The force of the contraction of the heart can also affect blood pressure. In most people who have high blood pressure, the cause is unknown. In this case, high blood pressure is called primary, or essential, hypertension. Often, a person will have high blood pressure without any symptoms. The main sign of high blood pressure is an elevated systolic or diastolic blood pressure.
Blood pressure tends to rise with stress or exercise.
It should return to normal when the person is at rest. This means that the cause is unknown. The American Heart Association has identified both controllable and noncontrollable risk factors for high blood pressure. Uncontrollable risk factors for high blood pressure include age, heredity, and race. In men, high blood pressure occurs most often between 35 and 50 years of age.