Two numbers, known as the systolic and diastolic readings measure blood pressure. It is believed that about 50 million Americans have hypertension.
Blood pressure is higher in men than in women and is generally higher in blacks than in whites.
Blood pressure increases with increasing age starting between the ages of 20-50. The amount of salt in the diet, particularly sodium, calcium and potassium Disruptions in one or more of the mechanisms listed above may cause hypertension. This is known as primary or essential hypertension. There are a number of different mechanisms that could go wrong to cause sustained high blood pressure, however, a specific cause has not been identified for primary hypertension. It is believed that genetics may be involved due to the fact that hypertension seems to run in the family.