Marjie Gilliam / Cox Newspapers

Q: Although I consider myself healthy, I took your advice and got a checkup before starting my new exercise program. I was surprised to hear that my BMI was higher than it should be, and that this might influence my health in other ways. I’m interested in knowing more. Can you help?

A: Body mass index, developed by the National Institute of Health, estimates percentage of body fat using height and weight. A BMI of 25 or higher is thought to increase risk of Type 2 diabetes, hypertension and cardiovascular disease. If your BMI is 25 or higher, take a look at lifestyle habits such as exercise and diet. Other important numbers to keep an eye on:

• Blood pressure: This is a measure of the pressure of the blood against the walls of the arteries. An optimal blood pressure reading for adults is below 120 over 80, while a reading of 140 over 90 or greater is considered elevated (high).

• Cholesterol levels: Cholesterol is a fatty substance that builds in arteries, leading to heart disease. Your doctor can check your HDL, LDL and triglycerides, and total cholesterol levels. In general, total cholesterol numbers should be below 200, with 240 considered high cholesterol, and anything between 200-239 considered borderline.

Triglycerides above 200 are considered high and may need treatment. An LDL above 130-159 is considered borderline high, 160-189 high, and 190 and above is considered very high.

• Waist circumference: One if the very best ways to keep track of body fat levels is by simply taking your waistline measurement on a regular basis. A waist size of 40 inches or more for men and 35 inches or more for women is considered high risk.

• Weight: I advise using the scale as only a general guideline, because it does not tell you anything about your actual health or body fat percentage. Fluid levels can also cause body weight to fluctuate; for some this can be as many as 3 to 5 pounds in a day.

That said, if you do decide to weigh, one method often used for calculating what is known as ideal body weight:

Men: Start with 106 pounds for 5 feet of height and add 6 pounds for every inch above this.

Women: Start with 100 pounds for 5 feet of height, plus 5 pounds for each additional inch.