The physiological basis of work activity and exercise презентация

Physiological changes in the body during work
are related to the type and nature of the activity.
Types of employment:
Physical labor.
Brainwork.
Nervous and stressful work.

Physical labor
is characterized by a load on the muscular system.
* Varies in severity: light, medium, heavy, and very heavy.
* The severity of labor is determined by energy costs.

The severity of labor characterizes
only the physical component of labor and is determined by :
1.- energy expenditure of the body,
2.- the nature of labor movements,
3.- severity of vegetative shifts.

Energy costs depending
on the severity of physical labor are:
I-light labor - up to 2.5 kcal/min,
II-medium - 2.5 – 4.1 kcal/min,
III-heavy – 4.1 – 6.0 kcal/min,
IV-very heavy-more than 6.0 kcal/min.

Mental work is accompanied
by emotional and motor components.

Nervous and stressful work.
It includes work with a high degree of danger or responsibility for the results of work.

The intensity of the work.
Reflects the load on the Central Nervous system and is characterized by:
1. the volume of the perceived information,
2. speed of changing parameters of command signals,
3. state of analyzer systems,
4. expression of emotions,
5. the degree of attention tension.

Labor groups
are classified according to the intensity of attention:
1. based on the percentage of work duration,
2. requiring concentration,
3. of the total duration of work.

Labor groups
The following groups are distinguished:
1. - non-strenuous work-up to 25%;
2. - low stress –up to 50%;
3.- intense – up to 75%;
4.- very stressful -more than 75%.

Work and performance.
WORK is a purposeful activity involving the use of the neuromuscular system or neuropsychic activity.

PERFORMANCE
is the potential or actual ability of a person to perform :
1. maximum possible amount of work,
2. with a certain quality,
3. for a given time.

Factors that determine performance.
Internal:
1. training,
2. the value of the functional reserves,
3. features of transport and metabolic functions,
4. emotional background.

External Factors :
1. working conditions,
2. temperature,
3. illumination,
4. noise,
5. vibration,
6. air composition,
7. shift work,
8. mode of work and rest.

CHANGE IN HEALTH.
As a rule, performance fluctuates during the day, week, month, year. These fluctuations are close to sinusoidal.
Improving PERFORMANCE is carried out by training coordination systems, as well as processes of transport and metabolic maintenance of activity.

PHYSICAL PERFORMANCE and WORKING RESULTS DURING THE HOUR, DAY(a), WEEK (b)

DETERMINATION OF PHYSICAL PERFORMANCE

1. By minute oxygen consumption:
A) Determines aerobic performance,
B) Gives an idea of internal respiration, i.e., the work of the respiratory, cardiovascular systems and tissue respiration,
C) the Indicator allows you to evaluate the transport and metabolic support of functions;

2. By the amount of work for a certain time;
3. On indicators of physiological systems in the performance of labor operations.

4. Method of metered physical activity.
A) Stargallery or PWC170- test
(Full symbol is POWER WORKING CAPACITY 170). IT allows you to determine the potential performance, provided that the pulse of the subject reaches 170 per minute.

B) examination on the treadmill.
This is running on a track driven by a motor.

C) Bicycle Ergometry.
When conducting such a survey, the amount and duration of the load is dosed.
CCC indicators are studied: heart rate, blood PRESSURE, and ECG is continuously recorded.
Oxygen consumption can be quantified.

D) Measurement of muscle strength
on a dynamometer (for different muscle groups).

PRINCIPLES for assessing MENTAL PERFORMANCE include:
1) determining the amount of short-term memory;
2) determining the sustainability of attention;
3) determining the productivity of mental labor;
4) features of thinking.

TRAINING RULES.
1) more than 1/3 of the body's muscles are subjected to stress;
2) it is necessary to dose loads by intensity and duration;
3) the amount of loads should increase gradually (by 2-5 %).

DYNAMICS OF EXPENDITURE AND RECOVERY OF ENERGY RESOURCES with SUPERCOMPENSATION

OPTIMALLY SELECTED TRAINING MODE:
1) ensure the economization of functions, even at rest (↓ heart rate, respiratory rate, IOC, BP);
2) improves the integral indicators of the body: appetite, sleep, mood;
3) there is a "cross" effect of adaptation, i.e. immune responses are activated,
4) increases resistance to external temperature fluctuations,
5) improves mental performance.

STAGES OF ADAPTATION TO WORK
ADAPTATION is manifested in the form of forming a working dynamic stereotype, i.e., memorizing the sequence of actions of stimuli.

WORKING DYNAMIC STEREOTYPE
Pavlov I.P. held that the interaction of higher organisms with the external environment was based on the dynamic stereotype, that is on the integration in the cortical hemispheres of neural traces coming from the external and internal environments.
Theory postulated the synthesis of conditioned reflexes.

It is a system of reflexes, a new program, formed in the process of labor activity.
At the first stage, irradiation of excitation occurs, an increase in the activity of all functional systems.
In the process of adaptation to work, concentration takes place, a new functional system is formed-a working dynamic stereotype.

The working dynamic stereotype is triggered by an irritant (tools, object of labor, situation).
The implementation of actions on this stereotype does not cause emotional stress, does not require increased attention.

FATIGUE
is a temporary decrease in performance that occurs after work.
It disappears after a rest.

DEPENDING ON THE TYPE OF WORK,
THERE ARE TYPES OF FATIGUE:
1) physical fatigue;
2) touch ( in the analyzers);
3) mental. It is caused by a large amount of information, a lack of time, and a degree of creativity;
4) emotional.

FACTORS THAT AFFECT THE DEVELOPMENT OF FATIGUE.
CRITERIA FOR FATIGUE:
1.Objective, 2.Subjective.

OBJECTIVE CRITERIA
are related to change:
a) constants of the internal environment, CNS indicators, and other physiological systems ;
b) reflex time;
C) the nature of responses to tests, etc.

d) Electromyograms for fatigue
1. normal muscle
2. fatigue muscle

SUBJECTIVE CRITERIA:
a) Fatigue is a subjective psychosensory state.
It depends on the emotional support of the work process (boredom leads to fatigue).
It is manifested in the desire to stop working or reduce the load.
The feeling of fatigue is not necessarily associated with the burden of work,
b) Fatigue is accompanied by numbness of the shoulders and neck.
There are lower back pain, blunted vision.

THEORY OF FATIGUE
• 1) Information. Fatigue develops as a result of impaired perception, processing, and control processes in analyzer systems.
• 2) Violation of power supply. Fatigue is caused by a lack of macroergs and hypoxia, which occurs due to a violation of the transport of O2 to the working organs during prolonged work.

Regularities of fatigue development
in departments of analyzer systems based on information theory.
• 1) at the receptor level. It is associated with a violation of the conditions for generating the receptor potential (violation of the ion channels).

2) at the level of synaptic processes:
a) decrease in the probability of releasing the mediator during long-term synapse operation;
b) reduced sensitivity of postsynaptic receptors;
C) changes in the properties of synapse esterases that destroy the mediator;
d) violation of energy supply processes in the synapse.

3) at the level of the nerve centers.
• As a result of long-term work, the process of processing information, making the right decision, and activating other centers is disrupted.
That is, the management process is disrupted.

4) fatigue may develop in the Executive body.
For example, during physical work, the composition of the microenvironment and the sensitivity of the muscles to control signals changes, the response time slows down, and the nature of the response itself changes.

CHRONIC FATIGUE
occurs if the recovery of the body's resources after previous work has not occurred, i.e. fatigue has become chronic.
In this case, there is an overstrain of the processes of regulation of functions.
It is necessary to fight overwork, because this leads to an increase in the incidence of diseases, and a decrease in employee performance.

Recovery of HEALTH occurs:
1.With passive rest,
2. With active rest.

ACTIVITY OF SYSTEMS AIMED AT FIGHTING FATIGUE.
1. The development of fatigue largely depends on the energy reserves, the speed of their mobilization, the duration of action and the power of energy sources.

2. The development of fatigue is hindered:
a) Increased blood flow and delivery of O2 to the organ using reserves of the cardiovascular and respiratory systems;
b) Increase the CAKE COOK in the tissues;
c) Increasing the body's resistance to hypoxia.

3. Coordination of transport and metabolic
support activities is carried out:
1) sympathoadrenal system;
2) conditional and unconditional reflexes
first part END.
© SAVKIN V.V.at all.,PSMU,2020 ,1 & 2 parts

Sports Physiology
Second Part:

Work and Sport Physiology

Sports Physiology
In fact, if some of the extremes of exercise were continued for even moderately prolonged periods, they might be lethal.
Therefore, sports physiology is mainly a discussion of the ultimate limits to which several of the bodily mechanisms can be stressed.
To give one simple example: In a person who has extremely high fever approaching the level of lethality, the body metabolism increases to about 100 percent above normal. By comparison, the metabolism of the body during a marathon race may increase to 2000 percent above normal.

Muscles in Exercise Strength, Power, and Endurance of Muscles
The final common determinant of success in athletic events is what the muscles can do for you-what strength they can give when it is needed, what power they can achieve in the performance of work, and how long they can continue their activity.
To give an example of muscle strength, a world-class weight lifter might have a quadriceps muscle with a cross-sectional area as great as 150 square centimeters. This would translate into a maximal contractile strength of 525 kilograms

The power of muscle contraction
is different from muscle strength because power is a measure of the total amount of work that the muscle performs in a unit period of time.
The maximal power achievable by all the muscles in the body of a highly trained athlete with all the muscles working together is approximately the following: First 8 to 10 seconds=7000,
Next 1 minute=4000;
Next 30 minutes=1700 kg-m/min.

Another measure of muscle performance is endurance
This, to a great extent, depends on the nutritive support for the muscle-more than anything else on the amount of glycogen that has been stored in the muscle before the period of exercise.
The amounts stored are approximately the following:
High-carbohydrate diet=40;
Mixed diet=20;
High-fat diet=6 g/kg muscle.

Muscle Metabolic Systems in Exercise
These systems are
(1) the phosphocreatine-creatine system,
(2) the glycogen-lactic acid system, and
(3) the aerobic system.
The source of energy actually used to cause muscle contraction is adenosine triphosphate (ATP).
Each of these bonds stores 7300 calories of energy per mole of ATP under standard conditions

The amount of ATP present in the muscles, even in a well-trained athlete, is sufficient to sustain maximal muscle power for only about 3 seconds, maybe enough for one half of a 50-meter dash.
Therefore, except for a few seconds at a time, it is essential that new ATP be formed continuously, even during the performance of short athletic events.

The slide shows the three metabolic systems that provide a continuous supply of ATP in the muscle fibers.

1. Phosphocreatine can easily provide enough energy to reconstitute the high-energy bond of ATP. Furthermore, most muscle cells have two to four times as much phosphocreatine as ATP.
The energy from the phosphagen system is used for maximal short bursts of muscle power (8-10 s).

2. Glycogen-Lactic Acid System
The stored glycogen in muscle can be split into glucose and the glucose then used for energy. The initial stage of this process, called glycolysis, occurs without use of oxygen and, therefore, is said to be anaerobic metabolism (Energy is released to form four ATP molecules for each original glucose molecule, then it is transformed to lactic acid).
Under optimal conditions, the glycogen-lactic acid system can provide 1.3 to 1.6 minutes of maximal muscle activity

3. Aerobic System
The aerobic system is the oxidation of foodstuffs in the mitochondria to provide energy.
That are glucose, fatty acids, and amino acids from the foodstuffs-after some intermediate processing-combine with oxygen to release tremendous amounts of energy that are used to convert AMP and ADP into ATP.
Unlimited time (as long as nutrients last).

Recovery of the Muscle Metabolic Systems After Exercise
And then energy from the oxidative metabolism of the aerobic system can be used to reconstitute all the other systems-the ATP, the phosphocreatine, and the glycogen-lactic acid system.
Reconstitution of the lactic acid system means mainly the removal of the excess lactic acid that has accumulated in all the fluids of the body. This is especially important because lactic acid causes extreme fatigue.

Energy resources of skeletal muscle

Recovery of the Aerobic System After Exercise
Even during the early stages of heavy exercise, a portion of one's aerobic energy capability is depleted.
This results from two effects:
1) the so-called oxygen debt and
2) depletion of the glycogen stores of the muscles.

Oxygen Debt

The body normally contains
about 2 liters of stored oxygen that can be used for aerobic metabolism even without breathing any new oxygen. This stored oxygen consists of the following:
(1) 0.5 liter in the air of the lungs,
(2) 0.25 liter dissolved in the body fluids,
(3) 1 liter combined with the hemoglobin of the blood, and
(4) 0.3 liter stored in the muscle fibers themselves, combined mainly with myoglobin, an oxygen-binding chemical similar to hemoglobin.

In heavy exercise,
almost all this stored oxygen is used within a minute or so for aerobic metabolism.
Then, after the exercise is over, this stored oxygen must be replenished by breathing extra amounts of oxygen over and above the normal requirements.
In addition, about 9 liters more oxygen must be consumed to provide for reconstituting both the systems.
All this extra oxygen that must be "repaid," about 11.5 liters, is called the oxygen debt.

Effect of Athletic Training on Muscles and Muscle Performance
One of the cardinal principles of muscle development during athletic training is the following: Muscles that function under no load, even if they are exercised for hours on end, increase little in strength.
At the other extreme, muscles that contract at more than 50 percent maximal force of contraction will develop strength rapidly even if the contractions are performed only a few times each day.

Importance of Maximal Resistance Training.

Along with this increase in strength is an approximately equal percentage increase in muscle mass, which is called muscle hypertrophy.
In old age, many people become so sedentary that their muscles atrophy tremendously.
In these instances, muscle training often increases muscle strength more than 100 percent.

Respiration in Exercise
Oxygen Consumption and Pulmonary Ventilation in Exercise
Normal oxygen consumption for a young man at rest is about 250 ml/min.
However, under maximal conditions, this can be increased to approximately the following average levels:
1. Untrained average male=4000 ml/min;
2.Male marathon runner= 5100 ml/min.
Maximal breathing capacity=150-170 L/min
(in rest = 5 L/min).

Effect of Smoking on Pulmonary Ventilation in Exercise
It is widely known that smoking can decrease an athlete's "wind.“ This is true for many reasons.
First, one effect of nicotine is constriction of the terminal bronchioles of the lungs.
Second, the irritating effects of the smoke itself cause increased fluid secretion into the bronchial tree, as well as some swelling of the epithelial linings.
Third, nicotine paralyzes the cilia on the surfaces of the respiratory epithelial cells that normally beat continuously to remove excess fluids and foreign particles from the respiratory passageways.

A recording of muscle blood flow in a period of 6 minutes during contractions.

Cardiovascular System in Exercise
This Figure shows a recording of muscle blood flow in the calf of a person for a period of 6 minutes during moderately strong intermittent contractions.
The great increase in flow-about 13-fold-but also the flow decrease during each muscle contraction.

Two points can be made from this study: (1) The actual contractile process itself temporarily decreases muscle blood flow because the contracting skeletal muscle compresses the intramuscular blood vessels; because of lack of delivery of enough oxygen and other nutrients during the continuous contraction.

(2) The blood flow to muscles during exercise increases markedly.
Muscle blood flow can increase a maximum of about 25-fold during the most strenuous exercise.
Almost one-half this increase in flow results from intramuscular vasodilation caused by the direct effects of increased muscle metabolism.

Work Output, Oxygen Consumption, and Cardiac Output During Exercise

Work Output, Oxygen Consumption, and Cardiac Output During Exercise
The normal untrained person can increase cardiac output a little over fourfold, and the well-trained athlete can increase output about sixfold.
The heart-pumping effectiveness of each heartbeat is 40 to 50 percent greater in the highly trained athlete than in the untrained person, but there is a corresponding decrease in heart rate at rest.

Cardiovascular System in Exercise the marathon runner.

Figure shows the changes
in stroke volume and heart rate as the cardiac output increases from its resting level of about 5.5 L/min to 30 L/min in the marathon runner.
The stroke volume increases from 105 to 162 milliliters, an increase of about 50 percent, whereas the heart rate increases from 50 to 185 beats/min, an increase of 270 percent.
Therefore, the heart rate increase accounts by far for a greater proportion of the increase in cardiac output than does the increase in stroke volume during strenuous exercise.

Cardiovascular System (heart rate) in Exercise

Heatstroke
During endurance athletics, even under normal environmental conditions, the body temperature often rises from its normal level of 98.6° to 102° or 103°F (37° to 40°C).
With very hot and humid conditions or excess clothing, the body temperature can easily rise to 106° to 108°F (41° to 42°C).
At this level, the elevated temperature itself becomes destructive to tissue cells, especially the brain cells.

When this happens, multiple symptoms begin to appear, including extreme weakness, exhaustion, headache, dizziness, nausea, profuse sweating, confusion, staggering gait, collapse, and unconsciousness.
The treatment of heatstroke is to reduce the body temperature as rapidly as possible.

Body Fluids and Salt in Exercise
As much as a 5- to 10-pound weight loss has been recorded in athletes in a period of 1 hour during endurance athletic events under hot and humid conditions.
Replacement of Sodium Chloride and Potassium

Body Fitness Prolongs Life
Multiple studies have now shown that people who maintain appropriate body fitness, using judicious regimens of exercise and weight control, have the additional benefit of prolonged life.
Especially between the ages of 50 and 70, studies have shown mortality to be three times less in the most fit people than in the least fit.