Experts estimate that more than 700,000 Americans have a stroke each year, and the number is steadily increasing. Strokes interrupt blood flow to the brain, killing the cells by depriving them of oxygen. Dr. Sudha Seshadri and colleagues examined both the current blood pressure readings and records from prior decades of participants in the Framingham Heart Study. They found that a 20-point rise in systolic blood pressure when people are in their 60s raises their stroke risk by 50 percent after they reach age 70. A 20-point elevation during the 50s raises the risk 40 percent later on.
Blood pressure is read as systolic over diastolic.
A normal systolic reading is around 120. According to Dr. Ralph Sacco of Columbia-Presbyterian Medical Center in New York, the study is important because it illustrates the impact of this risk factor over a lifetime. Dr. Seshadri presented the findings February 10 at a meeting of the American Stroke Association and they were reported by the Associated Press.