Why does the heart contract?

What makes our heart work tirelessly? After all, just think, receiving impulses from the conduction system, this organ pumps blood 24 hours a day. And this process has no respite from the moment it starts in the prenatal period! This is amazing. There are several answers, but they are not exhaustive.

Recent studies by Swedish scientists allowed them to conclude that hydraulics play a vital role in the repeated contraction of the chambers, and they called the diastole phase the most important factor in the work of the heart.

We will focus on what is scientifically substantiated and has long been known about the heartbeat. The conduction system of the heart plays a major role in the contractions of the atria and ventricles. Starting from the right atrium and passing from the atria to the ventricles, the conduction system ensures the flow of impulses to the chambers of the heart in the same order.

This circumstance ensures the conditions for the correct and coordinated work of that body. The conduction system has the sinus node, internodal tracts, atrioventricular node, His bundle with its branches and Purkinje fibers. Among this entire system, there are 4 main sources of impulses - the so-called “pacemakers”. The main one, the sinus node, produces impulses with a frequency of 60 to 80 impulses at rest per minute.

If the sinus node malfunctions, the pacemaker becomes the atrioventricular node, capable of producing impulses with a frequency of 40 to 60 impulses per minute. The next pacemaker in descending order is the bundle of His with its branches. It is characterized by generating pulses with a frequency of 15-40 pulses per minute. If for some reason the His bundle does not work, the Purkinje fibers begin to set their own rhythm - no more than 20 beats per minute.

2 Main indicators of the cardiovascular system

In the work of the heart, the main indicators are identified that influence its functional state, as well as the state of the body as a whole. They are all interconnected. Let's continue what we started talking about. Heart rate (HR) or heartbeat is one such indicator of its functioning. Heartbeat is of great importance, because rapid heartbeat can lead to depletion of blood supply to the heart muscle, and this is fraught with the development of ischemia and all the ensuing consequences.

A slow heartbeat can lead to decreased blood flow to the vessels of the brain. This situation is dangerous due to the development of oxygen “starvation” of the brain. When studying heart function, heart rate at rest is taken into account. How many beats per minute should the heart beat in an adult and a child? These indicators may differ so much that for an adult patient the normal heart rate level in a child is tachycardia, etc. So, there is a norm of indicators.

3 Heart rate depending on age

1. In the prenatal period, a normal heart rate is considered to be from 120-160 heart beats per minute.
2. During the neonatal period (up to one month, 29 days), the normal heart rate is considered to be from 110 to 170 heartbeats per minute.
3. From one month to a year, heart rate indicators range from 102 to 162 contractions per minute.
4. From one to two years, the heart rate level decreases to 154 beats at the upper limit and 94 beats at the lower limit.
5. The next age period is from two to four years. The normal heart rate for a child at this age is 90 - 140 heartbeats per minute.
6. At four to six years old, normal heart rate showed - from 86 to 26 heartbeats per minute.
7. At six, seven and eight years old, 78-118 beats per minute is normal for a child.
8. From the 8-year to 10-year period, the normal heart rate is from 68 to 108 beats per minute.
9. At 10-12 years of age, the normal limit for children is between 60 and 100 beats per minute.
10. At 12-16 years old, this indicator decreases to 55 beats per minute at the bottom and 95 beats per minute at the top.
11. From 16 to 50 years, the boundaries of normal heart rate are within 60-80 beats per minute.
12. From 50 to 60 years of age, normal heart rate is considered to be from 64 to 84 beats. per minute in an adult patient.
13. From sixty to eighty years of age, normal heart rate is between 69 and 89 beats per minute.

Heart rate can be determined by palpation of the radial or carotid artery. Determination of the pulse on the radial artery in a healthy person corresponds to the heart rate. Palpation of the radial artery is performed by pressing the pads of the four fingers on the outer (lateral) surface of the hand. The thumb should be on the back of the hand. This method of determining the pulse should not cause difficulties.

If the radial artery lies deep or subcutaneous fat is pronounced, you can try to determine the pulse on the carotid artery. However, when determining the pulse in this way, you should be careful, since strong pressure can cause a decrease in blood pressure. The place for determining the pulse on the carotid artery is the lateral surface of the neck. It is necessary to turn your head as far as possible to the side. Due to this, an oblique contour of the neck muscle appears on the lateral surface of the neck.

By drawing a line from the upper edge of the thyroid cartilage (Adam's apple) to the anterior edge of this muscle horizontally, you can feel the pulsation of the carotid artery, after which you can determine the pulse. It is worth remembering that the pulse may not always coincide with the heart rate. This phenomenon is called pulse deficit. The volume of blood ejected by the ventricles does not reach the peripheral arteries. In such cases, the number of heart contractions exceeds the pulse rate in the peripheral arterial vessels. Pulse deficiency can be observed with atrial fibrillation and extrasystole.

4 Systolic volume

The next main indicator of the functioning of the human heart is systolic or stroke volume of blood (SB, SV). It represents the volume (portion) of blood that the ventricles eject into the vessels during the systole phase. CO is an indicator that can vary depending on gender, age, and the functional state of the body. It is logical that during the physical period this figure increases, since working muscle mass must be supplied with additional blood volume.

Let's start with normal indicators of systolic blood volume in children:

1. During the neonatal period, a stroke volume of 2.5 ml is considered normal;
2. By the year this figure increases to 10.2 ml;
3. At 7 years of age, a normal volume of CO is considered to be 28.0 ml;
4. In children aged 12 years, the figure continues to rise and is 41.0 ml;
5. From 13 to 16 years of age, blood volume is 59.0 ml.

The normal values ​​for stroke or systolic blood volume vary between children and adults. For men, this figure is 65-70 ml per systole, for women - 50-60 ml per systole. However, not all of the blood in the ventricles is released into the vessels. The resting systolic blood volume may be one-half or one-third of the total blood volume in the ventricle. This is necessary so that at the time of physical activity the ventricles have a reserve supply needed by the body.

Therefore, at the moment of physical or emotional overload, the human heart is capable of increasing the stroke volume by 2 times. Both the right and left ventricles should have approximately the same systolic volume. In other words, the portion of blood ejected by the ventricles must be the same. Blood CO can be calculated based on minute blood volume and heart rate (HRF). The IOC divided by the heart rate will be the systolic or stroke volume of blood.

5 Minute blood volume

The minute volume of blood is the portion of blood that the ventricles eject into the vessels per unit time. In other words, it is the product of systolic or stroke volume and heart rate. IOC, like CO or SV, depends on age, gender, resting state or load:

1. For newborns, normal IOC is within 340 ml;
2. For children aged one year it is 1250 ml;
3. At 7 years, the IOC is 1800 ml;
4. In children aged 12 years, the IOC is 2370 ml;
5. By the age of 16, the IOC indicators for girls are 3.8 l, for boys - 4.5 l;
6. In adults, the normal IOC value is 4-6 liters.

With increasing load on the cardiovascular system, the IOC can increase to 30 liters per minute. In people involved in sports, IOC indicators can reach 40 liters per minute under conditions of physical activity.

Heart rhythm is a certain periodicity of myocardial contractions. It depends on the impulses that arise in the sinus node. The normal heart rate at rest is 60-100 beats per minute. Under certain conditions, this indicator changes up or down and depends on many factors. This article talks about normal heart rhythm and also indicates the reasons for its abnormalities.

Features of heart contraction

Contractions of the heart muscle occur under the influence of impulses that are formed in a special conduction system. The main pacemaker is the sinus node. Under its influence, the heart contracts regularly and rhythmically (that is, at regular intervals). In this case, contraction of the myocardium causes oscillations of the arteries (pulse), which can be determined on the radial artery. Under certain conditions, the frequency and rhythm of heart beats changes. In this case we talk about arrhythmia.

It is worth noting that certain changes in heartbeat are observed in healthy people. A respiratory arrhythmia occurs, in which inhalation is accompanied by an increase in heart contractions, and exhalation, on the contrary, is accompanied by a certain bradycardia, that is, a decrease in the number of heart beats. A slowdown in heart rate is observed in older people, during sleep, and also in well-trained athletes (often their heart rate can be as low as 40 beats per minute).

In addition, during physical or emotional stress, so-called physiological tachycardia can be observed. This is a change in heart rhythm in which the number of myocardial contractions increases. Other reasons for this condition:

• Change of microclimate. Sudden changes in temperature, oxygen concentration or atmospheric pressure can affect the heart rhythm.
• An increase in body temperature is always accompanied by a certain tachycardia. Thus, with an increase in temperature by 1°C, the heart begins to contract faster by approximately 10 beats.
• Drinking alcohol, coffee and some medications is also accompanied by changes in heartbeat.
• In women during pregnancy, physiological tachycardia is also recorded, which is associated with an increased load on the body and an increase in the amount of circulating blood.
• When you overeat, your heart also starts beating faster.

Heart rhythm is influenced by factors such as age and gender. At birth, a child’s heart rate is considered to be 140 beats; over time, this figure decreases and amounts to 100-110 beats. With age, the number of heart contractions decreases and until adolescence is established at the level of normal levels for an adult.

By age, the pulse changes on average by 5 pulsations for every 5 years of life. This pattern can be associated with the aging of the body and the need for faster blood movement to provide internal organs with nutrients and oxygen.

Thus, up to 30 years of age, the normal pulse averages 70 beats, in 50-year-old people it increases to 80 beats, and at the age of 60-70 years it already reaches 90 beats per minute. However, this pattern is not necessary.


If we talk about the characteristics of the heart in men and women, it is worth noting that in representatives of the stronger sex, the heart normally contracts somewhat more slowly. Women tend to experience some tachycardia compared to men because their hearts are much smaller and therefore have to contract at a faster rate for the body to function properly.

What is the feature of heart rate measurement?

The pulse of a healthy person fluctuates throughout the day. The lowest rates are recorded at night. During the daytime, heart rate increases. Body position has a certain influence on the work of the heart. When lying down, the pulse is low, but if you sit or stand up, it increases slightly. Given these features, in order to find out the normal level of heartbeat for a particular person, measurements should be taken at the same time and in the same position.

It is recommended to determine heart rate in the morning, without getting out of bed. You should not conduct such a study after eating, when taking certain medications, or after drinking alcohol. The results will be unreliable in cases where a person experiences acute hunger or wants to sleep.

After physical overexertion, sex or massage, taking a bath or during menstrual periods, as well as when exposed to cold or sun, the examination results may not correspond to real values.

In addition, in weather-sensitive people, during magnetic storms, blood pressure fluctuates (it decreases), and this in turn affects the contractile function of the heart (heart rate accelerates). For reliable measurements, it is necessary to eliminate the influence of all factors that can change the frequency of contractions of the heart muscle.

The rate of heart beats depends on many factors. In cases where a patient has a heart rate of 100 beats, but does not have a feeling of heaviness in the chest, dizziness, weakness, shortness of breath or other symptoms of tachycardia, then this heart rhythm can be considered normal.

The same applies to bradycardia in trained people. The heart can adapt to regular physical activity. With constant training, blood circulation and energy consumption change. This happens in order to maintain high performance under excessive loads.

In this case, myocardial hypertrophy (increase in its volume) is observed, as a result of which adequate blood circulation is ensured in fewer heartbeats. This physiological athletic heart restores its original shape when the load is reduced. In the absence of deterioration in health, such changes are adaptive in nature and are the norm.

Pathological changes in heartbeat

Changes in cardiac activity in some cases are a very serious disorder and require immediate treatment. An increase in heart contractions, which is pathological and does not go away on its own, is usually associated with conditions such as:

Pathological bradycardia is mainly recorded in the following cases:

• changes in the sinus node, which provoke so-called sinus bradycardia;
• dysfunction of the atrioventricular node;
• other changes in the conduction system, leading to the development of various blockades.

Similar disorders are observed against the background of heart attacks, acute coronary syndrome, cardiosclerosis and arterial hypertension. Among the causes of bradycardia, one should also recall kidney damage, medication, thyroid pathology in the form of hypothyroidism, fasting and various poisonings. In children, bradycardia is recorded in the presence of heart defects, after severe infections, with excessive growth and poor nutrition.

If you have general weakness, cold sweat and fatigue, as well as loss of consciousness and the appearance of spots before your eyes, you should consult a doctor. Bradycardia is a dangerous condition, as it can lead to a sharp decrease in blood pressure, the development of coronary artery disease, or even provoke cardiac arrest.

When answering the question of how many heart beats should be normal, it is worth remembering that the contractility of the myocardium is influenced by many external and internal factors. What matters are age and gender, the degree of physical development, the state of the autonomic and endocrine systems, the presence or absence of pathologies of other organs or systems, and the state of the conduction system in the heart. The individual characteristics of a particular patient’s body also matter.

To prevent the development of serious complications that heart rhythm disturbances can lead to, you need to periodically undergo medical examinations, and if you have certain complaints, immediately contact a cardiologist for examination and prescription of the necessary treatment.

Every person knows that physical activity, mental stress, and emotional outbursts affect the body. Sometimes you can hear the opinion that a human organ that constantly experiences significant physical stress wears out faster. After all, the heart has to beat more often, it does not rest. Is this really true? Are there any rules? How many beats per minute should the heart beat? Does its performance change under constant loads?

Strengthening the work of our “internal engine” can occur due to the release of a large portion of blood into the artery with each contraction. If the number of cycles increases, this also leads to increased cardiac activity. Which of these techniques, forcing the most important organ to work harder, is more beneficial for him - this has long been a matter of debate among doctors.

The heart of an untrained man

The muscle of this organ of an untrained person is weak, so it is unable to push out a large volume of blood. This fact has long been known to everyone. In this case, blood circulation can be increased only by increasing heart rate. With this way of working the heart, the pause time is reduced. But the muscle of the “internal engine” should receive rest during this period of time. This means that the heart of an untrained person gets tired quickly, but gets little rest. With significant physical exertion, the increase in its performance occurs no more than 3 times and only due to heart rate.

How does a trained organ work?

In trained people, the increase in heart performance occurs most of all due to an increase in the volume of blood ejected into the aorta. Therefore, the rest time of this organ almost does not decrease, and it has time to rest. Under very high physical exertion, a trained heart can increase its performance in two ways. Firstly, due to the stroke volume (2 times). Secondly, due to heart rate (3 times). Total - increase in efficiency by 6 times.

Heart training rules

This will be useful for each of us to know. When an untrained person immediately begins heavy loads, this leads not only to a general painful state, but also to oxygen starvation. And all human organs, including the heart, are sensitive to a lack of oxygen.

At the same time, it is known that weak loads do not produce a training effect. Therefore, the intensity of exercise must not only be gradually increased, but also dosed correctly.

Active work of the heart during training provides it with the opportunity to contract less frequently during rest. This mode of operation is most beneficial for restoring activity.

When performing exercises for training, it is important to know how many beats per minute the heart should beat, and depending on this, adjust the load. Many do not attach much importance to this aspect, and in vain.

Heart response to dosed load

With a simple test, anyone can find out to what extent their “inner motor” is trained. To do this, first count the number of heart beats per minute at rest. You can perform 3-4 measurements and find this indicator. Then they perform 20 squats, after which they immediately record how many heart beats per minute they counted. Such measurements are performed every 20 seconds for 3 minutes. All indicators must be recorded. Next you need to carry out a small test. The results are considered good if the heart rate after the load increased by one third or became less than the readings at rest. If the heart rate per minute increases by half, then the result is average. And when the indicator is more than half, the result can be considered unsatisfactory.

What heart rate is considered normal?

So how many beats per minute should your heart beat? This indicator primarily depends on the state of human health. It is believed that the healthier he is, the lower the heart rate result. It may depend on other factors, for example, age, fitness, the presence of load at the time of measuring the pulse, medication taken, body position, air temperature.

In an adult aged 18 years or more, the heart rate ranges from 60 to 100 beats per minute. For a trained athlete, it can be 40 beats; for cycling champions, the figure was 22. In children of different ages, heart rate ranges from 160 to 75 muscle contractions.

Does health depend on heart size?

The result of training and a healthy lifestyle can be a strong, resilient, big heart. But it turns out that the increased mass of this organ does not always indicate that it has become more resilient and efficient.

An increase in heart mass can also be found in alcohol lovers and people leading a sedentary lifestyle. The muscles of the organ are gradually destroyed, and in their place connective tissue is formed, which is filled with fat. Such a layer cannot contract, so the heart, although large, still works weakly and is susceptible to various diseases.

To prevent vascular diseases, every person must know how many beats per minute the heart should beat, how to calculate this indicator, and how to regulate it. For these purposes, you can purchase a special device that is placed in the chest area using a special strap. Heart rate is measured continuously, so you can get reliable data on the work of the heart over a certain period of time.

I wonder how many beats per minute should the heart of a healthy person beat? The number of heart contractions, depending on various factors, is considered the main indicator of the health of the body. The main organ of the human body functions as a pump, pumping up to 130 ml of blood per contraction. During the day, it is capable of pumping about 7500 liters of blood fluid. The speed of blood moving from the left ventricle to the aorta is about 40 km/h. Disturbances in its work are fraught with negative consequences for the entire body.

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Normal heart rate

A small number of beats is considered a positive sign, which indicates the ability of the heart to pump the required volume of blood in a small number of contractions. It is believed that the fewer beats per minute the heart muscle produces, the stronger the body. A slow heart rate is also observed in a sleeping person, when the need for oxygen and nutrients decreases. The wear and tear of the heart and the gradual weakening of the heart muscle cause the number of heartbeats to increase every year. A normal heartbeat is usually equal to the number of years lived. At age 70, the normal heart rate is 70 beats per minute..

The number of heartbeats is determined using a special medical device. You can measure your heart rate yourself by feeling with your fingers a large artery located in the neck or wrist. People of different ages have different heart beats per minute:

• up to a year of life - 120-140;
• children's hearts of different ages can contract at a speed of 75-160 beats per minute;
• The normal number of heart beats in adults is 60-100 units;
• a man's heart beats a little less frequently than a woman's heart;
• the trained heart muscle of an athlete makes 40-46 contractions per minute;
• the number of heartbeats in stressful situations or heavy loads can reach 200 units;
• Cycling champions recorded 22 beats per minute.

By studying the melody of the heart with special computer programs, scientists were able to reveal some of the secrets of the work of the main organ. It was determined that the heart rate of a healthy body is slightly chaotic, it is characterized by either acceleration or delay. The pre-infarction state of the body can be determined by studying the work of the heart. In this case, the heartbeat rhythm is extremely accurate. Such knowledge helps determine a person’s predisposition to heart disease.



What affects heart rate?

Changes in heart rate can sometimes cause some concern. The way the heart beats is influenced by the following factors:

• emotional tension, anxiety and worries;
• genetics;
• rapid fatigue of the body;
• training;
• hormonal imbalances;
• weakening of the heart muscle due to illness or age;
• heart and nervous system diseases;
• colds;
• poisoning;
• viral diseases;
• climatic conditions of the external environment;
• inflammation in the body.

Heart problems contribute to weakness, headaches, fatigue and feelings of tension.





Dependence of performance on training

To find out what is the explanation for the different performance of the main cardiac organ in a healthy person, you need to understand the work of the heart in trained and untrained people. The heart muscle of an untrained body is weakened, so it cannot pump a large amount of fluid in one contraction. To pump the required volume, the heart speeds up. As a result, it reduces the pause time during which the muscle rests. It follows from this that the muscle of an untrained body quickly gets tired, and it is given a short period of time to rest. If such an organism is subjected to great physical stress, then an increase in the body’s performance is achieved only by accelerating the work of the heart, and no more than 3 times.



The functional abilities of a trained heart are much higher due to the sufficiently large amount of blood fluid released per contraction. A sufficient period of time is allocated for resting the heart muscle, so it receives complete rest. Increased performance under increased loads is carried out using 2 methods:

• increase in the volume of pumped liquid by 2 times;
• acceleration of the pace of work by 3 times.

As a result, the performance of the main organ can be increased 6 times if it is trained.





Heart training

A sharp increase in the load on an untrained organ can lead not only to general malaise, but to oxygen starvation of the body, which will affect all organs, including the heart. Small constant loads also do not give the desired effect. In this regard, to train the heart muscle, it is necessary to give an optimal load with a gradual increase.

The activity of the heart muscle during training will allow it to contract less during rest.

This mode of operation of the heart is productive for restoring its activity. When performing various exercises that train the heart organ, it is important to know the heart rate and, in accordance with this information, control the amount of load. This aspect should not be neglected, since failure to comply with this rule can lead to unpleasant consequences.



Test to determine the condition of the heart muscle

To determine the degree of training of the main organ, it is necessary to perform the following manipulations, the results of which will need to be immediately recorded on paper:

1. 1. Calculate your pulse for a minute at rest.
2. 2. Perform 20 squats.
3. 3. Count the number of beats per minute immediately after the exercise.
4. 4. Repeat the process of measuring pulse after every 20 seconds for 3 minutes.
5. 5. Compare the results obtained.

The result can be considered remarkable if the frequency of contractions after the load increases by 1/3. An increase in the number of heartbeats by half indicates an average result. If people’s heart rate after training is more than half, then the result is considered unsatisfactory.

The number of heart beats per minute is called the pulse.Pulse- this is one of the main medical indicators. It is usually customary to talk about the pulse asabout the number of beats per minute. This makes it quite convenient to compare indicators with average values ​​and with each other.

In an adult in a calm, relaxed state, the pulse ranges from 60 to 80 beats per minute, that is, a little more often than one beat per second. You can measure your pulse using medical devices or manually by placing your fingers on one of the easily palpable arteries - for example, in the wrist or neck.

Heart rate changes

The pulse is never the same. It changes from external factors: air temperature and humidity, pressure, wind and much more. Also, changes in heart rate can be internal sensations, emotions, and even unexpected changes in mood.

In newborn babies, the heart rate is twice as high as normal - about 140 beats per minute. This is completely normal. During the first year of life, it begins to gradually decline. By about six years of age, the average normal heart rate of a child is already 100 beats per minute. The normal value - from 60 to 80 beats per minute - the pulse acquires only by the age of 16-18 years.

Arrhythmia

Arrhythmia refers to instability of the heart rhythm. Simply put, the heart beats sometimes less often, sometimes more often. Thus, the pulse is sometimes higher, sometimes lower. When this happens without any reason, on its own, then they talk about arrhythmia.

It should be noted that if, with a normal pulse, it is enough to count the number of heart beats in 30 seconds and then multiply the resulting value by two, then with arrhythmia, for greater accuracy, the pulse should be measured for a full minute.

Tachycardia and bradycardia

Two more deviations from the norm are associated with changes in heart rate. If a person's heart rate is generally higher than normal - for example, 90, 100 or even more - this is called tachycardia. If the heart beats less frequently than necessary, this phenomenon is called bradycardia.

Both tachycardia and bradycardia can be individual characteristics of the body, or they can be signs of a disease. As a rule, changes in heart rate are associated with the functioning of the cardiovascular system, as well as with the characteristics of pressure in the body.