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What causes essential, or primary, high blood pressure?

When the cause of high blood pressure is unknown, doctors call it essential, or primary, high blood pressure. This is the most common type of high blood pressure. Certain lifestyle factors, such as being overweight and eating too much salt, or sodium, may contribute to this form of high blood pressure. Some research also suggests that the following inherited conditions may put you at greater risk for high blood pressure.

  • Family history. If someone in your family has high blood pressure, you are more likey to have it.
  • An abnormality in your angiotensin-renin-aldosterone system. This system affects many aspects of blood pressure, including how your blood vessels contract and the balance of sodium and water in your blood.
  • An abnormality in your sympathetic nervous system. This system controls your heart rate, blood pressure, and the diameter of your blood vessels.
  • Insulin resistance. High blood pressure may be associated with problems using insulin, a hormone needed to break down your glucose in the blood. People who have insulin resistance problems need more insulin to maintain a normal level of glucose in their blood. They are often overweight and at greater risk for type 2 diabetes. Both of these conditions are associated with high blood pressure.
  • Low levels of nitric oxide. The chemical nitric oxide is believed to keep the smooth muscles that line the blood vessels relaxed and flexible so that blood can flow easily through them. This helps keep blood pressure down. Nitric oxide may also help prevent blood from clotting. Low levels can lead to high blood pressure.
  • Low birth weight. Some research has shown a link between being a low-birth-weight baby and developing high blood pressure in childhood or in later life.