According to Mothernature.com, by the time Americans reach 55 years old, about 30 percent of Caucasian men and 20 percent of Caucasian women have blood pressure above the recommended level of 140. Generally the ratio of a healthy high blood pressure to heart rate is 140/90. About 50 percent of African-American men and 40 percent of African-American women of the same age were at risk for high blood pressure. About 50 percent of people with high blood pressure may not know it. Generally, doctors recommend getting your blood pressure checked every other year, more often if you have hypertension.