Physical activity and heart.
I am receiving many letters with the request to tell about the impact of sport and physical education at heart. However, pondering this topic, I found it necessary to expand the scope of our conversation and to discuss the impact of exercise in General. In fact, you see, sometimes physical labor in the garden of exhausting not less than a good workout, however, say, Olympic sports, this activity will be included, probably not soon.
Thus, we will consider the question broadly, but do not forget about sport. So, for readability, we highlight three types of physical activity:
static, in which there is continuous strain of muscle groups (for example, forced working posture in which you have to spend a certain time), dynamic when in groups of muscles alternating tension and relaxation (e.g., walking, running, swimming) and “explosive”, characterized by very strong and short-term muscle tension (for example, lifts weights). There are also mixed types, and physical inactivity (lack of any kind of loads, except, of course, minimal muscular activity). Your parsing we start with the dynamic types of load, then it will be easier to deal with other species.
Dynamic loads can be low, medium and high intensity. What happens in the body at low dynamic load (e.g. when walking)? Working muscles require more oxygen so the heart increases its reduction and quickens them. Cardiac muscle is trained, it activates metabolism, and enhanced recovery processes. Activates the hormones of the adrenal glands and the thyroid gland (and with obesity, for example, this system has always oppressed in varying degrees), increasing the combustion of carbohydrates, increases assimilation of the muscles of oxygen. Activate a special system providing hypotensive (reduces blood pressure) action (trigger feedback mechanisms: because the heart has to work harder, HELL, respectively, will increase and the body includes mechanisms aimed at reducing AD.
And since the load is small, then the AD will be insignificant, but the hypotensive reaction processes, since it started, always goes quite intensively). In addition, the vessels passing in the muscles during rhythmic muscle work, then compressed, then released from compression. You know? The muscles that tighten the blood vessels, pushing out from the blood, then let them go. allowing the vessels to engorge with blood. How would we get the second “muscle” heart, which helps our heart, unloads it (now I understand why even patients with myocardial infarction and heart failure are recommended for a leisurely walk?). Moreover, improve the properties of the blood, reduces the clumping of platelets, increases the content of high density lipoprotein (it’s practically the only substance that can dissolve cholesterol, dropped out in plaque, and “pull” it from the plaque). Now let’s see what happens if the load increases and becomes more intense.
If physical activity increases the body’s need for energy supply are higher. Increasing the consumption of oxygen (as oxygen is a necessary substrate for the reproduction of energy). If the source of energy, basically, was “burning” of carbohydrates, now as an energy source turns out to be fats. “Burning” of fat starts with about 15 – 20 minutes of work.
Hence the conclusion: if You need to lose weight, the extra calories or received from food excess cholesterol, physical activity must be at least 20 minutes before basically “burn” carbohydrates. Increased blood pressure, pulse rate, blood levels of adrenaline and other stimulating hormones. If this load continues for too long (how long is the question of health status, age, training, etc.), the heart and the entire body get a good coaching load. Moreover, it is believed that only such a load (increased requirements to the body) to develop adaptive capacity of the organism.
Repeatedly entering this mode, the heart is more adaptable to this mode and produces a more economical and optimal variant of its activities. But if we further increase the load? Unfortunately, at a certain stage of growth of the load ceases to give an adequate increase in the health of the heart. Ie you increase the load, and the coaching effect is not increased, there comes the so-called “plateau” of the load. If You continue, in spite of everything, the build-up of stress, there comes a time when the cells of organisms are generally not able to provide excessively increased need for energy and chemicals, primarily oxygen.
Comes oxygen limit”, at which the load begins to destroy the body: there is damage to the muscular system, heart, blood vessels, brain, broken gas, protein, carbohydrate, fat, hormonal and other types of metabolism, etc. (well-known disease of athletes known as myocardial due to physical stress, belongs to this class of diseases). It is important to be able at least to estimate their physical abilities. To these we now turn.
To determine the physical working capacity (and accordingly to determine the person’s physical exertion) there are various ways, from the most simple and rough to high precision, but is complicated and requires special equipment. The simplest method for batching of the loads is the definition of maximal and submaximal heart rate. Maximum heart rate is called heart rate, which corresponds to the heart that produces the maximum consumption of oxygen by working muscles.
Ie me remind you, when the muscles of their increased need for oxygen and consequently, the oxygen consumption of adequately increasing. But muscles are not unlimited and pretty fast oxygen comes a limit beyond which the muscle is no longer able to absorb sufficient quantities of oxygen required for the job. If the load continues to grow and now you have a variety of damage to muscle cells. There are special tables that define the maximum heart rate for each age, but there is known to the simplified formula: 220 – age (i.e. if You are 45, Your maximum heart rate equals 220 – 45 = 175). Submaximal heart rate is calculated as 75 or 85 percent of maximum. It corresponds to twisting loads (see previous issue).
Let’s make a deal, people having heart problems, submaximal heart rate set at 75%, the people, trained and healthy, can be considered a submaximal heart rate at 85% of the maximum allowed. Thus, it is clear that the maximum health effect we get when the load corresponding to the submaximal heart rate, and in any case, the load should not give a pulse exceeding the maximum allowable level. In addition, for the evaluation of fatigue loads (i.e. load criteria – low, medium, high) are applied and simplified, yet effective scheme for determining the external signs of fatigue. They are summarized in the table, which I bring to your attention.
Before, to consider identifying individual exercise performance, it is necessary to tell about two other methods of determining physical performance, more complicated, but gives more reliable information. This is, firstly, double the work.