The National Heart, Lung and Blood Institute reports that heart disease is the No. 1 killer of men and women in the United States. Each year, more than a million Americans have heart attacks, and about half a million people die from heart disease, according to the National Institutes of Health.

High blood cholesterol is one of the major risk factors for heart disease. The higher your blood cholesterol level, the greater your risks for developing heart disease or having a heart attack.

Your age, gender and genetic makeup can affect your blood cholesterol levels, but you have no control over those factors. Here are a few variables you can control to reduce your blood cholesterol:

Diet. Reducing the amount of saturated fat and cholesterol in your diet helps lower your blood cholesterol level.

Weight. Being overweight is a risk factor for heart disease. It also tends to increase your cholesterol. Losing weight can help lower your LDL (bad) cholesterol, and total cholesterol levels, as well as raise your HDL (good) cholesterol, and lower your triglyceride levels.

Physical activity. Physical inactivity is a risk factor for heart disease. Regular physical activity can help lower LDL cholesterol and raise HDL cholesterol levels. It also helps you lose weight. You should try to be physically active for 30 minutes most days.

For more information on blood cholesterol, visit http://www.nhlbi.nih.gov/.