You know that high blood pressure and high cholesterol levels raise your risk of heart disease. But did you know that these two conditions often coexist, and that having both conditions can raise your risks of heart attack, stroke and other cardiovascular problems much more than either one alone?

Doctors have long said that people with cholesterol levels of 240 milligrams/deciliter or higher have about twice the risk of heart disease as people with total cholesterol of less than 200 mg/dL. A French study of about 200,000 men and women published in the European Heart Journal found that even borderline levels of total cholesterol (200 to 239 mg/dL) increase cardiovascular risks 3 to 4 times when combined with a systolic (top number) blood pressure of 130 to 139,, which falls in the category known as prehypertension.

A 2009 Cleveland Clinic study of people with coronary heart disease showed that those with very low levels(70 mg/dL or less) of low-density lipoproteins (LDL, or “bad” cholesterol) and normal systolic blood pressure (120 or less) had the slowest disease progression and were most likely to show improvement in their atherosclerosis (build up in the arteries). However, those with LDL levels above 70 did not show improvements in disease progression, even when their blood pressure was normal.

The good news? Ongoing research continues to find that maintaining normal blood pressure and cholesterol levels could prevent about half of all heart attacks and strokes. Bringing your levels into optimal ranges may reduce your risk for these life-threatening events by more than 80 percent.