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Science

Fitness and health

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Blood is under pressure in the arteries so that it reaches all parts of the body. Diet, exercise and other factors can affect the risk of heart disease developing.

Blood pressure

Arteries carry blood away from the heart. Blood in the arteries is under pressure because of the contractions of the heart muscles. This allows the blood to reach all parts of the body. You can see how the heart pumps the blood to the lungs and rest of the body by studying this animation:

Measuring blood pressure

Blood pressure is measured in millimetres of mercury, mmHg. There are two measurements:

  • systolic pressure - the higher measurement when the heart beats, pushing blood through the arteries, and
  • diastolic pressure - the lower measurement when the heart rests between beats

A young, fit person should have a blood pressure of about 120 over 70, which means their systolic pressure is 120 mmHg and their diastolic pressure 70 mmHg.

There are various factors that can increase blood pressure, including:

  • smoking
  • being overweight
  • drinking a lot of alcohol
  • stress.

A balanced diet and regular exercise can reduce high blood pressure.

Blood pressure - Higher tier

Extremes of blood pressure can create problems. High blood pressure can cause:

  • kidney damage
  • burst blood vessels
  • damage to the brain, including strokes.

Low blood pressure can cause dizziness, fainting and poor blood circulation.

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