You may notice a lot of trainers use a lot of technical and sometimes overly fancy words when they are talking to you about your health and fitness. While this makes us sound extremely intelligent (insert sarcasm here) I would rather put it in terms of exactly what it is and how it directly relates to your health. The topic today...Body Mass Index...or BMI for short.
In a nutshell, BMI uses a classification scale to determine whether an individual is of a normal weight, overweight, or obese...here is what the scale looks like:
Now that we have the scale how do we determine our BMI.....by using the following formula:
[weight (pounds) divided by/height (inches)squared] x 703
Using myself as an example, I am 160 pounds and 72 inches tall...when we plug this info into the formula we get
[160/5184] x 703 = BMI of ~22 which equates to normal for my weight and size
So when is it appropriate to use BMI calculations and when is it not?
BMI is the preferred body composition assessment for obese individuals but not so useful for athletes or individuals with a high percentage of lean muscle mass (more on that in a bit). Other methods (such as skinfold assessments) become inaccurate due to the size of the skinfold and lack of standardized formulas for obese adults.
So why is knowing your BMI important...to put it simply (and this does not apply to all individuals) the higher your BMI the more likely you are to have other risk factors applicable to your health such as high blood pressure or cholesterol. Hopefully, it is apparent why it is important to lower your BMI through diet and exercise sooner than later.
Although BMI is a useful tool for sedentary or obese individuals it does have its flaws when applying it toward athletes or those that are heavier and have a high amount of muscle. Say for example you have a 220 pound, 6-foot tall linebacker. Using the calculation above his BMI would come out to be ~30...which is borderline obesity. However, this individual may have 8% body fat which the BMI calculation does not account for. Obviously this linebacker it extremely fit and BMI in his case would not be useful.