To help prevent blood pressure from dropping sharply after meals, eat small portions several times a day and limit high-carbohydrate foods such as potatoes, rice, pasta and bread. Your physician also might recommend drinking caffeinated coffee or tea with meals to temporarily raise blood pressure.

Most specialists consider blood pressure too low only if it causes symptoms. Some experts define low blood pressure as readings lower than 90 mm Hg systolic or 60 mm Hg diastolic. If either number is below that, your pressure is lower than normal.

Uncontrolled high blood pressure can lead to stroke by damaging and weakening your brain's blood vessels, causing them to narrow, rupture or leak. High blood pressure can also cause blood clots to form in the arteries leading to your brain, blocking blood flow and potentially causing a stroke.