Interdisciplinary Application

Body Mass Index

Health The Body Mass Index (BMI) is used by health care physicians to give a quick prediction of body fat. The BMI compares a ratio relating a patient's weight and height. BMI is a better indicator than weight alone. BMI is used to alert patients who may be at risk of some health problems. Patients with a high BMI may have a higher chance of developing hypertension, adult diabetes, or cardiovascular disease.

BMI is used because it is a simple calculation that applies to both men and women over the age of 18. However, children who are growing, and people with large amounts of muscle, such as competitive athletes, should not use BMI to estimate their body fat.

Most professionals consider BMI readings between 19.5 and 24.9 to be optimum.

Readings between 18 and 19.5 may indicate a form of mild starvation. Readings over 30 may indicate high body fat content. While these may be recommended scores, the risks of higher body fat may be offset by a strong cardiovascular system. Your doctor can give the best advice to your specific body fat content. The BMI test should be used as an indicator.

In Exercises 1-5, use the following information. A person's Body Mass Index M can be modeled by

h = 40√(0.45w/M)

where h is the height in inches and w is the weight in pounds.

1. Graph the model for a person who weighs 120 pounds.

2. Find the Body Mass Index of a patient who is 6 feet tall and weighs 170 pounds.

3. A person is 5 feet 5 inches tall and has a Body Mass Index reading of 25. Find the person's weight.

4 A physician suggests a person should have a Body Mass Index reading between 23 and 27. Find the two weights a person should try to stay between if he or she is 5 feet 9 inches tall.

5. Find the Body Mass Index readings of a person who is 6 feet 2 inches tall and weighed 210 pounds but now weighs 175 pounds.