Hypertension (High Blood Pressure)

Dr Chakshu *

Pain in acute myocardial infarction (front) :: Pix - JHeuser/Wikipedia

Every year, 17th May is observed as World Hypertension Day. Hypertension is one of the world's great public health problems and a leading cause of death. The basic goal of World Hypertension Day observation is to promote public awareness on hypertension and to encourage citizens of all countries to prevent and control this silent killer.

What is blood pressure?

Blood pressure is simply the physical pressure of blood in the blood vessels. It is similar to the concept of air pressure in a car tyre. When your heart beats, it pumps blood round your body to give it the energy and oxygen it needs. As the blood moves, it pushes against the sides of the blood vessels. The strength of this pushing is your blood pressure. Blood pressure is measured in 'millimeters of mercury' (mmHg) and is written as two numbers. For example, if your reading is 120/80mmHg, your blood pressure is '120 over 80'.

What is Hypertension?

Hypertension (HTN or HT), also known as high blood pressure, is a long term medical condition in which the blood pressure in the arteries is persistently elevated. When you have your blood pressure taken, the result is given as two numbers – the maximum and minimum levels. For example: 110/80mmHg. The first or top number is the highest level your blood pressure reaches when your heart is squeezing. This is called your systolic blood pressure level.

The second or bottom number is the lowest level of your blood pressure when your heart is relaxing between beats. This is called your diastolic pressure.

To have high blood pressure, your blood pressure must be consistently equal to or higher than 140/90mmHg over a number of weeks. One or both readings can be high, either the first, systolic reading (the pressure as the heart pumps blood around the body) or the diastolic one (as the heart relaxes and refills with blood).

What is normal blood pressure?

Blood pressure can be classified into several categories as per the following table.

1. Normal blood pressure is systolic pressure less than 120 and diastolic pressure less than 80 mmHg.
2. "Prehypertension" is systolic pressure of 120 – 139 and diastolic pressure of 80 – 89 mmHg.
3. Stage 1 Hypertension is systolic pressure of 140 – 159 and diastolic pressure of 90 – 99 mmHg.
4. Stage 2 Hypertension is systolic pressure of 160 or greater and diastolic pressure of 100 or greater.

How do I know if I have high blood pressure?

High blood pressure often doesn't have any symptoms, so you usually don't feel it. For that reason, hypertension is usually diagnosed by a health care professional during a routine checkup. If you a close relative with hypertension, or other risk factors, it is especially important to pay attention to your blood pressure reading. If your blood pressure is extremely high, you may have unusually strong headaches, chest pain, difficulty in breathing, or poor exercise tolerance. If you have any of these symptoms, seek an evaluation promptly.

Causes of hypertension:

Blood pressure has a natural variation – it lowers during sleep and rises on awakening. It also rises in response to excitement, anxiety and physical activity. Modern lifestyle factors are responsible for a growing burden of hypertension such as physical inactivity, salt-rich diets with processed and fatty foods, alcohol and tobacco use.

Types of hypertension:

High blood pressure that has no known cause is termed primary hypertension (or essential hypertension). This is more common than secondary hypertension, which has an identified cause such as chronic kidney disease. Primary hypertension is affected by environmental factors, including the lifestyle. Causes of secondary hypertension include renovascular disease (narrowing or blockage of the renal arteries or veins that take blood to and from the kidneys), adrenal gland diseases (the adrenal glands are small glands located on top of each kidney.

They produce hormones that you can't live without, including sex hormones and cortisol. Cortisol helps you respond to stress and has many other important functions. With adrenal gland disorders, your glands make too much or not enough hormones), and endocrine diseases like hypothyroidism (overactive thyroid gland).

Complications of hypertension:

Hypertension is called the 'silent killer' as it is symptomless and causes damage silently. Long-term hypertension can lead to the following complications.

1. Atherosclerosis: a disease of the arteries caused by a buildup of plaque, or fatty material, on the inside walls of the blood vessels. Hypertension contributes to this buildup by putting added tress and force on the artery walls.

2. Heart Disease: Heart failure (the heart is not strong enough to pump blood adequately), ischemic heart disease (the heart tissue doesn't get enough blood), and hypertensive hypertrophic cardiomyopathy (thickened, abnormally functioning heart muscle) are all associated with high blood pressure. Heart disease is the most common cause of death in hypertensive patients.

3. Kidney Disease: Hypertension is the most common risk factor for chronic kidney disease (CKD) after diabetes. Hypertension can damage the blood vessels and filters in the kidneys, so that the kidneys cannot excrete waste properly.

4. Stroke: High blood pressure is the biggest risk factor for stroke, which is the second most frequent cause of death in the world.

5. Eye Disease: Hypertension can damage the very small blood vessels in the retina. Rupture of blood vessels in the eyes can lead to vision problems or blindness.

Treatment of hypertension:

Early detection and proper treatment of hypertension is the need of the hour. Treatment consists of two parts – lifestyle modifications and pharmacologic or drugs. Lifestyle changes are important for both treatment and prevention of high blood pressure, and they can be as effective as a drug treatment. Modifications of lifestyle can lower blood pressure and reduce the incidence of mortality or death from cardiovascular diseases (conditions caused by narrowed or blocked blood vessels).

The lifestyle measures that are recommended by experts and shown to reduce blood pressure are: salt restriction, moderation of alcohol consumption, adoption of DASH or Dietary Approaches to Stop Hypertension (high consumption of vegetables, fruits and low fat), weight reduction and maintaining it, regular physical exercise like brisk walking, jogging, cycling, swimming for 30 minutes a day and giving up smoking.

Doctors will prescribe medication alongside lifestyle measures to lower blood pressure in people with a level above 140 over 90, although lifestyle measures are usually pursued first. Different classes of drug are available for lowering blood pressure. The choice of drug depends on the individual and any other conditions they may have.

Hypertension and pregnancy:

It is important to talk to your doctor if you have high blood pressure and are planning a pregnancy. This is because high blood pressure can create problems during pregnancy to both mother and baby. Blood pressure can be treated during pregnancy, but only certain drugs can be used and your doctor knows which drugs are safe and which drugs should be avoided.

Diabetes and Hypertension:

People with diabetes are more likely to also have high blood pressure or hypertension. The frequency of hypertension (HTN) in diabetic population is almost twice as compared to non-diabetic general population. In India about 50% of diabetics have hypertension. Managing blood pressure will be a part of a person's overall diabetes care plan.

Simple steps to keep your blood pressure under control:

1. Keep close watch over your blood pressure and keeping them at a goal set by your doctor.

2. Change your lifestyle (controlling weight, regular physical exercise, quitting smoking, moderation of alcohol consumption, dietary salt restriction, decreased oil consumption and following a balanced and nutritious diet.

3. Never skip or discontinue or change the medicines without the advice of your physician.

4. Follow up with your physician regularly.