Working increase physiology. BX. Equations for calculating the value of the main exchange. Body surface law. Energy costs of the body in conditions of physical activity. The coefficient of physical activity. Working increase
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The minimum amount of energy needed to sustain an organism called basal exchange. It makes up about 50-70% of the daily energy expenditure of a person leading a sedentary lifestyle.
Factors affecting basal metabolism
Three factors have the maximum influence (on average) on the value of the basic metabolism: age, sex and body weight.
Average muscle mass in men higher by 10-15%. Almost by the same value, women have more adipose tissue, which results in a lower basal metabolic rate.
This dependence also determines influence of human age on the value of the main exchange. The average statistical person loses more and more of his muscle mass with age - every year both physical and social activity decreases.
Body weight has a direct effect on the basal metabolic rate - the more weight of a person, the more energy is expended on any movement or movement (and it doesn’t matter what moves - muscle tissue or fat).
Proper basal metabolism can be estimated from the tables of Harris and Benedict, taking into account the sex, weight, height and age of the subject. There are formulas for the arithmetic calculation of due.
The true one differs from the due one, and often it is this difference that has a diagnostic or prognostic value. Therefore, the assessment of the proper does not replace the definition of the actual.
Working increase. General energy consumption of various professional groups.
Working increase it is energy expenditure for physical and mental work. According to the nature of production activities and energy consumption, the following groups of the population are distinguished:
1. Persons of mental labor (teachers, students, doctors, etc.). Their energy consumption is 2200-3300 kcal/day.
2. Workers engaged in mechanized labor (assemblers on the conveyor). 2350-3500 kcal/day
3. Persons engaged in partially mechanized labor (chauffeurs, turners, locksmiths). 2500-3700 kcal/day
4. Occupied with heavy non-mechanized labor (loaders). 2900-4200 kcal / day. The specific dynamic effect of food is the energy consumption for the absorption of nutrients. It is most pronounced in proteins. Less fat and carbohydrates. In particular, proteins increase energy metabolism by 30%, and fats and carbohydrates by 15%.
Metabolism and energy as a necessary condition for life. Stages of heat and energy generation. Direct and indirect calorimetry. Caloric coefficient of oxygen. respiratory rate.
Metabolism and energy, or metabolism- a set of chemical and physical transformations of substances and energy that occur in a living organism and ensure its vital activity.
Anabolism- is the process of assimilation of substances by the body, in which energy is consumed.
catabolism- the process of decomposition of complex organic compounds, proceeding with the release of energy.
Direct calorimetry- calculation of energy costs consists in direct measurement of the amount of heat directly released by the body in the heat-insulating chamber.
Indirect calorimetry - change in the amount of oxygen consumed and carbon gas released, as well as the calculation of the respiratory coefficient and the calculation of the caloric equivalent of oxygen.
Caloric coefficient of oxygen- the amount of heat generated in the body as a result of the consumption of 1 liter of oxygen.
Respiratory coefficient- the ratio of the volume of allocated carbon dioxide to the amount of oxygen.
74.Principles of compiling a diet. Nutrition theories. Nutrition should meet the body's needs for plastic substances and energy, mineral salts, vitamins and water, ensure normal life, good health, high performance, resistance to infections, growth and development of the body. a number of principles must be followed:
The calorie content of the diet should correspond to the energy costs of the body for all types of life.
Nutritional value to be considered nutrients. The diet should contain the optimal amount of proteins, fats and carbohydrates for a given individual or professional group, minerals, vitamins and water.
It is required to maintain a balance in the diet of the amount of proteins, fats, carbohydrates and minerals.
It is important to correctly distribute the calorie content of the diet for individual meals during the day in accordance with biorhythms, the regimen and nature of labor and other activities.
Application of technological processing methods that ensure the removal harmful substances that do not cause a decrease in the biological value of food, and also do not allow the formation of toxic products.
Ensuring the organoleptic qualities of food, contributing to its digestion and assimilation.-
The presence in the diet of dietary fiber, which contributes to the removal of toxic decay products from the body.
Nutrition Theory:
The theory of balanced nutrition - that a good nutrition is characterized by the optimal correspondence of the quantity and ratio of all food components to the physiological needs of the body. This means that all the food eaten per day should go to replenish physical costs.
The theory of direct nutrition is suitable only in exceptional cases, mainly in the treatment of seriously ill patients. (Nutrition through a tube)
The theory of adequate nutrition - the necessary components of food are ballast substances; intake of biological substances into the body; in the process of assimilation and exchange important intestinal microflora plays a role.
Indicate their value and the meaning of the definition in humans. Explain the role of hormones thyroid gland in the regulation of basal metabolism
Almost half of all the energy obtained from catabolism is lost as heat during the formation of ATP molecules. Muscle contraction is an even less efficient process. About 80% of the energy used in muscle contraction is lost as heat and only 20% is converted into mechanical work (muscle contraction). If a person does not do work, then almost all the energy generated by him is lost in the form of heat (for example, in a person lying in bed). Therefore, the value of heat production is an exact expression of the value of the exchange in the human body.
To determine the amount of energy expended by the body, direct and indirect calorimetry is used. The first direct measurements of energy metabolism were carried out in 1788 by Lavoisier and Laplace.
Direct calorimetry is the direct measurement of the heat generated by the body. To do this, an animal or a person is placed in a special hermetic chamber, water flows through the pipes passing through it. To calculate heat production, data are used on the heat capacity of the liquid, its volume flowing through the chamber per unit time, and the temperature difference between the incoming and outgoing liquid.
Indirect calorimetry is based on the fact that the source of energy in the body is oxidative processes, in which oxygen is consumed and carbon dioxide is released. Therefore, energy exchange can be estimated by examining gas exchange. The most common method is the Douglas-Haldane method, in which the air exhaled by the person being examined is collected in a bag of airtight fabric (Douglas bag) for 10-15 minutes. Then the volume of exhaled air and the percentage of O2 and CO2 in it are determined.
According to the ratio between the amount of carbon dioxide released and the amount of oxygen consumed over a given period of time - respiratory coefficient(DK) - you can determine which substances are oxidized in the body. DC in the oxidation of proteins is 0.8, in the oxidation of fats - 0.7, and carbohydrates - 1.0. Each DC value corresponds to a certain choleric equivalent of oxygen, i.e. the amount of heat that is released during the oxidation of a substance for each liter of oxygen absorbed in this case. The amount of energy per unit of 02 consumed depends on the type of substances oxidized in the body. The caloric equivalent of oxygen during the oxidation of carbohydrates is 21 kJ per 1 l 02 (5 kcal / l), proteins - 18.7 kJ (4.5 kcal), fats - 19.8 kJ (4.74 kcal).
For indirect definition metabolic rate can be used some physiological parameters associated with oxygen consumption: respiratory rate and ventilatory volume, heart rate and minute volume of blood flow - they all reflect energy costs. However, these figures are not accurate enough.
BX
The intensity of energy metabolism varies greatly and depends on many factors. Therefore, to compare the energy costs of different people, a conditional standard value was introduced - the basal metabolism. Basal metabolism is the minimum energy expenditure for an awake organism, determined under strictly controlled standard conditions:
- 1) at a comfortable temperature (18-20 degrees Celsius);
- 2) in the supine position (but the subject should not sleep);
- 3) in a state of emotional rest, as stress increases metabolism;
- 4) on an empty stomach, i.e. 12-16 hours after the last meal.
Basal metabolism depends on sex, age, height and body weight of a person. The value of the basic metabolism averages 1 kcal per 1 hour per 1 kg of body weight. In men, the basal metabolism per day is approximately equal to 1700 kcal, in women, the basal metabolism per 1 kg of body weight is approximately 10% less than in men, in children it is greater than in adults, and gradually decreases with increasing age.
Daily energy consumption in a healthy person significantly exceeds the value of the basal metabolism and consists of the following components: basal metabolism; working increase, i.e. energy costs associated with the performance of a particular work; specific-dynamic action of food. The totality of the components of the daily energy consumption is the working exchange. Muscular work significantly changes the intensity of metabolism. The more intense the work performed, the higher the energy costs. The degree of energy costs for various physical activities is determined by the coefficient of physical activity - the ratio of total energy costs for all types of activities per day to the value of the basal metabolism. According to this principle, the entire population is divided into 5 groups.
For people doing light work sitting, you need 2400-2600 kcal per day, working with a greater muscular load, 3400-3600 kcal is required, performing heavy muscular work - 4000-5000 kcal and more. In trained athletes with short-term intense exercises, the value of the working exchange can be 20 times higher than the main exchange. Oxygen consumption during exercise does not reflect the total energy expenditure, since part of it is spent on glycolysis (anaerobic) and does not require oxygen consumption.
The difference between the need for 02 and its consumption is the energy obtained as a result of anaerobic decay, and is called the oxygen debt. Consumption of 0^ remains high even after the end of muscular work, since at this time the return of oxygen debt occurs. Oxygen is spent on the transformation of the main by-product of anaerobic metabolism - lactic acid into pyruvic acid, on the phosphorylation of energy compounds (creatine phosphate) and the restoration of 02 reserves in muscle myoglobin.
Eating enhances energy metabolism (specific dynamic action of food). Protein food increases the metabolic rate by 25 - 30%, and carbohydrates and fats - by 10% or less. During sleep, the metabolic rate is almost 10% lower than the basal metabolic rate. The difference between being awake at rest and sleeping is because the muscles are relaxed during sleep. With hyperfunction of the thyroid gland, the basal metabolic rate increases, and with hypofunction, it decreases. A decrease in basal metabolism occurs when the functions of the sex glands and the pituitary gland are insufficient.
With mental labor, energy consumption is much lower than with physical labor. Even very intensive mental work, if it is not accompanied by movements, causes an increase in energy expenditure by only 2-3% compared with complete rest. However, if mental activity is accompanied by emotional arousal, energy expenditure can be noticeably greater. Experienced emotional arousal can cause an increase in metabolism by 11-19% over the next few days.
In the first approximation, the working exchange is two to three times higher than the main one. There are empirically calculated average values of daily energy consumption for people of certain professions. So, for example, a young man of average height and weight, who combines intellectual work and fitness, spends about 3,000 kcal per day. However, such an approximate estimate does not mean anything: two similar people can spend completely different amounts of energy on the same job. That is why one person loses as many extra pounds in a week of training as another person fails to lose with the same load in a month.
Thyroid glands (lat. glandula thyroidea) - endocrine gland in vertebrates and humans, it produces hormones involved in the regulation of metabolism - thyroxine, triiodothyronine, thyrocalcitonin. These hormones contain iodine, so this element is necessary for the normal functioning of the gland.
In an adult, the thyroid gland is located in the anterior region of the neck, in front of the larynx and in the upper part of the trachea.
The thyroid gland produces a number of hormones that are involved in the regulation of growth, development, and tissue differentiation. They increase the intensity of metabolism, the level of oxygen consumption by organs and tissues.
It is now known that the thyroid gland consists of two lobes connected by a narrow isthmus. It is the largest endocrine gland. In an adult, its mass is 25-60 grams.
Thyroid diseases
Myxedema
Cretinism
Goiter Hashimoto
Thyrotoxicosis
Hypothyroidism
thyroid cancer
Basedow's disease
The parathyroid glands, the parathyroid glands, are located on the posterior surface of the thyroid gland. There are four of these glands, they are very very small, their total mass is only 0.1-0.13 g. The hormone of these glands regulates the content of salts, calcium and phosphorus in the blood, with a lack of this hormone, the growth of bones and teeth is disturbed, excitability increases nervous system.
BX one of the indicators of the intensity of metabolism and energy in the body; It is expressed by the amount of energy necessary to maintain life in a state of complete physical and mental rest, on an empty stomach, in conditions of thermal comfort. O. o. reflects the energy expenditure of the body, ensuring the constant activity of the heart, kidneys, liver, respiratory muscles and some other organs and tissues. Released during metabolism thermal energy used to maintain a constant body temperature. Determine in a state of wakefulness (during a dream the level of O. of the lake decreases by 8-10%). O.'s definition about. carried out in conditions of muscle rest; at least 12-16 h after the last meal, with the exclusion of proteins from the diet 2-3 days before the determination of O. o .; at an external comfort temperature that does not cause a feeling of cold or heat (18-20 °). Size O. about. usually expressed as the amount of heat in kilocalories ( kcal) or in kilojoules ( kJ) per 1 kg body weight or 1 m 2 body surface for 1 h or for 1 day. The value, or level, O. o. varies in different people and depends on age, weight (mass) of the body, sex and some other factors. The average basal metabolic rate in a man weighing 70 kg is about 1700 kcal per day (1 kcal for 1 kg weights in 1 h). At women O.'s intensity about. lower by about 10-15%. At newborns O.'s size about. is 46-54 kcal for 1 kg body weight per day and increases during the first months of life, reaching a maximum at the end of the first - beginning of the second year. At the same time O.'s intensity of the lake. the child exceeds O. about. an adult by 1.5-2 times. Then the intensity of O. o. begins to gradually decrease, stabilizing at the age of 20-40 years. At elderly people O. about. decreases. If the calculation of the intensity of O. o. to produce not per unit weight, but per unit area, it turns out that the individual differences in the magnitude of O. o. less significant. Based on the facts indicating the presence of a regular relationship between the intensity of metabolism and the size of the surface, the German physiologist Rubner (M. Rubner) formulated "", according to which the energy costs of warm-blooded animals are proportional to the size of the body surface. At the same time, it has been established that this law is of relative importance and allows only approximate calculations of the release of energy in the body. Against the absolute meaning of the "surface law" is also evidenced by the fact that the intensity of metabolism can differ significantly in two individuals with the same body surface. The level of oxidative processes is determined, thus. not so much heat transfer from the surface of the body as heat production of tissues and depends on the biological characteristics of the animal species and the state of the body, which is due to the activity of the nervous and endocrine systems. Even in the case when all standard conditions for O.'s definition of the lake are observed, intensity of processes of exchange is exposed to daily fluctuations: it increases in the morning and decreases during the night (see. Biological rhythms). Seasonal changes of O. of the lake are noted. in humans: its increase in spring and early summer and its decrease in late autumn and winter. Seasonal changes are associated not so much with temperature factors, but with a change motor activity, fluctuations in hormonal activity, etc. The consumption of nutrients and their subsequent digestion increase the intensity of metabolic processes, especially if the nutrients are of a protein nature. This effect of food on the level of metabolism and energy is called the specific dynamic action of food. To change of level O. about. also lead to prolonged food restriction, excessive food intake, increased or insufficient content in the diet of certain nutrients. Temperature environment also affects the intensity of O. o processes: shifts towards cooling lead to a greater increase in metabolism than the corresponding shifts towards an increase in temperature (with a drop in air temperature by 10 °, the level of O. o increases by 2.5%). O.'s definition about. It has great importance in the diagnosis of certain diseases. On the basis of results of inspection of a large number of healthy people the average O. of the lake is established. - the so-called due O. o. Due O. o. (in kcal for 24 h) is taken as 100% in calculations. Actual O. o. expressed as a percentage of deviation from due upwards with a plus sign, downwards - with a minus sign The permissible deviation from the due value ranges from +10 to +15%. Deviations ranging from +15% to +30% are considered doubtful, require control and monitoring; from + 30% to + 50% are classified as deviations of moderate severity; from + 50% to + 70% - to heavy, and over + 70% - to very heavy. A decrease in metabolism by 10% cannot yet be considered pathological. With a decrease by 30-40%, the underlying disease is required. For definition O. about. using methods of direct and indirect calorimetry. It is necessary to take into account the possibility of discrepancy between the data of direct and indirect calorimetry, which is associated with the short duration of determining oxygen consumption. For longer determinations (about 24 h), the results of both methods should obviously match. Distortion of representation about O. about. may be due to the fact that the caloric value of oxygen is different depending on the nature of the substrates (, fats or), predominantly oxidized in the body in the process of gas exchange a. Size O. about. can be tentatively determined using special clinical formulas (for example, formulas of Reed, Gale, etc.). According to Reid's formula, the percentage of deviation O. o. equals: 75 times plus the difference between systolic and diastolic blood pressure, multiplied by 0.74-72. According to Gale's formula, the percentage of deviation O. o. is equal to: pulse plus the difference between systolic and diastolic minus 111. The general prerequisites for this are the following: counting the pulse, measuring blood pressure should always be carried out only under standard O. o conditions; clinical formulas are not applicable to patients with decompensated diseases of the heart, kidneys and liver, hypertension, atrial fibrillation, paroxysmal tachycardia, aortic valve insufficiency and some other serious diseases and conditions. Pathological. According to existing ideas, the total organism consists of primary and secondary heat. Primary heat is the result of the dissipation of the energy of oxidation of substrates in the electron transport chain, the secondary heat is a consequence of the use of macroergic compounds formed during tissue respiration for a particular cellular function. The main cellular mechanisms of disturbances of O. of the lake. are reduced to a change in the intensity of the formation of primary or secondary heat, or both of its types together. A change in each of these processes is accompanied by a change in oxygen consumption, the most common criterion for O.'s value. In the case of increased consumption of high-energy compounds for various types of cell work, respiratory control in mitochondria comes into force, the essence of which is that the dephosphorylation product is a powerful stimulator of tissue respiration (see Tissue respiration).
With the weakening or complete removal of respiratory control ("loose" coupling or uncoupling of oxidative phosphorylation), increased oxygen consumption is usually recorded. The pathology of the nervous system can cause O.'s change of the lake. both as a result of a direct violation of the formation of primary heat, and as a result of a change in the intensity of the functioning of one or another organ or tissue. An example of the first mechanism is, apparently, lesions of diencephalic vegetative centers (, tumors, hemorrhages, etc.), reproduced in the experiment by "thermal injections" into subcortical formations. The second mechanism causes O.'s decrease of the lake. with paralysis and its increase with increased functioning of the respiratory system, blood circulation, muscles, etc. presumably the liver. Significance of activity changes various bodies for emergence of shifts in O. of the lake. not the same. So, the intense activity of the brain or kidneys has relatively little effect on the overall heat balance of the body, while, as well as the work of the heart and respiratory organs, play a decisive role in the overall heat production of the body. Considerable influence on O. about. renders the autonomic (mainly sympathetic) nervous system, tk. produced by it are directly involved in thermoregulation (thermoregulation). chromaffin tissue (see Chromaffinoma)
secreting and norepinephrine, are followed by sharp increase in O. of the lake. Removal of sympathetic ganglia and adrenal medulla, on the contrary, can reduce O. of the lake. In addition to affecting the function internal organs, these substances, apparently, can also act on the processes of formation of primary heat, but the mechanism of this effect is not yet completely clear. The cause of changes O. o. in various types of endocrine pathology, thyroid diseases are most common, accompanied by increased or decreased secretion of thyroid hormones, which play a specific role in the body as regulators of the intensity of tissue respiration and energy metabolism. O.'s increase about. is the most constant sign of hyperthyroidism that accompanies such endocrine diseases, as toxic, thyrotoxic adenoma, etc. (see Thyrotoxicosis). A decrease in thyroid function (see Hypothyroidism) causes a decrease in basal metabolism. The expressed changes of O. about. observed in the pathology of the anterior pituitary gland, for example, a decrease in O. o. with hypopituitarism (see Hypothalamic-pituitary insufficiency)
or removal of the pituitary gland. The role of other hormones in the genesis of the mechanisms of disturbance of O. o. insufficiently studied. usually accompanied by a decrease in O. of the lake, however, in patients with Addison's disease, its decrease is a non-permanent symptom. of a pancreas reduces O. of the lake. due to its inhibitory effect on catabolic processes. The ability of this hormone to reduce heat production is used in experimental hibernation. Removal of the pancreas, as well as sugar, lead to an increase in O. o., which is probably due not only to the loss of the direct effect of insulin on heat production, but also to metabolic changes, in particular, an increase in the level of free fatty acids and ketone acids, which in high concentrations can inhibit oxidative phosphorylation processes. O.'s changes about. often observed in various intoxications, infectious and febrile diseases. At the same time, the independence of stimulation of oxidative processes from the very fact of the existence of fever was revealed. The most studied is the action of 2,4-α-dinitrophenol, which is considered a classic uncoupler of oxidative phosphorylation. O.'s increase about. during dinitrophenol intoxication, as well as under the action of thyroid hormones, it is characterized by a large increase in heat production, disproportionate to oxygen consumption. Others can raise O. about. either due to uncoupling of oxidative phosphorylation (diphtheria, staphylococcal and streptococcal toxins, salicylates), or due to other, not fully understood causes (for example, endotoxins). There is evidence that O.'s increase in lake, caused by infectious-toxic agents, is associated with the action of thyroid hormones. O.'s increase about. characteristic of the late stages of the development of malignant tumors and especially leukemia. The reasons for this are not fully established, but, apparently, the cellular process itself, as a process accompanied by an increased breakdown of macroergic compounds with an increase in the formation of secondary heat, does not exhaust the mechanisms for increasing heat production in these cases. Hypoxia is usually characterized by O.'s increase of the lake. by increasing the intensity of the activity of the respiratory and circulatory systems, as well as the accumulation of toxic products of interstitial metabolism. However, very severe degrees of hypoxia are accompanied by O.'s decrease in lake. When analyzing the effect of hypoxia, it is necessary to take into account its frequent combination with hypercapnia, since a significant excess of carbon dioxide inhibits heat production. usually proceed with O.'s increase of the lake in which genesis toxic products of a metabolism can play a role. The factor causing change of O. of the lake is long at which mechanisms of sharp restriction of energy expenditures are switched on, leading to decrease in O. of the lake. Bibliography: Drzhevetskaya I.A. Fundamentals of physiology of metabolism and, M., 1977; McMurray U. substances in humans, . from English, M., 1980; Tepperman J. and Tepperman X. metabolism and endocrine system, per. from English, M., 1989; Human Physiology, ed. R. Schmidt and G. Thevs, trans. from English, vol. 4, M., 1986. 1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First health care. - M.: Bolshaya Russian Encyclopedia. 1994 3. Encyclopedic Dictionary medical terms. - M.: Soviet Encyclopedia. - 1982-1984.
See what "Basic Exchange" is in other dictionaries:
The amount of energy expended by an animal or a person at complete rest, on an empty stomach and at a comfortable temperature (for a person 18 20C). Expressed in kJ (kcal) for 1 hour (or 1 day) per 1 kg of weight or 1 m2 of body surface. The main exchange ... ... Big Encyclopedic Dictionary
The amount of energy expended by an animal or a person at complete rest, on an empty stomach and at a comfortable temperature (for a person 18 20 ° C). Expressed in kJ (kcal) for 1 hour (or 1 day) per 1 kg of body weight or 1 m2 of body surface. The main exchange ... ... encyclopedic Dictionary
The totality of metabolic and energy processes occurring in the human or animal body in a waking state, at rest, on an empty stomach, at an optimal (comfortable) temperature. The amount of energy used by the body for... Great Soviet Encyclopedia
BX- rus basal metabolism (m) eng basal metabolism, basal metabolic rate fra métabolisme (m) de base, métabolisme (m) basal deu Grundumsatz (m) spa metabolismo (m) basal … Occupational safety and health. Translation into English, French, German, Spanish
The amount of energy expended by an animal or a person at complete rest, on an empty stomach and at a comfortable temperature (for a person 18-20 °C). Expressed in kJ (kcal) for 1 hour (or 1 day) per 1 kg of body weight or 1 m2 of body surface. O. o. determined at ... ... Natural science. encyclopedic Dictionary
BX- - the minimum amount of energy necessary for the normal functioning of the body in a state of complete rest, with the exclusion of all internal and external influences; expressed as the amount of energy per unit of time, kJ/kg/day; determine in the morning ... ... Glossary of terms for the physiology of farm animals
EXCHANGE OF SUBSTANCES between cells and the environment.
Into the body as part food(bread, meat, vegetables, etc.) nutrients(proteins fats carbohydrates), vitamins, mineral salts, water. released from body cells metabolic end products: CO 2 (excreted by the lungs), H 2 O (excreted by the lungs, kidneys, gastrointestinal tract, skin), urea (excreted by the kidneys) and some others.
THE COMING OF SUBSTANCES into the body is
the amount of substances absorbed in the gastrointestinal tract during digestion (per day).
DIGESTION - the preliminary stage of the assimilation of nutrients.
The basis of digestion is hydrolysis proteins, fats and carbohydrates (BJU) to monomers:
proteins are broken down into amino acids, fats into fatty acids and glycerol, carbohydrates into monosaccharides (glucose, galactose, fructose). Only 1% of nutrient energy is released during hydrolysis. Monomers are absorbed and through the intestinal wall enter the blood, lymph (into the internal environment of the body). The degree of assimilation of BJU is on average 90%. Unabsorbed nutrients are excreted from the gastrointestinal tract in the composition of feces (10%).
CONSUMPTION OF SUBSTANCES in the body - the amount of substances oxidized in the cells of the body (per day).
From the blood, nutrients enter the cells, where intracellular metabolism(intermediate exchange): (1) anabolism– synthesis of new BJU from monomers (plastic function of nutrients); (2) catabolism- oxidation of monomers to CO 2, H 2 O, NH 3 with the release of a large amount of energy: heat, ATP synthesis (energy function of nutrients).
Ammonia (NH 3) is a very toxic substance, therefore less toxic urea is synthesized from it in the liver (excreted by the kidneys).
Substance consumption determined by the end products of catabolism (urine nitrogen) and gas exchange data (oxygen, carbon dioxide) by the Shaternikov method (gross metabolism study).
BALANCE OF SUBSTANCES - the ratio of the income and consumption of substances per day.
(1) Equilibrium balance: the income of BJU is equal to the consumption of BJU.
(2) Positive balance: the input of BJU is greater than the output. In this case, the accumulation of nutrients occurs. Carbohydrates (liver glycogen, muscle tissue - about 400 g) and fats (up to 50% of body weight) can accumulate. There is no accumulation (depot) of protein in the body.
(3) Negative balance: the intake of BJU is less than the consumption (starvation, impaired digestion, absorption in the gastrointestinal tract, etc.)
Protein metabolism
Only proteins contain nitrogen in the composition of amino acid molecules (1 gram of nitrogen is contained in 6.25 grams of protein). Therefore, to study protein metabolism, it is studied nitrogen balance. The arrival of proteins is determined by the nitrogen of food (minus the nitrogen of feces). Protein consumption is determined by urine nitrogen.
positive nitrogen balance can only be in the case of body growth and an increase in the mass of skeletal muscles and other tissues: (1) in children of all ages, (2) in pregnant women, (3) in those recovering from a serious illness and exhaustion, (4) in athletes in the very the beginning of training in the mode of static loads.
Negative nitrogen balance can be with starvation, malnutrition.
In all other cases, a healthy adult must have a condition nitrogen balance(food nitrogen - fecal nitrogen = urine nitrogen).
DAILY REQUIREMENT OF THE BODY FOR PROTEINS:
Wear factor- the amount of the body's own proteins, which is oxidized per day with a protein-free diet with a normal calorie content (due to fats and carbohydrates). Wear factor = 20 g.
Protein minimum- the minimum amount of protein in the diet, at which nitrogen balance is possible. 30 -50 g.(At the same time, the balance is unstable, the state of health is poor).
Protein optimum- the amount of protein in the diet, which not only establishes nitrogen balance, but also ensures high performance, low fatigue, low resistance to infections, joyful mood and good health. 70 - 100 g.
REGULATION OF PROTEIN METABOLISM. (1) Anabolic hormones provide body growth, positive nitrogen balance: a growth hormone(pituitary gland) - protein synthesis, fat oxidation; androgens(adrenal cortex) - protein synthesis, especially muscle tissue; insulin(pancreas) - oxidation of carbohydrates, preservation of proteins.
(2) Catabolic hormones increase protein consumption: glucocorticoids(adrenal cortex) - gluconeogenesis during starvation and stress; thyroid hormones(with a lack of fats and carbohydrates).
FATS METABOLISM (see biochemistry)
The arrival of fats (food fats minus fecal fats). Fat consumption (oxidation in cells; Shaternikov method). Regulation: insulin (accumulation), growth hormone (expenditure), adrenaline (expenditure), thyroid hormones (expenditure).
CARBOHYDRATE METABOLISM (see biochemistry)
The arrival of carbohydrates (food carbohydrates minus fecal carbohydrates). Carbohydrate consumption (oxidation in cells, Shaternikov method). Regulation: insulin (lowers blood sugar), glucagon (increases blood sugar), glucocorticoids (increases blood sugar)
1.Working metabolism, energy costs of the body during various types labor
Muscular work significantly increases energy consumption, so the daily energy consumption of a healthy person who spends part of the day in motion and physical work significantly exceeds the value of the basal metabolism. This increase in energy expenditure constitutes a working increase, which is greater, the more intense the muscular work.
During muscular work, thermal and mechanical energy is released. The ratio of mechanical energy to all the energy expended on work, expressed as a percentage, is called the efficiency. With physical labor of a person, the efficiency varies from 16 to 25% and averages 20%, but in some cases it can be higher.
The efficiency factor varies depending on a number of conditions. So, in untrained people, it is lower than in trained people, and increases with training.
The more intense the muscular work performed by the body, the greater the energy expenditure.
Distribution of the population into groups depending on energy consumption.
The degree of energy expenditure during various physical activities is determined by the coefficient of physical activity (CFA), which is the ratio of total energy expenditure for all types of activities per day to the value of basal metabolism. According to this principle, the entire male population is divided into 5 groups
Group I - knowledge workers. These include: business leaders, teachers, scientists, doctors (except surgeons), writers, journalists, workers in the printing industry, students. Daily energy consumption is kcal for men and kcal for women, i.e. an average of 40 kcal/kg of body weight.
Group II - workers of light physical labor. These include: workers of automated lines, sewers, veterinarians, agronomists, nurses, sellers of manufactured goods, instructors in physical education, coaches. The daily energy expenditure is kcal for men and kcal for women, i.e. an average of 43 kcal/kg of body weight.
Group III - workers of medium severity of labor. These include: surgeons, drivers, workers Food Industry, water transport workers, food vendors. Daily energy consumption is kcal for men and kcal for women, on average per 1 kg of body weight 46 kcal/kg of body weight.
IV group - workers of heavy physical labor. These include: builders, metallurgists, machine operators, agricultural workers, athletes. Daily energy consumption is kcal for men and kcal for women, an average of 53 kcal/kg of body weight.
Group V - persons of especially hard physical labor. These include: steelworkers, miners, lumberjacks, loaders. Daily energy expenditure is kcal for men, averaging 61 kcal/kg. For women, this expense is not standardized.
Specific dynamic action of food
After a meal, the intensity of metabolism and energy expenditure of the body increase compared to their level in conditions of basal metabolism. The increase in metabolism and energy begins in an hour, reaches a maximum 3 hours after a meal, and persists for several hours. The effect of food intake, which increases metabolism and energy costs, is called the specific dynamic action of food.
With protein food, it is the largest: the exchange increases by an average of 30%. When eating fats and carbohydrates, the metabolism increases in humans by 14-15%.
Specifically - the dynamic effect of food is due to:
Energy costs for digestion,
Absorption of nutrients from the gastrointestinal tract into the blood and lymph,
Resynthesis of protein, complex lipid and other molecules;
Influence on the metabolism of biologically active substances entering the body as part of food.
WORK EXCHANGE
Work Exchange- these are the total energy expenditure of the body per day, which are made up of the main metabolism and the working increase.
Working increase is any additional energy expenditure over and above the basal metabolic rate.
Additional energy is spent on (1) physical work, (2) thermoregulation,
(3) digestion of food.
Working increase (per day) = working exchange minus main exchange.
NB! Work exchange depends on sex, age, weight, height and nature of work activity.