High blood pressure is a disorder in which the pressure in the arteries is too high. The medical term for blood pressure that remains high over time is “hypertension”.

High blood pressure is very common, especially in middle-aged and elderly people. Once it has developed it tends to last for life. High blood pressure puts a strain on the heart and circulatory system, which can ultimately cause damage to many parts of the body.

About blood pressure
Blood is pumped out of the heart into the blood vessels and around the body under a certain pressure. Blood pressure rises and falls with each heartbeat, and is recorded as two numbers written as one number above or in front the other (See figure below).

The top number is called the “systolic” blood pressure and is the pressure in the arteries when the heart contracts and pumps blood out.

The bottom number is called the “diastolic” blood pressure and is the pressure in the arteries when the heart relaxes and fills with blood.

Normal, abnormal, and borderline blood pressure readings are discussed in more detail here. What should your blood pressure be?

Blood pressure is affected by many different factors and may vary in the same person at different times (See box below).

Factors influencing blood pressure The size and condition of the arteries The volume of fluid in the body The amount of blood pumped by the heart How much salt is in the body The condition of the kidneys and nervous system Levels of various hormones (eg, adrenaline, aldosterone)

Factors that increase the likelihood of developing high blood pressure (risk factors) Being overweight or obese (defined as a body mass index over 25 kg/m2)* Eating too much salt Frequent, heavy alcohol use Lack of exercise Older age Having a parent or close relative with high blood pressure Being of African-Caribbean origin * Body mass index is calculated from dividing your weight in kilograms by the square of your height in meters. Test your BMI here

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