The newest guidelines call for having a fasting lipoprotein profile every five years starting when you're 20. The blood test measures total cholesterol—which should be less than 200 mg/dl (milligrams per deciliter)—and its Dr. Jekyll/Mr. Hyde components: good HDL, which protects your ticker, and demon LDL, a major cause of heart disease ("Happy" and "Lousy" are how one doctor teaches patients to remember which is which). To lower cholesterol, doctors usually recommend dietary changes (note that only foods with soluble fiber, like oats and beans, have been shown to help lower cholesterol; whole-wheat bread and bran muffins with insoluble fiber have not). There are also effective medications.