High Blood Pressure: A Look at the Causes

Blood pressure is the force of blood against the walls of your arteries as it circulates in your body. High blood pressure occurs when blood vessels become narrow or stiff, forcing your heart to pump harder to push blood through your body. When the force of the blood against your artery walls becomes too high, you are said to have high blood pressure or hypertension.

How is blood pressure measured?

Blood pressure is measured as two numbers-a top number (called the systolic pressure) and a bottom number (called the diastolic pressure). A diagnosis of high blood pressure is not made on the basis of one high reading, but must be confirmed on two or more visits to your doctor or clinic. In general, for adults 18 and older, blood pressures that stay at 140/90 or more are considered high. However for people with diabetes or chronic kidney disease, a blood pressure of 130/80 or higher is considered high.

Blood pressure is measured with a blood pressure cuff around your upper arm. This cuff is pumped up and then let down while listening for the pulse sound. The systolic pressure is the pressure when the heart is beating. The diastolic blood pressure is the pressure when the heart is resting between beats.

What causes high blood pressure?

High blood pressure affects an estimated 50 million Americans. In most cases, the causes of high blood pressure are not known. However, some things may increase your risk of developing high blood pressure. These include:

  • Heredity: High blood pressure tends to run in families
  • Race: African Americans have high blood pressure more often and more severely than whites
  • Age: The tendency to develop high blood pressure increases as you age
  • Obesity: People who are overweight have a greater chance of developing high blood pressure
  • Lack of exercise: An inactive lifestyle may contribute to being overweight, which is a risk factor for high blood pressure
  • Excessive Alcohol use: Drinking excessive amounts of alcohol can increase blood pressure
  • Too much dietary salt: Heavy use of salt can increase blood pressure
  • Oral contraceptives: Women who take the pill have an increased chance of developing high blood pressure especially if they also smoke
  • Gender: Until age 45, high blood pressure is more common in men than women. Between ages 45 and 54 the risk is similar. After age 54, more women than men will have high blood pressure.
  • Other Diseases : Having chronic kidney disease increases your chance of developing high blood pressure

Can children get high blood pressure?

Yes, although high blood pressure is much less common in children. Regular blood pressure checkups should begin during childhood and continue throughout life.

Will I know if I have high blood pressure?

High blood pressure often causes no symptoms, even if severe. You can have high blood pressure for years without knowing it. That is why it is called a silent killer. The only way you can tell if your blood pressure is too high is to have it measured.

Is high blood pressure serious?

Yes. Uncontrolled high blood pressure can damage many organs in your body including your kidneys. It adds to the workload of your heart, which over time can enlarge and become weaker, and it increases the risk of strokes. Careful control of high blood pressure lowers the risk of developing these complications. That is why it is important to follow your doctor's advice concerning your treatment and to take all the medicines prescribed for you.

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©2013 National Kidney Foundation. All rights reserved. This material does not constitute medical advice. It is intended for informational purposes only. No one associated with the National Kidney Foundation will answer medical questions via e-mail. Please consult a physician for specific treatment recommendations.