Elevated BMI

Body mass index, or BMI, is a measurement that is used to determine if your weight is within a range considered healthy in comparison to your height. A high BMI is believed to increase your risk of diabetes, heart disease, cancer, high blood pressure and high cholesterol. A BMI of 25 or greater is considered overweight, and 30 or greater is considered obese, explains Northwestern Health Sciences University.

BMI Calculation

Body mass index can be calculated by multiplying your weight in pounds by 703, then taking that result and dividing it by your height in inches and then dividing that result by your height in inches again, according to the University of Maryland Medical Center.
Guidelines for interpreting BMI note that being underweight is equivalent to a BMI of less than18.5, a normal BMI is between 18.5 and 24.9, and an elevated BMI is equal to or greater than 25.

Considerations

The American College of Sports Medicine reports that BMI is an unreliable measure of muscular athletes, as determined by a team of researchers that studied high school football players, whose muscular body composition led to overstated BMI readings. Also, a BMI measurement does not take body fat percentage into consideration, and therefore does not identify those with a normal weight that have a higher percentage of body fat than is considered healthy.

Exceptions

According to the University of Maryland Medical Center, although BMI is an accepted way to measure healthy weight, it's not always an accurate way to determine the need for weight loss. Exceptions include elderly persons who may be protected from osteoporosis, or brittle bones, by a BMI between 25 to 27, athletes with a large muscle mass, and children, whose pediatricians should determine an appropriate weight. BMI in children and teens is classified differently than in adults, taking into account the normal differences in body fat between the sexes and differences at various ages.

Other Meaurements

Because BMI is an unreliable indicator of body fat percentage, BMI should be validated by other measurements. Measuring waist circumference is important because abdominal fat is a predictor of disease risk related to obesity. Assessment of your risk factors of other diseases associated with being overweight, such as lack of exercise and high blood pressure, is necessary, notes the Centers for Disease Control and Prevention. According to the University of Northwestern Health Sciences, measurement of body fat is a better measure of your health. Body fat can be measured with skinfold calipers and Bioelectrical Impedance (BEI). The best measure of body fat is underwater weighing.

Expert Insight

The American College of Sports Medicine, or ACSM, advises that in addition to BMI other measurements be made to assess risk of obesity-related disease. These measurements include HDL cholesterol, waist measurement, systolic and diastolic blood pressure, blood sugar and triglycerides. The ACSM reports that the most prevalent risk factor for obesity-related disease are low HDL cholesterol, or good cholesterol, followed by elevated blood sugar.
Individuals who are normal weight or overweight might have fat distribution that is abnormal or high body fat percentages that increase their risk of disease. An article in a 2010 issue of the "American Medical Association Journal of Ethics" recommends that additional steps be taken to determine these risks.