When we have been sitting or lying for a long time we can suffer from orthostatic hypotension due to an insufficient operation of the sympathetic nerves.

When we are lying down, the blood pressure in our arteries is pretty much equal throughout the body. When we stand up, the blood pressure is affected by the gravity and increases in the vessels under the heart, while decreasing in the brain. If we lie down again, the blood pressure in the arteries balances once again. If these changes cannot be naturally controlled, then we may suffer an increase or decrease in blood pressure, which could result in a fatal injury.

There are baroreceptors in the walls of main arteries whose tasks are to measure constantly the blood pressure and to send data (electrical signals) to the brain, informing it about the blood pressure in the body. These baroreceptors are located in the aorta as it leaves the heart and in the carotid artery as it enters the brain. With the onset of hypertension, the frequency of the signals that are sent to the brain increases and this drops in case of hypotension. The center of vessel movement in the brain, with regard to the frequency of electrical signals it receives, perceives a low or high blood pressure.

In the brain is a vasomotor center; this continuously controls the blood pressure and regulates it. This center constantly receives data about blood pressure. If the pressure decreases, the signals of the sympathetic nerve increase. If the pressure increases, the signals to the parasympathetic nerves are suppressed. As a result of sympathetic irritability, the heart begins to beat faster and stronger. It pumps much more blood in a unit of time, and thus the blood pressure increases. The arteries and veins also constrict and owing to this constriction in the arteries, the blood pressure increases further. As a consequence of constriction in the veins, the extra blood that is stored inside the veins is pumped into the heart. Now, as the heart is receiving greater volumes of blood, it works faster and contributes to the increase in the pressure. In the meantime, as a result of the suppression of parasympathetic nerve signals, the heart contracts faster and stronger, thus pumping much more blood.

As the blood pressure rises, the mechanism which is in charge of reducing the pressure via vasomotor center is triggered. While pressure is applied to the sympathetic nerves, the signals that are being sent to the heart and vessels decrease. Thus, the rate of systole and the amount of blood which is being pumped decreases. As the arteries receive less blood the volume of blood in the system falls off and as the arteries and veins expand, the blood pressure falls. Due to the dilatation in the veins, the volume of blood which is sent to the heart also decreases and as a result the heart pumps less blood and the blood pressure drops.

However, by triggering the parasympathetic nerves, the signals that are sent to the heart increase. This helps to slow the heart down and ensures that there is less blood pumping through the system. As a result, the blood pressure which has been reduced via the sympathetic system is reduced even further with the parasympathetic system. At this point, it is necessary for there to be a rapid drop in blood pressure, which is provided by the simultaneous functioning of different mechanisms.

We cannot control this system and it acts extremely rapidly and with great elegance. Even in the systole period, when the heart is pumping the blood and there is a short and sudden increase in pressure and in the diastole period, when the heart relaxes and there is a short and sudden decrease in pressure, the system is in charge and functioning at every second, operating to increase the hypotension and to decrease the hypertension. The average healthy human heart beats 70 times per minute. Consequently, there are 70 systole and 70 diastole stages every minute; thus a normal balance can be maintained by decreasing the pressure, which increases 70 times every minute, and by increasing the pressure, which decreases 70 times every minute; this is how the body maintains a normal balance. In other words, this system functions 140 times every minute. Is it possible that this system, which operates throughout our life, a system that we are not aware of, a system that is so sensitive and vital to our lives, a system the details of which have only recently been understood after centuries of observation could be nothing more than a coincidence?

The pressure regulating system mentioned above carries out other important tasks while we are sitting and standing as well. The amount of blood going to the brain is related to the maintenance of a difference in blood pressure between the arteries and veins and to the recirculation of blood. In connection with hypotension, the pressure in the veins to the brain decreases, in order to partially compensate for the decrease in the arteries. By preventing a decrease in the difference of pressure (perfusion pressure) between the two systems, the continuity of blood going to the brain can be maintained.

In addition, a small decrease in the blood going to the brain can lead to an increase in acidity and carbondioxide in the brain tissues and to a decrease in oxygen; this results in the dilatation of the blood vessels in the brain. When these systems go into action anyone who is not suffering from orthostatic hypotension will have a stable amount of oxygen consumption in the brain when they stand up, and thus not experience dizziness.

In fact, scenes from karate movies are wonderful displays of the perfect functioning of this system. In such scenes, the fighter will jump up, and then suddenly fall to the ground; he will then suddenly spring up and performs different moves. Certainly with every movement, the blood pressure changes suddenly, but as a sign of the Creator’s mercy and grace, the body is able to maintain a balance. Should not the person watching these scenes stand in amazement, thinking: “Oh my God, what an incredible order! How great is Your knowledge, power, wisdom and art!”

As mentioned at the beginning of the article with reference to an actual sad incident, when a person whose sympathetic system is not functioning normally suddenly stands up, they can suffer from dizziness and perhaps even faint due to irregular blood pressure.

For patients suffering from orthostatic hypotension patients, it is important that they do not stand up rapidly. In addition, exercises that encourage the use of leg muscles before standing up will help pump blood towards the brain.

Pause for a minute… What would happen if this miraculous system did not exist? Consider how much time it would take you to merely get out of bed every day!

The world hypertension statistics

Almost a quarter (26 percent) of the world’s adult population suffers from high blood pressure. It is estimated that this number will reach 29 percent by the year 2025. These average statistics based on the adult population of the world includes people of various age groups and from different countries. The risk of hypertension increases with age. While the figure for 20–29 year old males is 13 percent, it increases to 40 percent between the ages of 50–59, and reaches over 60 percent after the age of seventy. Although there are slight variations in women, many of the figures are almost the same (Figure 1).

These figures are quite striking; one out of every two people over the age of sixty suffers from high blood pressure. As for those in their seventies, the figures have already reached almost 70 percent and are expected to increase even further as this group ages. Many diseases in the adult population remain at 1–2 percent; therefore, these figures convey just how common and serious hypertension really is.

The regional distribution of hypertension figures

In contrast with the estimated numbers given above, the figures for hypertension in the different regions present significant variations. Statistically, the number of hypertension cases increases according to the welfare status of the society. In economically developed countries, 37 percent of the adult population has high blood pressure, which is a considerably elevated number in comparison with the world average of 26 percent. Furthermore, 70 percent of the males and 80 percent of the females over the age of seventy living in economically developed countries suffer from high blood pressure. However, in economically underdeveloped countries, the number of hypertension cases is very low.

The hypertension rates in China and India are well below the world averages, with males at 17 percent and females at just 14 percent (Figure 2). In some societies, for example in the Amazon’s catchment areas, the Yanomami Red-Indians, and tribes in the highlands of Papua New Guinea, few cases of hypertension can be found, and blood pressure among these groups does not tend to increase with age.

The reasons for the increase in hypertension

There is a genetic disposition to develop hypertension. The recent studies reveal that high calorie foods, a high level of salt intake, the lack of physical activity, and alcohol intake all play a significant role in the increase of hypertension. By examining these reasons alone, we clearly see how important the prohibition of alcohol is and the Prophet’s words of wisdom advising us to eat less bear on our lives and prosperity in both this world and the hereafter.

Excess of body fat (obesity)

Another recent health phenomenon is the huge increase in people suffering from obesity, mainly due to excessive eating and the lack of exercise. Studies related to disease outbreaks (epidemiological studies) show that obesity is clearly associated with hypertension. These studies also reveal a significant increase in people suffering from both obesity and hypertension. According to these studies, 78 percent of the male and 65 percent of the female cases of hypertension are connected to obesity. Similar studies carried out in various countries confirm that a large number of people with high blood pressure were overweight and that losing weight substantially reduced their blood pressure levels. In fact, the blood pressure in some was reduced by losing weight alone, without the need of any medication.

Many studies also evaluated the connection between obesity and hypertension by measuring the level of the leptin, the hormone that controls the appetite, in the body. High levels of leptin induce stimulation in the sympathetic nervous system and shrink the veins (causing an increase in blood pressure). Another reason for the increase in the activity of the sympathetic nervous system of overweight people is the rise in insulin levels, which in most people can be controlled by diet. Finally, the kidneys of overweight people retain greater levels of salt and water, which causes an increase in blood pressure. These conditions, which on many occasions can prove to be very serious, are in fact contrary to the intended physical state of human creation, as the Prophet Muhammad, peace be upon him, declared in these words of warning: “What I fear most for my followers is a large stomach, excessive sleep, idleness, and the lack of certainty (in faith).”

Excessive salt and alcohol

Evidence from both experiments on animals and clinical studies proves that the excessive intake of salt increases blood pressure. In animal experiments, a high intake of salt in the diet of rats showed a rise in blood pressure, which resulted in strokes. In another experiment, more than 0.50 ounces of salt was added to the diet of several chimpanzees for a period of twenty months. The studies showed an increase of 33 mmHg in the systolic blood pressure and 10 mmHg in the diastolic blood pressure, and when the salt was removed from the diet, the chimpanzees’ blood pressure returned to normal levels. Indeed, salt is an important nutrient for the human body. Sodium, potassium, and calcium salts are essential for all nerve cell activity, for muscle movement, and for the osmotic balance of body fluids. Medical science of today stresses the importance of natural foods, and bread, an important part of our diet, meets the body’s daily requirement of sodium. Thus adding salt to our food and exhausting the kidneys is not necessary.

Various clinical studies on humans have shown that excessive salt in the diet increases blood pressure levels. Salt has been used in the human diet for the past 8000 years, since the beginning of agriculture and animal farming. A human’s normal requirement of sodium is 8–10 mmol/per day. However, in economically developed countries, the daily sodium intake of most people has risen to 140–150 mmol per day (8–9 grams), almost 14–15 times more than the normal physiological requirement. In a study carried out on the subject, 10,000 blood pressure sufferers in 32 countries were closely monitored, and the results showed that as the salt intake was reduced, blood pressure levels dropped. In another study, 24 hour urine samples were analyzed, and here too, a low sodium diet showed a decline in blood pressure.

One of the many health risks of alcohol is its serious affect on blood pressure. Clinical studies have proved that the excessive intake of alcohol causes high blood pressure. The frequent cases of high blood pressure in societies of the former socialist countries and economically developed countries of the present are mainly connected to the excessive intake of alcohol.

As a result, the number of high blood pressure cases in the world has exceeded that of contagious diseases, and this is closely connected to our eating and drinking habits. If humans continue to excessively eat and drink as they are at the present, most people will be suffering from high blood pressure in the very near future.