BMI, or Body Mass Indicator, is a tool used to evaluate the amount of body fat that a particular individual is carrying. The number is based on a person’s weight for his or her height.
A formula is used to make a calculation to come up with the BMI number.
The first step is to take the individual’s weight in kilograms and divide it by his or her height in meters squared.
BMI and heart health are connected. The numbers are used as a way to calculate an individual’s risk of heart disease, high blood pressure and diabetes.
BMI Numbers and What they Mean
- A BMI of 18.5 or less is an indication the individual is underweight.
- A “normal” BMI is between 18.5 and 24.9.
- A BMI of between 25-30 is in the overweight range.
- An individual with a BMI of 31-39 is obese, and when this number reaches 40 or higher, it’s an indication of extreme obesity.
These numbers are not written in stone, however. It’s possible for a person who is very well muscled to have a BMI that doesn’t reflect his or her true level of fitness. The calculation is based on weight for height, and doesn’t take the fact that muscle weighs more than fat into the equation.
You will find a BMI calculator and a chart on the National Heart Lung and Blood Institute web site.
Waist to Hip Ratio for Calculating Body Fat
Along with BMI, another way to help calculate the risk of heart disease is to look at the person’s waist measurement. Belly fat and heart disease are linked, since carrying excess weight in the abdominal region can lead to hardening of the arteries, or atherosclerosis.
Atherosclerosis is a medical condition where plaque builds up in the arteries. Plaque is made up of cholesterol and fat, as well as other substances. It attaches to the interior walls of the arteries supplying the heart. Over time, the arteries become less flexible and the buildup of plaque means the arteries become narrow. The artery may become fully blocked or a piece of plaque can break off and become lodged in a more narrow blood vessel, triggering a heart attack.
To calculate the level of risk for heart disease from belly fat, simply take a tape measure and measure the hips at their widest part. The measure the waist at its smallest part. This is usually directly above the belly button.
Divide the waist measurement by the number of the hip measurement. For women, this number should be 0.85 or less. A healthy number for men is a bit higher; 0.9 or less is an indication of a healthy waist to hip ratio for heart health.