Diseases of the cardiovascular system
What happens when the heart wears out
Nothing makes it possible to predict the risk of developing diseases of the cardiovascular system as well as age. Despite the fact that these diseases can develop at any age, their frequency increases significantly with aging. This group of diseases remains not only the leading cause of death in modern society, but also the main reason why older people cannot tolerate physical exertion necessary in everyday life.
Given the increasing life expectancy of people, we need to better understand how and why the heart and blood vessels (cardiovascular system) age and whether we can slow down the processes involved.
Diseases of the cardiovascular system can lead to myocardial infarction, angina pectoris, heart failure and, eventually, to sudden cardiac death. Diseases of the cardiovascular system include stroke, aneurysm and other diseases of the arteries – vessels that carry oxygenated blood from the heart to other parts of the body.
Most of the items on this list of serious diseases originate from atherosclerosis of the arteries. This condition is characterized by the accumulation of cholesterol, cell breakdown products and inflammation-associated cells in the walls of the arteries, which impedes blood flow. This leads to blood clots blocking the blood flow (thrombosis).
Schematic image and photo of an artery with an atherosclerotic plaque.
What happens to the heart in old age
Is heart wear and tear the cause of aging and death? Is there a timer in our body that counts down the time allotted to a person, or does the body suffer from damage that accumulates over time?
In simple words: the first two factors make a small contribution, while the third factor plays a rather significant role. It is very important that the continuous impact of risk factors for the development of diseases of the cardiovascular system has been ongoing for decades. The use of tobacco products, high blood pressure, abnormal lipid content in the blood and diabetes mellitus gradually damage the walls of the arteries, and the more this exposure continues, the stronger the damage.
The structure and function of the arteries are particularly strongly influenced by aging. The integrity of the arteries is ensured by two important structural fibrous proteins: collagen and elastin.
Collagen molecules are inelastic but durable. It takes over most of the pressure load inside the arteries formed by the contractions of the heart.
According to its name, elastin is elastic and similar in properties to rubber. Its stretching during the contraction of the heart helps to dampen pressure fluctuations inside the arteries. Like rubber, elastin is exceptionally resistant to repetitive stretching and relaxation. However, just like rubber, it eventually wears out and loses elasticity.
Repeated for decades (60-80 times per minute 24 hours a day) contractions gradually lead to a shift in the load distribution, most of which falls on denser collagen and less on softer pliable elastin. As a result, the depreciation of heart beats worsens, which leads to an increase in systolic pressure (the peak value of pressure that occurs when blood is pumped into the arteries).
Blood moves faster through less flexible vessels, so diastolic pressure (the lowest pressure value when relaxing and filling the chambers of the heart) shows a downward trend.
Elderly people with arteries that have lost elasticity are characterized by a large difference between systolic and diastolic pressure. Regular physical activity, a healthy diet and a stable hormonal balance can delay the development of this phenomenon.
What effects does an aging heart have?
High systolic pressure damages the walls of large arteries. Smaller arteries that supply oxygen and nutrients to various organs are subjected to a stronger pulsation of blood flow. Due to the increased pressure, which decreases sharply after each contraction of the heart, they are subjected to a stronger stretching, which disrupts the functioning of their walls. Damage to the small arteries of the brain can lead to multiple micro-strokes, which are one of the main causes of dementia.
Damage to the renal arteries leads to impaired renal function. The kidneys play an important role in regulating blood pressure, so such disorders can trigger a vicious circle in which high pressure contributes to an even greater increase in pressure, and the aggravation of kidney damage leads to the development of kidney failure.
The most susceptible component of the arteries to damage is the inner shell of their walls, which performs a vital function. It not only acts as a barrier between the blood flow and the arterial wall, but also regulates the functioning of the muscle layer of this wall. The latter ensures the expansion or narrowing of the artery, depending on the oxygen demand of the organs.
Under the influence of damaging factors such as tobacco smoke, poor nutrition, diabetes mellitus and other risk factors, this barrier function may be lost, which leads to the deposition and accumulation of various components of atherosclerotic plaques in the vascular wall.
Atherosclerosis of the coronary arteries causes narrowing of the vascular lumen, which can eventually lead to blockage of blood flow. In this case, age is not always a critical factor, but this process worsens with age and the longer the impact of factors, the more likely heart disease develops.
Atherosclerosis is the root cause of the development of most heart diseases that modern people suffer from.
The fact that collagen is the main structural protein of the aging heart causes a decrease in the elasticity of the organ. At the same time, the muscle cells of the heart are replaced not as quickly as they die. Such a weakly elastic heart does not fill up so well, does not empty so well and, accordingly, does not pump blood so well.
Heart failure develops in cases when the alluvial function of the heart is reduced to a level that is not able to provide the blood supply necessary to maintain the vital functions of the body. Fortunately, this happens only after the colossal reserve capacity of a healthy heart is completely exhausted.
Another consequence of these changes is a decrease in the efficiency of the electrical impulses generated by the heart to activate each contraction moving through the heart tissue. This can lead to the development of atrial fibrillation, a form of cardiac arrhythmia that can lead to stroke, especially in the elderly.
Cell aging is a lifelong competition between the processes of production of new and death of old cells. In old age, the death of cells from wear and tear or acute diseases is a test for cellular loss compensation systems.
This mechanism is one of several natural processes that form a timer for the heart muscles. Maintaining physical and mental activity, a conscious attitude to artery-damaging factors, and regular heart health checks are integral components of healthy aging.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of The Conversation: Heart disease: what happens when the ticker wears and tears.
07.03.2017