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Heart Smart Living
Heart Smart Living

Cardiologist, author, and heart health expert Dr. Sarah Samaan offers advice on how to live a heart smart life.

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Making Sense of the Body Mass Index

Different ways of measuring obesity.

The Robert Wood Johnson Foundation and the Trust for America’s Health recently released their 2011 report, “F as in Fat: How Obesity Threatens America’s Future.” The most telling statistic is the finding that 12 states now have obesity levels over 30 percent. Four years ago, only one state met that criterion.

There are a number of different ways to measure obesity. One involves measurements using calipers to evaluate fat thickness of various parts of the body; another uses bioimpedance, in which an electrical current is passed through the body to measure body fat and muscle mass. Even more specific is a technique in which the X-ray beams are used to measure fat tissue. However, the simplest and cheapest way to estimate body fat is to use a table that plots height against weight. This gives us our body mass index.

The National Heart Lung and Blood Institute offers a simple BMI calculator on their website. For most people, a BMI under 24 is ideal, whereas a BMI of 30 or greater defines obesity. People who fall in the middle are considered overweight. Obesity is associated with a higher likelihood of diabetes, heart disease, arthritis, lung disease, cancer, and even dementia. Obesity is also associated with much higher medical costs and a greater likelihood of serious disability.

Certainly, the BMI can misclassify some people. Typically, highly athletic types who carry a much greater amount of muscle mass than the rest of us. If you find yourself in the high BMI zone, and you’re not an athlete, check in with your doctor to be sure that you have not already developed complications of obesity. Then get help so you can lose weight safely, chart out an exercise plan, and live your life to its fullest.

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Tags: Risk Factors for Heart Disease , Weight and Heart Health

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About the Author


Dr. Samaan is an acclaimed cardiologist, writer, and heart health educator.