The term “primary” is a term often used in medicine, which means that the cause is not clearly identified. It is the most common type of hypertension. However, the final diagnosis of primary hypertension requires the exclusion of secondary hypertension (i.e., hypertension that has a cause and can be treated for that cause). According to statistics, primary hypertension accounts for 90% to 95% of the entire hypertensive population, and secondary hypertension accounts for 5% to 10%. The latest survey data show that there are about 300 million hypertensive patients in China, and the number of new hypertensive patients increases to about 10 million every year, so the research on the causes of hypertension and prevention is urgent.
It is now accepted that hypertension is a cardiovascular syndrome caused by many known or unknown causes and is in a state of constant progress and change, which can lead to changes in the function and structure of the heart, brain, kidney and blood vessels, and eventually cause serious complications such as stroke, heart failure and kidney failure. Is such a large group of primary hypertension “primary”?
First, let’s understand how blood pressure is formed.
Blood pressure is the pressure of blood against the walls of blood vessels and depends mainly on the cardiac output and the peripheral vascular resistance of the body circulation.
Mean arterial pressure = cardiac output x total peripheral resistance.
Cardiac output: increases with the volume of body fluids, heart rate increases, myocardial contraction increases, and cardiac output increases.
Total peripheral vascular resistance is related to the following factors.
1, structural changes in the small arteries of resistance, such as thickening of the vessel wall, increased fibrous components, and vascular sclerosis, resulting in a sustained increase in peripheral resistance.
2, decreased compliance of the vascular wall (especially in the aorta), resulting in increased systolic pressure, decreased diastolic pressure, and increased pulse pressure difference.
3, vascular diastolic and contraction state disorders: for example, sympathetic excitation, alpha receptor agitation, increased secretion of angiotensin, endothelin and other substances, so that vasoconstriction, resistance increased; nitric oxide, prostacyclin, bradykinin, cardiac natriuretic and other substances make vasodilation, resistance decreased.
4, increased blood viscosity also increases peripheral vascular resistance.
Blood pressure is also regulated through the following two pathways.
1, immediate regulation: mainly through pressure receptors, sympathetic nerve activity to achieve.
2. Chronic regulation: mainly through the renin-angiotensin-aldosterone system, and the regulation of body fluid volume by the kidneys.
Therefore, the formation, stabilization and regulation of blood pressure involve multiple systems such as cardiovascular, neurological, endocrine, renal, blood and mental-emotional, which determines the complexity of the occurrence of hypertension and the diversity of its causes.
So, what are the possible causes of primary hypertension?
1, poor lifestyle habits.
Including irregular living, diet, emotional disorders, emotional overstimulation, improper work and rest, as well as staying up late, eating late night snacks, drinking too much carbonated beverages, eating a lot of convenience foods, sitting by the computer for a long time, head down to play cell phones, resulting in visual fatigue, brain excitement, all these bad habits contribute to the occurrence of hypertension.
2, unreasonable diet.
Especially high sodium and low potassium diet, daily sodium intake exceeds 5-6g per day recommended by the World Health Organization (including hidden salt), and potassium intake is less than 3g per day. too much saturated fatty acids in the diet: for example, more in animal fats, less in vegetable fats, and least in vegetables and fruits. Too low intake of unsaturated fatty acids and too much intake of foods containing trans fatty acids: for example, margarine foods, all kinds of western pastries, chocolate pies, coffee mates, convenient instant foods, etc. Unsaturated fatty acids are easy to produce trans fatty acids after high temperature or repeated heating. There is also excessive intake of sodium and sugar drinks.
3, overweight and obesity.
Overweight obesity often cause hyperlipidemia, blood viscosity increases, triglycerides rise, high-density lipoprotein decline, a variety of inflammatory factors are activated, release; too much free fatty acids cause insulin resistance; increased body fat, obesity causes excessive body burden, the body needs more energy, the heart must increase the work, output more blood than normal weight, to meet the body’s metabolic needs. Over time, blood pressure will then become higher and higher.
4, long-term heavy alcohol consumption.
According to statistics, 5-10% of hypertensive patients are due to excessive alcohol consumption. The incidence of hypertension increases with the increase of alcohol consumption in the drinking population. Each gram of alcohol contains 7 kcal, which is one of the most calorie-rich foods; at the same time, drinking large amounts of alcohol can cause gastric dilation, increase the intake of sodium and salt due to the tastelessness of the mouth, and cause obesity due to excessive calories. Observation found that a small amount of alcohol after a short period of blood pressure drop, but then will rise; large amounts of alcohol can also stimulate sympathetic excitation, heart rate increases, so that blood pressure rises and fluctuations increase.
5, long-term mental tension.
Due to the rapid development of society, increased competitive pressure, work pace increases, interpersonal tension, so that social groups generally feel increased mental stress. People in a state of tension, panic, anger, depression, anxiety, irritability, etc., prone to depression, anxiety, excessive emotional changes cause the cerebral cortex excitation – inhibition balance imbalance, sympathetic nerve activity increased, while neuroendocrine dysfunction, platelet activity reactivity increased, blood viscosity increased, prompting the occurrence of hypertension.
6, sleep disorders.
Including long-term insomnia and sleep apnea syndrome, especially the latter, according to statistics 35%-50% of friends with sleep apnea syndrome are accompanied by hypertension, but also persistent hypertension. One of the causes of morning peak hypertension, because the airway obstruction ventilation disorders caused by hypoxemia, activation of the sympathetic nervous system, renin angiotensin system, increased secretion of catecholamines in the blood vasoconstrictor substances, while the cerebral cortex excitation – inhibition central dysfunction, accelerating the occurrence of hypertension.
7, sedentary, physical activity is not enough.
Due to the speed and convenience of modern life, the car as a substitute for walking, computers, television has become a tool for people’s daily work, sitting still, lack of exercise more and more people. Especially adolescents, research shows that moderate exercise can regulate the human renin angiotensin aldosterone system, balance the sympathetic – parasympathetic nerve function, increase the secretion of vasodilator substances, improve the function of vascular endothelial cells, promote glucose and lipid metabolism, prevent and slow the occurrence of hypertension.
8, smoking.
Including their own smoking and passive smoking. Pregnancy smoking has a greater impact on the fetus, and is one of the causes of hypertension in adolescents later. Tobacco in the harmful substances into the blood caused sympathetic excitation, enhanced oxidative stress, damage to vascular endothelial cells, prompting increased secretion of vascular endothelin, vascular tension and contraction, increased pressure; also make changes in the structure of the blood vessel wall, accelerating atherosclerosis, increased blood pressure. Nicotine and other harmful substances directly damage the cardiovascular system of the fetus through the placenta, making the child more likely to develop hypertension in adulthood.
Some hypertension is also treated as primary hypertension because the current diagnostic methods are not yet able to clarify its cause. In fact, it is secondary hypertension, only we have not been able to discover its exact cause, for example
(1) Adrenal hypertension: Although no adrenal hyperplasia or tumor is detected by enhanced CT, MRI, or ultrasound, elevated aldosterone, cortisol, and epinephrine on laboratory tests do not require surgery and are treated mainly with medication.
(2) Renal hypertension: It refers to the presence of a certain degree of lesion, slight sclerosis and stenosis in the renal artery, renal artery trunk, first and second branches of the internal renal artery, collateral renal artery, glomerular and tubular arteries, etc., which cannot be detected by the current common examination means only.
(3) Obstructive sleep apnea syndrome: 5%-10% of hypertension is due to this syndrome, and blood pressure will drop when symptoms improve.
(4) Metabolic syndrome: is due to poor lifestyle causing obesity, elevated triglycerides, decreased HDL, high blood sugar, and excessive waist circumference, called metabolic syndrome. As the above indicators improve, blood pressure will also decline.
(5) Simple systolic hypertension in the elderly: manifests as elevated systolic blood pressure, decreased or low diastolic blood pressure, high sodium and low potassium. It is due to atherosclerosis, decreased elasticity or increased blood volume of large arteries.
(6) Sympathetic over-activation hypertension in young and middle-aged people: manifesting as palpitations, panic, hand tremors, flushing, chest discomfort, vague pain, rapid heart rate, elevated diastolic blood pressure and normal or slightly elevated systolic blood pressure during physical examination. This is due to increased sympathetic excitability and increased secretion of adrenaline and other catecholamines.
(7) Systolic hypertension in adolescents: There can be no symptoms or only slight head swelling. Often, elevated blood pressure is found during physical examination, mainly due to elevated systolic blood pressure, while diastolic blood pressure is normal. The reason is that the endothelium of blood vessels is damaged and the secretion of substances that constrict the blood vessels increases a lot, while the secretion of substances that diastenate the blood vessels decreases, resulting in vasodilation and contraction dysfunction and elevated blood pressure.
From the above analysis, it can be seen that the so-called primary hypertension actually has a cause, but the current medical science has not yet developed to the precise location, the most advanced examination instruments can not find the traces of organ and tissue lesions, so “primary” is relative. In addition to doctors helping you analyze and judge the cause of hypertension, and doing related laboratory tests, more causes of hypertension have to rely on the patients themselves to find, to change their own bad lifestyle, self-adjustment mentality; to understand the relevant knowledge of hypertension, to play their own initiative, and to cooperate with doctors to control their blood pressure. It is believed that only when the causes are removed can the occurrence of hypertension be completely reduced and the blood pressure be truly and effectively controlled.