends in unusual conditions of existence. It is quite obvious that the duration of these periods will directly determine the result of the impact on the human body of all factors of space flight, and above all the most significant ones - such as weightlessness, increased levels of radiation, afferentation changed in composition and quantity, which is in many ways different from the “earthly” one. a system of time sensors (stimuli that regulate the circadian rhythms of all body functions). However, very little is known about the specific features of this dependence. Science has extremely scanty data in this regard. Meanwhile, the question of how long a person can stay in space without damage to health and performance is one of the most pressing in modern astronautics. That is why the flight of the Soviet spacecraft Soyuz-9 with two cosmonauts on board, who were in space for 18 days, is attracting so much attention, i.e. 4 days more than the American cosmonauts F. Borman and D. Lovell, the previous holders of the world record for orbital flight duration.

Already during the planning and practical preparation of the Soyuz-9 flight, it was possible to obtain, as a result of medical and biological observations and research, data different from those that were delivered by previous flights of both Soviet and American cosmonauts. Reality did not disappoint these expectations, which was largely facilitated by the greater completeness and systematicity of the medical examination of the cosmonauts before, during and after the flight, and most importantly, by the length of stay of A.G. Nikolaev and V.I. Sevastyanov in orbit.

The flight of the Soyuz-9 spacecraft went exactly according to the program. The microclimate parameters in its living compartments fluctuated within the prescribed limits: total pressure - 732-890 mm rt. Art., partial pressure of oxygen - 157-285, carbon dioxide 1.3-10.7 mm rt. Art., relative humidity - 50-75%, air temperature - from 17 to 28 ° C. The astronauts ate canned food from natural products 4 times a day, the calorie content of the daily diet was on average 2700 kcal The drinking regime provided for the consumption of about 2 liters of liquid per day by each astronaut (including metabolic water). Twice during the day, the cosmonauts performed a set of physical exercises specially designed for the flight.

Due to the precession of the orbit and the need to land the spacecraft during daylight hours, the astronauts' sleep and wakefulness schedule differed significantly from usual. At the first stage of the flight they lie down

went to sleep at / o'clock. morning Moscow time, and then the beginning of sleep gradually moved to earlier hours, approaching midnight. Thus, on board the Soyuz-9 spacecraft, a variant of the so-called migrating days with an initial 9-hour phase shift was used.

During the flight, with the help of special on-board medical monitoring equipment, data from recording electrocardiograms, seismic cardiograms and pneumograms of the cosmonauts both at rest and during functional tests and work operations were systematically transmitted to Earth. As a form of mutual monitoring, the astronauts measured each other's blood pressure. Using the “Vertical” installation, the ability to spatial orientation was studied. According to a pre-compiled program, the astronauts reported on their well-being. Radio traffic and television surveillance data supplemented these reports.

The ship's flight took place in a favorable radiation environment.

Pre-launch period and flight period. As the launch time approached, both cosmonauts experienced an increase in heart rate and breathing, which was natural for such a situation. If on the eve of the start the maximum heart rate of A. G. Nikolaev was 90, and that of V. I. Sevastyanov was 84 beats/min, then during the period of hourly readiness it reached 114 and 96, respectively beats/min. A similar reaction was noted in relation to breathing: on the eve of the start, the maximum respiratory rate for A. G. Nikolaev was 15, for V. I. Sevastyanov - 18, and during the period of one-hour readiness it increased for both to 24 per minute.

During the active phase of the flight, the cosmonauts' pulse and breathing rates were at the level of the pre-launch period.

After the spacecraft entered orbit on the 6th orbit of the flight, the heart rate approached that recorded a month before the launch and accepted as background. Subsequently, the heart rate continued to fall. By the 3rd day of the flight, it decreased relative to the background for A. G. Nikolaev by 8-10, for V. I. Sevastyanov by 13 beats/min and remained at this level for about 10 days, after which it began to gradually increase and in the last third of the flight did not differ statistically significantly from the background indicators. When spinning the spacecraft, correcting its orbit, orientation, as well as when the astronauts performed physical exercises and conducted some experiments, a pronounced increase in heart rate was noted in both crew members. So, on the 33rd orbit, when flight engineer V.I. Sevastyanov, performing an experiment on celestial orientation, took control of the ship, his pulse rate increased to 110 beats/min.

The respiratory rate throughout the flight was not statistically significantly different from that recorded in background studies (A.D. Egorov et al.).

As the spacecraft entered orbit, both crew members experienced a sensation of blood rushing to the head, accompanied by the appearance of puffiness and redness of the facial skin. This sensation decreased significantly on the 2nd day of the flight, but subsequently intensified when attention was fixed on it. The acuity of the sensation noticeably decreased when the ship was spinning, when the cosmonauts were positioned along the vector of the centripetal force with their heads towards the center of rotation.

The cosmonauts' sensory-motor coordination was somewhat impaired during the 3-4 days of the flight, which was reflected in some disproportion and inaccuracy of movements. On the 4th day, the movements began to acquire their characteristic clarity.

42 O. G. GAZENKO, B. S. ALYAKRINSKY

The process of orientation in space was difficult during the entire period of weightlessness for both A. G. Nikolaev and V. I. Sevastyanov. This was expressed in the fact that when swimming freely with their eyes closed, they quickly lost the idea of the position of their body in relation to the coordinates of the cabin. Determining the vertical direction with open and closed eyes using the “Vertical” installation, the astronauts in each study made errors that were more significant than before the flight.

Analysis of daily urine collected on the 1st, 2nd and 18th days of the flight showed an increase in the excretion of potassium, calcium, sulfur, phosphorus and nitrogen. The amount of oxycorticosteroids in the first two portions of urine was reduced, in the third it approached the background level (G.I. Kozyrevskaya et al.).

Data from radio communications, messages transmitted from the ship, and television surveillance indicate that throughout the flight the behavior of the astronauts was fully consistent with their individual psychological characteristics and specific situations.

Starting from the 12th-13th day of the flight, fatigue appeared after performing complex experiments and a busy day of work.

According to the astronauts, their appetite during the flight was normal, the feeling of thirst was somewhat reduced, and their sleep was generally deep, refreshing, lasting 7-9 hours.

Post-flight period. During the initial medical examination after the flight, the astronauts looked tired, their faces were puffy, and their skin was pale. Maintaining an upright posture required a certain amount of effort, so they preferred a lying position. The leading sensation they had at this time was an apparent increase in the weight of the head and the whole body. This sensation was approximately equal in intensity to that which occurs with an overload of 2.0-2.5 units. The objects they had to manipulate seemed extremely heavy. This peculiar illusion of weight gain, gradually weakening, persisted for about 3 days.

The cosmonauts endured a shortened (5-minute) orthostatic test performed at this time with pronounced tension.

The weight of A. G. Nikolaev was reduced by 2.7 kg, and that of V. I. Sevastyanov - by 4.0 kg.

On the 2nd day after the flight, during a stabilographic examination, a significant increase in the amplitude of oscillations of the general center of gravity of the body was noted in both cosmonauts. The muscle tone of the lower extremities was reduced, the knee reflex sharply increased. A. G. Nikolaev’s deadlift strength decreased by 40 kg, for V.I. Sevastyanov - at 65 kg. The perimeters of the lower leg and thigh in both of them decreased.

The restoration of orthostatic stability lasted about 10 days of the post-flight period.

Determination, using X-ray photometric and ultrasound methods, of the density of some areas of the astronauts’ skeleton showed that it decreased, especially significantly in the lower extremities. This decrease on the 2nd day after the flight reached 8.5 - 9.6% in the calcaneal bones, and only 4.26-5.56% in the main phalanges of the fingers (E. N. Biryukov, I. G. Krasnykh ).

On the 22nd day of the post-flight period, the optical density of bones had not yet reached the initial level.

When studying the automicroflora of the skin and nasal mucosa, pronounced dysbacteriosis was noted. Dysbacteriotic changes

INFLUENCE OF SPACE FLIGHT ON THE BODY

mainly came down to the appearance on the smooth skin and nasal mucosa of astronauts of a large number of gram-positive non-spore-bearing rods, which were not detected before the flight, which, apparently, gives grounds to classify them as representatives of the “adventive flora” (V.N. Zaloguev).

Medical observation materials obtained during the flight of the Soyuz-9 spacecraft and in the post-flight period indicate the fundamental possibility of human existence in space for 18 days while maintaining sufficient mental and physical performance. At the same time, this material leads to the conclusion that, in general, the “adaptation-readaptation” cycle in space-Earth conditions requires prolonged strain on the body’s adaptive mechanisms and that readaptation to familiar living conditions is a more difficult process.

The development of tools and methods to facilitate this process is an important task in space medicine. To solve it successfully, it is necessary to sufficiently determine the specific importance of each factor of space flight in the influence that their complex has on the human body. Of no less importance is the study of the mechanisms of the body's response to each of these factors. Progress in this direction can only be ensured by accumulating a large amount of factual material.

The significance of the 18-day flight of Soviet cosmonauts from this point of view can hardly be exaggerated. It is undoubtedly a major step in resolving the issue of the differential significance of space flight conditions, the share of their participation in changes in physiological functions of astronauts in orbit and after returning to Earth.

What conditions on board Soyuz 9 were responsible for these changes?

Radiation can be immediately excluded from these conditions. In fact, the total radiation dose received by each astronaut was well below acceptable levels.

The role of neuro-emotional stress in the overall response of the astronauts to the flight also, apparently, was relatively small. In any case, the content of oxycorticosteroids in their urine turned out to be reduced in relation to the conventional norm, although it is known that any neuro-emotional stress is accompanied by an increase in the amount of these substances in the blood and urine. Thus, in individuals (non-pilots) who made a 50-minute flight in the airfield area, the level of steroid hormones increased by 40-50% compared to pre-flight levels (X. Hale, 1959). In professional pilots, after short-term, but very difficult flights on jet aircraft that they have mastered, the amount of 17-OH-corticosteroids in the urine during the first two to three hours after the flight increases by 50-60% (I.V. Fedorov, 1963).

These and many other data suggest that the neuro-emotional stress of the Soyuz-9 crew members was not significant, at least on the 1st, 2nd and 18th days. And since it was precisely on these days that the most intense emotional reaction in astronauts, natural at the start and finish, could be expected, emotiogenic factors cannot be considered a significant cause of the changes in physiological functions noted in them.

In all likelihood, the severity of the experiences of A. G. Nikolaev and V. I. Sevastyanov was reduced due to the successful, uncomplicated

O. G. GAZENKO, B. S. ALYAKRINSKY

the implementation of the flight program, favorable radiation conditions, uninterrupted radio and television communications during the hours of scheduled sessions, good preliminary training of both crew members, and also the fact that one of the cosmonauts had already flown and his confidence in the successful completion of the flight was transferred to his partner.

The significance of the disruption of the “afferent supply” of the cosmonauts’ body during the Soyuz-9 flight is quite difficult, if not impossible, to assess with sufficient completeness and reliability. However, some considerations in this regard are worthy of attention.

In experiments studying the so-called sensory insufficiency, carried out in terrestrial conditions, it was shown that the depletion of the general afferent flow does not pass without a trace for humans. Its first and main result is various disorders in the mental sphere, which are most pronounced in cases of the most complete exclusion of visual, auditory, tactile, kinesthetic and other sensations. In such experiments, subjects experienced various changes in consciousness, including hallucinations. The main difference between these experiments and the conditions of space flights is the impossibility of excluding on Earth afferentation coming from gravireceptors, while in space it weakens and, apparently, changes.

During the entire flight, neither A. G. Nikolaev nor V. I. Sevastyanov had a single case of mental disorders. Their behavior in the broadest sense of the word, the quality of work and research operations, their speech and the content of transmitted information, entries in the logbook, etc. indicate that the astronauts did not experience a state of sensory deprivation, at least in the form which is typical for ground-based experiments. The influence of the altered composition and quantity of afferentation (primarily proprioceptive and tactile, and also, to some extent, vestibular, visual and auditory) on the psyche of the astronauts was either very insignificant or well contained.

Thus, neither radiation, nor neuro-emotional stress, nor sensory impairment can be considered as significant causes of changes in physiological functions. There is every reason to consider weightlessness, as well as the unusual rhythm of sleep and wakefulness of the Soyuz-9 crew members, among the most important reasons for these shifts.

The problem of weightlessness continues to be an arena of heated debate between representatives of different points of view. While some researchers do not attach any serious importance to weightlessness (L. Mallon, 1956; I. Walrath, 1959), others believe that it is a formidable damaging factor and that the existence of terrestrial organisms in conditions of weightlessness is impossible. Moreover, there is an opinion that even a long-term change in the direction of gravity at a low weight can be fatal for the body (V. Ya. Brovar, 1960).

Based on the data of comparative physiology, even the following conclusion is formulated: the evolution of animals is essentially the evolution of adaptations aimed at overcoming the forces of gravity, which was associated with increased expenditure of energy, the release of which requires a significant amount of oxygen, and therefore hemoglobin. From this point of view, in weightlessness, the erythropoietic function will gradually decrease, as a result of which progressive bone marrow atrophy will begin (P. A. Korzhuev, 1968).

Numerous works by domestic and foreign authors emphasize the negative impact of weightlessness not only on bone function,

INFLUENCE OF SPACE FLIGHT ON THE BODY

of the brain, but actually on all systems of the body, on the body as a whole. “Vulnerability” in conditions of weightlessness of the cardiovascular and musculoskeletal systems is especially noted.

Experiments carried out in swimming pools and elevators, during the flight of specially equipped aircraft along a ballistic curve, data obtained in orbital flights, and theoretical developments make it possible with a high degree of probability to attribute the following phenomena to the effects of weightlessness on the human body: various disturbances of spatial orientation, some types of so-called vestibular illusions, in particular oculogyral, changes in the temporal-spatial-power structure of motor skills, hemodynamic changes (one of the symptoms of which is hyperemia and puffiness of the face associated with increased blood flow to the head), decreased physical strength and atrophic phenomena in the muscle tissue and skeletal decalcification.

When returning to the Earth's gravitational field, the aftereffect of weightlessness is expressed in increased lability of the cardiovascular system, one of the manifestations of which is orthostatic instability, in disruption of functional motor structures responsible for maintaining posture and locomotion, in the appearance of the illusion of an increase in the weight of one's own body and objects of familiar weight. .

When comparing this complex, multicomponent response of the body only to weightlessness with those reactions to flight as a whole that were recorded by A. G. Nikolaev and V. I. Sevastyanov, one cannot help but come to the conclusion that in space, apparently, the leading weightlessness is a factor.

However, there is reason to associate some of the reactions of cosmonauts noted in orbit not only with weightlessness, but also with the uniqueness of their work and rest regime. As already noted, the astronauts lived according to the scheme of the so-called migrating days with an initial phase shift of about 9 hours. Nowadays, very numerous data from special studies indicate that a person’s work and rest regime turns out to be closer to optimal, the closer the sleep and rest schedule in this regime coincides with the circadian rhythms of its psycho-physiological functions inherent in the human body. Numerous facts indicate that the well-being of the body is directly dependent on these rhythms. Thus, K. Pittendray (1964) points out that circadian rhythms are an integral property of living systems, form the basis of their organization, and that any deviation from the normal course of the rhythm leads to disturbances in the functioning of the entire organism. The normal course of the rhythm is supported by cyclically changing factors of the external world, which in biorhythmology are called synchronizers or time sensors. Most of them are the result of the Earth's rotation around its own axis. In all cases of mismatch between the cycles of time sensors and the rhythms of the body, the latter experiences a state of so-called desynchronosis, which in relation to a person takes the form of severe fatigue, overwork, or even various reactions of a neurotic type.

Desynchronosis can occur in all cases of disruption of the usual time sensor system: when quickly crossing several time zones (transmeridional flights), when working at night, in Arctic and Antarctic conditions, in space flights. One of the causes of desynchronosis is also the migration of the day, i.e. a constant or periodic change in the onset of sleep, and hence wakefulness, in the 24-hour period. mode of work and rest.

4$ O. G. GAZENKO, B. S. ALYAKRINSKY

The migrating days experienced on board the Soyuz-9 spacecraft may be one of the reasons for the fatigue of the cosmonauts, which they first noted on the 12th-13th day of the flight. There is reason to believe that the negative impact of weightlessness was enhanced by periodic changes in the rhythm of sleep and wakefulness (B. S. Alyakrinsky).

Ranking of extreme factors in relation to the flight conditions of the Soyuz-9 spacecraft can be useful for specifying preventive measures aimed at reducing the negative impact of these factors. Since the specific value of weightlessness seems to be greatest, the idea of artificial gravity (i.e., the use of the principle of centrifugation) receives an additional argument in its favor.

Muscular atrophy, which appeared in astronauts only in relation to the lower extremities, apparently can be successfully prevented by specially selected physical exercises.

It is absolutely clear that the most serious attention should be paid to maintaining the inherent daily rhythms of the body's functions during long-term space flights. The difficulties of adapting to unusual daily rhythms must be taken into account when setting up a system for selecting cosmonauts. It has been experimentally shown that people react differently to an emergency change in work and rest schedules. For some, this change is extremely easy; for others, on the contrary, it presents a difficult task. Reliable prevention of desynchronosis on board a spacecraft is strict adherence by astronauts to rational work and rest regimes, developed on the basis of biorhythmology data.

The study of the problem of long-term human existence in space is just beginning. This problem can be resolved only by accumulating more and more new facts in long-term space flights, with a specially developed program of medical observations. Such flights include the flight of the Soyuz-9 spacecraft.

2. Space flights

Immunity during space flight

After long flights, astronauts experience a decrease in the overall immunological reactivity of the body, which is manifested by: - a decrease in the blood content and reactivity of T-lymphocytes;

Decreased functional activity of T-helper cells and natural killer cells; - weakening of the synthesis of the most important bioregulators: IL-2, a- and p-interferon, etc.; - increased microbial contamination of the skin and mucous membranes; - development of dysbacterial changes; - increasing the resistance of a number of microorganisms to antibiotics, the appearance and intensification of signs of their pathogenicity.