Hypertension, or high blood pressure, refers to the pressure of blood against your artery walls. Over time, high blood pressure can cause blood vessel damage that leads to heart disease, kidney disease, stroke, and other problems. Hypertension is sometimes called the silent killer because it produces no symptoms and can go unnoticed — and untreated — for years.According to the Centers for Disease Control and PreventionTrusted Source (CDC), an estimated 75 million Americans have high blood pressure. Many risk factors for high blood pressure are out of your control, such as age, family history, gender, and race. But there are also factors you can control, such as exercise and diet. A diet that can help control blood pressure is rich in potassium, magnesium, and fiber and lower in sodium.