High blood pressure is more common with age. In addition, high blood pressure is more common in blacks than in whites. More men than women have high blood pressure in young adulthood and early middle age, but rates are about equal for ages 55 to 64. Rates for women surpass those for men at age 65 and older. Blood pressure is determined by the amount of blood your heart pumps and the resistance to blood flow in the arteries.
Small arteries limit blood flow.
Your blood pressure normally varies during the day. It rises during activity. It decreases with rest. Why it reaches or exceeds this level is not always known. In fact, a specific disease or cause is identified in fewer than 1 case in 20.