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Body mass index

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Illustrations

Calculating body frame size
Calculating body frame size

Alternative Names    Return to top

BMI

Information    Return to top

A good way to assess your weight is to calculate your body mass index (BMI). Your BMI estimates whether you are at a healthy weight. Being overweight puts strain on your heart and can lead to serious health problems. These problems include type 2 diabetes, heart disease, high blood pressure, sleep apnea, varicose veins, and other chronic conditions. More than 300,000 lives could be saved in the United States each year if everyone maintained a healthy weight!

HOW TO DETERMINE YOUR BMI

Your BMI estimates how much you should weigh, based on your height. Here are the steps to calculate it:

For example, a woman who weighs 270 pounds and is 68 inches tall has a BMI of 41.0.

Use the chart below to see what category you fall into, and whether you need to be concerned about your weight.

BMICATEGORY
Below 18.5Underweight
18.5 - 24.9Healthy
25.0 - 29.9Overweight
30.0 - 39.9Obese
Over 40Morbidly obese

BMI is not always an accurate way to determine whether you need to lose weight. Here are some exceptions:

Doctors use a few different methods to determine whether you are overweight. Your doctor may also take your waist circumference and your waist-to-hip ratio into consideration.

In addition, a lot of other factors influence your health. These include diet, physical activity, smoking, blood pressure, cholesterol levels, and blood sugar levels.

While the exact degree to which increasing BMI levels have a bad effect on human health is unclear, most experts conclude that a BMI greater than 30 (obesity) is unhealthy. Exercise, whatever your BMI, can help reduce your risk of cardiovascular disease and diabetes. Remember to always ask your doctor before starting an exercise program.

Update Date: 7/21/2006

Updated by: Benjamin W. Van Voorhees, MD, MPH, Assistant Professor of Medicine and Pediatrics, The University of Chicago, Chicago, IL. Review provided by VeriMed Healthcare Network.

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