Blood pressure is measured by the amount of blood your heart pumps and the degree of resistance to blood flow in your blood vessels. Your blood pressure rises with more blood flow and higher blood flow resistance (caused by narrower blood vessels) because your heart has to work much harder to pump blood out to the body.
High blood pressure (also called hypertension) is dangerous because the extra stress placed on your heart can lead to a heart attack, a stroke (when blood flow to the brain is cut off), and many other health problems. No one knows for sure what causes high blood pressure, but there are known risk factors. These include:
- not getting enough exercise
- drinking too much alchohol
- having too much sodium (salt) in your diet
- being overweight
- having family members with high blood pressure
High blood pressure can also affect the eyes. It's a known risk factor for:
It can also affect vision by leading to blocked veins and blocked arteries in the retina, which can cause permanent vision loss.