What is hypertension?
It is an increase in the tension or pressure exerted on the heart above the healthy limit. In other words, hypertension is also high blood pressure. This hyper pressure or tension often reflects in the blood vessels such as arteries. To understand the concept of hypertension, we must consider the heart as a machine that pumps blood round the body. Each time it contracts, it pumps a certain amount of blood round through the arteries and veins. As the blood is pumped out of the heart by a force, it exerts an amount of pressure as it passes through the blood vessels. There is a range of values for the normal heart beat. However, conditions arise when the pressure exceeds the normal range. That is when we say an individual has a high blood pressure, or is hypertensive.What is the healthy range?
Values for the normal blood pressure vary with different sources. However, a range of 100mmHg-140mmHg for the systole (the value above in the fraction) and 60mmHg-90mmHg diastole (the value below in the fraction) is widely used. When you check your blood pressure, you are going to be given a value like 110/80. The value above represents the pressure in the vessels when the heart contracts and the value below represents the pressure when the heart relaxes.Can Obesity cause Hypertension?
In addition to being caused by a number of other factors, one common cause of hypertension is obesity. To the lay man, obesity means being fat or heavy. Clinically, obesity is determined by a standard of comparison called the body mass index (BMI). I will talk about how to determine whether you are obese or not later.Obesity actually results from the accumulation of excess fat deposits in the body. When we eat food, it gets digested and the nutrients are stored in our body. Depending on our energy demand, that is, how active we are, we may not be able to exhaust this energy store by the time we are taking our next meal. So with time, there is a gradual but steady accumulation of the excess nutrients in our body. Where the nutrients are fats, they are stored around the kidneys and under the skin.
However, fats are not stored in those areas alone. As they are deposited under the skin, they also get stored in the walls of the blood vessels. This causes a narrowing of the passage in these vessels. Let us consider the blood vessels to be pipes or narrow tubes through which the heart pumps blood round the body. When fats deposit in their walls, it is like adding another layer of material to the inside of the tubes which makes them narrower. Now, because the tubes are narrower, the volume of blood that passed through them freely during one heart beat before would have difficulty doing so. Therefore, each time the heart contracts, there is increased pressure in these vessels and the heart does more work to overcome the resistance in order to pump blood. This places extra load on the heart and in the long run may lead to heart failure.
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