In life, many hypertension friends often ask such a question when seeking medical treatment: [Why does my blood pressure rise? ]
To be honest, At the present stage of medical development, no medical bull can tell you exactly the specific reason for the increase in blood pressure. In order to [cover up] our ignorance, we use [primary hypertension] to refer to 90% ~ 95% hypertension. The remaining 5% ~ 10% hypertension, we find that they are caused by other diseases, and correspondingly call them [secondary hypertension].
Although we have not yet been able to find out the cause of hypertension for every friend with hypertension, in terms of physiology, the medical field is continuously deepening its research on how normal blood pressure is maintained stable. Here, we might as well have a brief understanding.
Blood Volume Affects Blood Pressure
If there is no water in the water pipe, it is impossible to generate water pressure at all. Similarly, the blood volume in the circulatory system, especially in the arterial system, is directly related to the level of blood pressure. If a person loses a lot of blood and causes shock, the blood vessels are in a collapsed state, and the blood pressure naturally decreases.
If a person ingests too much salt, or if there is something wrong with his kidney, he cannot expel excess salt and water from the body in time, and his blood vessels are filled with too much blood volume, his blood pressure will rise accordingly.
Heart Strength Affects Systolic Blood Pressure
Systolic blood pressure is the larger number and the smaller number when measuring blood pressure, which is diastolic blood pressure.
We all know that the heart pumps blood into the arteries in its continuous beating, thus [irrigating] the large and small blood vessels of the whole body. In medicine, the amount of blood emitted by the heart every beating is called [stroke volume]. The total amount of blood emitted by the heart into the arteries every minute is called [cardiac output].
The more blood returns to the heart when the heart relaxes, the more strong the heart contracts, and the more times the heart beats, the greater the cardiac output.
It is not hard to imagine that each time the heart contracts, the more blood is injected, the greater the pressure on the arterial wall, and the systolic blood pressure will increase accordingly. However, when the heart relaxes, the blood stored in the arterial blood does not increase significantly, so the stroke volume has little effect on diastolic blood pressure.
Heart rate affects diastolic blood pressure
The speed of heartbeat is called [heart rate]. The increase of heartbeat frequency reduces the diastolic [relaxation] time of the heart. In this way, every time the heart is in diastolic period, there is still too much blood remaining in the blood vessels, thus causing the diastolic pressure of the blood vessels to increase.
When we exercise, our cardiac output increases. For people or athletes who exercise regularly, the main way to increase cardiac output is to increase the stroke volume of the heart. For people who do not exercise normally, the main way to increase cardiac output is to increase heart rate. It can be imagined that if we measure blood pressure during exercise in these two groups of people, we may find that the systolic blood pressure of athletes changes more than that of ordinary people, and the diastolic blood pressure of ordinary people changes more than that of athletes.
Arterial Elasticity Affects Systolic Blood Pressure
The aorta has some elasticity, The moment the heart contracts, A large amount of blood poured into the aorta, The arteries will be enlarged, The worse the elasticity of the arteries, The more limited the volume of blood vessels can be held up, the more pressure the same volume of blood can be forced to squeeze in a smaller space, the greater the pressure on the blood vessel wall, and the higher the systolic blood pressure. When the heart relaxes, the diastolic blood pressure decreases because the less elastic aorta does not have enough retraction force to maintain the diastolic blood pressure.
With the increase of age, aorta begins to scleroze, which leads to the increase of arterial systolic pressure and pulse pressure difference. This also explains why hypertension in the elderly is mostly simple systolic hypertension. At present, most people at home and abroad regard pulse pressure difference > 63 mmHg as the risk limit for atherosclerosis formation.
Peripheral blood vessels affect diastolic blood pressure
When the heart relaxes, The blood filled in the large artery continues to flow to the small and medium arteries through the elastic retraction force of the large artery. Then [irrigate] the capillary bed of the whole body. During this process, if the resistance of the peripheral blood vessels, especially the small and medium arteries, increases, the blood flow from the large artery to the small and medium arteries will decrease or slow down, thus increasing the amount of blood remaining in the large artery during diastole and increasing diastolic blood pressure.
The resistance of peripheral blood vessels is mainly related to the diameter of blood vessels. When people are nervous, the smooth muscle contraction of arteriole wall increases and the diameter decreases, causing the resistance to increase and diastolic blood pressure to increase.
Blood pressure fluctuations are very complicated.
In daily life, the fluctuation of blood pressure is far more simple than what we analyzed above.
Many factors such as blood volume, stroke volume, heart rate, arterial elasticity and peripheral blood vessels do not work together, but are related and affect each other. What is uniformly deployed for them is the complex neurohumoral regulation mechanism in our body.
The blood pressure of healthy people is basically constant in daily life, but it is not the same. In life, we all have this experience more or less: emotional excitement, mental stress, exercise and other factors will make blood pressure rise.
I wonder if you have any such experience: if the doctor measures your blood pressure to be too high during the physical examination, you will be allowed to go out and relax for 10-15 minutes before repeating the measurement? The reason is to eliminate the influence of tension.
Someone has done such an experiment: Let a group of teenagers play stimulating video games. As the game progresses, their blood pressure increases compared with that in a quiet state. After the game ends, the kidney sodium excretion speed of normal teenagers increases, and the blood pressure quickly returns to the normal state, while the kidney sodium excretion speed of obese teenagers is slower, and the blood pressure recovery is also slower.
This experiment tells us: We judged that a person’s blood pressure was normal, This is not to say that his blood pressure has always been at a normal level, but to say that the rise of blood pressure has not become a normal state and has not caused damage to organs. Anyone’s blood pressure will rise under certain stimulation, but thanks to the regulation of human nerves and body fluids, blood pressure always tends to be normal, and after the stimulation factors are relieved, blood pressure will quickly return to its normal state.
However, for patients with hypertension, Blood pressure is above normal for a long period of time, This shows that the body’s ability to control blood pressure has changed. Although we still cannot fully understand the mechanism of these changes and can only call this part of hypertension [essential hypertension] in general terms, some risk factors leading to hypertension are already certain facts, such as obesity, alcohol and tobacco, heredity, etc.