Dr. Mehmet Oz and Oprah Winfrey

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High cholesterol is a major risk factor of heart disease and, according to the FDA, the number one killer of men and women in America. There are two types of cholesterol: HDL and LDL. You want your HDL number to be high and your LDL number to be low.

The test: Cholesterol testing
When you should be tested: Once at age 20 to establish a baseline, then every five years after age 35
Why you should be tested: To prevent hardening of the arteries

Dr. Oz says an easy way to remember the difference between the two types of cholesterol is by thinking of HDL as "healthy cholesterol" and LDL as "lousy cholesterol."