Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled gage pressure) is the pressure relative to the local atmospheric or ambient pressure. Various units are used to express pressure.
A BMI of 25 to 29.9 indicates a person is overweight. A person with a BMI of 30 or higher is considered obese. Like the weight-to-height table, BMI does not show the difference between excess fat and muscle. BMI, however, is closely associated with measures of body fat. It also predicts the development of health problems related to excess weight.
Research on obesity has shown that a calculation called BMI can be an accurate measure of body fatness. BMI stands for body mass index. While BMI does not measure body fat directly, it corresponds pretty closely to direct measures of body fat. Therefore, BMI can be considered an alternative for direct measures of body fat. BMI is determined by a person's height and weight. Because the BMI calculation requires only height and weight, it is inexpensive and easy to use. BMI is used as a method of screening for weight categories that may lead to health problems (see Health Effects of Obesity).