Dr. Oz and Oprah discuss aging well.

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Question 7: Which of the following is most important to determine if you're aging well?
A) Blood pressure
B) Cholesterol
C) Your weight
D) Your heart rate

The correct answer is A.

Dr. Oz says that while many people worry more about weight and cholesterol, your blood pressure is actually the most important measure of your health.

Dr. Oz compares cholesterol's role in repairing arteries to the way plaster is used to fix a hole in a wall. But what causes the holes in your arteries in the first place? "Blood pressure … drives the holes in our arteries that we then have to fix with cholesterol. … So if we don't have the holes, we don't have to worry about it."

Dr. Oz says elevated blood pressure—the optimal number is 120 over 80—could take as much as 10 years off your life. If you have high blood pressure, Dr. Oz says it's important to follow all of your doctor's orders about salt intake, diet and drugs. "But of course, nothing's as good as exercise," he says. "That's really effective in getting blood pressure down."