High Blood Pressure

Dr Thapelo Motshudi
15 June 2022
3 min read

What is high blood pressure?

Hypertension, commonly referred to as “high blood”, is a condition that involves many systems in the body, and it results in abnormally elevated blood pressure. Blood pressure is determined both by the amount of blood your heart pumps, and the amount of resistance to blood flow in your arteries. The more blood your heart pumps, and the narrower your arteries, the higher your blood pressure.  Blood pressure readings are measured in millimetres of mercury (mm Hg).

The readings have 2 numbers, and the first, or upper number, measures the pressure in your arteries when your heart beats. It is called systolic pressure. The second, or lower number, measures the pressure in your arteries between beats, and it’s called diastolic pressure.

According to the World Health Organization (WHO), about 46% of adults with hypertension are unaware that they have the condition. Also, it is estimated that less than half of adults (42%) with hypertension are diagnosed and treated.

What are normal and abnormal blood pressures?

  • Blood pressure is considered normal if it's below 120/80 mm Hg.
  • Elevated blood pressure is a systolic pressure ranging from 120 to 129 mm Hg, and a diastolic pressure below 80 mm Hg. Elevated blood pressure may also be called prehypertension, and it tends to get worse over time unless steps are taken to reduce it.
  • Stage 1 hypertension is a systolic pressure ranging from 130 to 139 mm Hg, or a diastolic pressure ranging from 80 to 89 mm Hg.
  • Stage 2 hypertension is a systolic pressure of 140 mm Hg or higher or a diastolic pressure of 90 mm Hg or higher.
  • Hypertensive crisis is a blood pressure measurement higher than 180/120 mm Hg, and it is an emergency that requires urgent medical care. If you get this result when you take your blood pressure at home, wait five minutes and retest. If your blood pressure is still this high, contact your nearest health facility immediately.

What is low blood pressure?

Low blood pressure, or hypotension, occurs when the systolic (upper number) pressure is less than 90 millimetres or the diastolic (lower number) pressure is lower than 60 mm Hg. However, for some people, this might still be normal. It is caused by dehydration and other medical conditions. Symptoms include dizziness, blurred vision, nausea, fatigue and fainting.

What causes hypertension?

Hypertension is classified as being primary (also called essential) or secondary. Primary hypertension has no identifiable cause, although the kidney is both the contributing and affected organ, and it tends to develop gradually over several years. Secondary hypertension has numerous causes, including kidney disease, adrenal gland tumors, thyroid problems, certain medications, and abuse of illegal drugs such as cocaine and amphetamines. Most people, over 80% or so, have primary hypertension.

What are the risk factors for hypertension?

There is a long list of risk factors, including those that can be changed, and those that cannot be changed. Factors that cannot be modified include age, race, sex, and genetics. By controlling the modifiable risks, one can mitigate the genetic factors, so hypertension might not progress rapidly to its dreaded conclusion. Some of the risk factors include:

  • Age - the risk of high blood pressure increases as you age. Until about age 64, high blood pressure is more common in men. Women are more likely to develop high blood pressure after age 65.
  • Family history - high blood pressure tends to run in families.
  • Being overweight or obese - The more you weigh, the more blood you need to supply oxygen and nutrients to your tissues. As the amount of blood flow through your blood vessels increases, so does the pressure on your artery walls.
  • Lack of physical activity also increases the risk of being overweight.
  • Smoking - not only does smoking or chewing tobacco immediately raise your blood pressure temporarily, but the chemicals in tobacco can damage the lining of your artery walls. This can cause your arteries to narrow and increase your risk of heart disease. Secondhand smoke can also increase your risk of heart disease.
  • Too much sodium in your diet can cause your body to retain fluid, which increases blood pressure.
  • Too little potassium in your diet.
  • Drinking too much alcohol - Over time, heavy drinking can damage your heart.
  • Stress.
  • Certain chronic conditions also may increase your risk of high blood pressure, including kidney disease, diabetes, and sleep apnea.

What are the symptoms and complications of hypertension?

Hypertension affects all bodily systems; therefore one can present with all manner of medical problems. These include persistent headaches; epistaxis or nosebleeds; heart failure; chest pains from decreased blood flow to the heart; progressive loss of vision; fainting spells and strokes; kidney failure; erectile dysfunction in men, especially when combined with diabetes; aneurysms; Trouble with memory or understanding dementia; and many other symptoms.

In the most extreme cases, it is discovered for the first time that someone has hypertension when they collapse and die from a massive stroke. Contrary to what some people believe, it is not possible to feel that your blood pressure is high, that is why hypertension is called the “silent killer”. Palpitations (heart beating too fast) are not proof that one has hypertension. The only way to know your blood pressure reading is to have it measured.

What happens after a high blood pressure reading?

Once your doctor has measured your BP and found it to be high, the doctor will repeat the measurements several times, and normally not on the same day, because one reading is usually not used to diagnose hypertension. After the diagnosis has been confirmed, the doctor will perform a full physical examination to look for signs of what is medically referred to as target organ damage, or signs of complications.

These signs are seen when organs like the eyes, kidneys or the heart are already demonstrating evidence of damage from chronic elevated blood pressure. Depending on the findings, further investigations can be requested, including blood tests; chest x-ray; ultrasound of the arteries of the neck; ultrasound of the heart; ultrasound of the kidneys and abdomen; scan of the brain; and ECG.

How is hypertension treated?

The first line of treatment includes modification of the lifestyle risk factors, and even after progressing to medication, these are still key to managing the condition. These include the following:

  • Eat a heart-healthy diet with less salt
  • Stop smoking
  • Employ stress reduction techniques
  • Regular physical activity
  • Lose weight if you're overweight or obese
  • Limit the amount of alcohol you take

Depending on the severity, extent of target organ damage, complications, and response to treatment, oral medication might be prescribed, sometimes going up to 3 or more different types of tablets at once.

Can hypertension be cured?

Removing the cause of the elevated blood pressure, if it is a known curable condition, can cure secondary hypertension. Primary hypertension, however, cannot be cured, but it can be well-controlled and treated, either with risk factor modification alone or in combination with medication, to the point where one lives a full and fruitful life without suffering the complications. So have your blood pressure measured regularly by your local health professional to avoid finding out after there has been organ damage already.

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The content in this communication is for information purposes only and is not intended to be detailed advice. You should seek the advice of your physician or a qualified healthcare provider with any questions you may have regarding a medical condition.


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