DEAR DOCTOR K: I'm in my 20s. My doctor says I have prehypertension. How seriously do I need to take this?
DEAR READER: Quite seriously. High blood pressure, or hypertension, is a blood pressure of 140/90 mm Hg or higher. Only a few decades ago, blood pressure lower than that was considered normal -- or, at least, not worth worrying about. But during the last 20 years, multiple long-term studies have shown that people with blood pressures higher than 120/80 but lower than 140/90 have an increased risk of heart disease and stroke.