Med-Fit Tech Assistant
Medical-Fitness Assessment - Learning Module #6
Anthropometrics
Part B
Part B: Calculating BMI & WHtR
Learning Objectives:
Learning Objectives:
- Correctly determine Body Mass Index (BMI)
- Correctly calculate Waist:Height Ratio (WHtR)
1. Body Mass Index
Body Mass Index (BMI) is a calculated value that allows direct comparison among people of differing height and weight. The BMI Chart below is useful to determine a client's BMI and healthy weight range without having to calculate the BMI directly.
- First, find the client's Height in the left-hand column. Example: Client is 5' 8" and 205 lbs.
- Then, find the client's approximate Weight in the horizontal row of the client's height. Example: 205 pounds = 203 pounds.
- Finally, find the client's BMI at the top of the column of the client's approximate weight. Example: BMI = 31
- Note the Category of the client's BMI, but be cognizant that it may need to be adjusted by the client's WHtR.
- As you gain experience using the chart, you will become more proficient at estimating the client's precise BMI to the first decimal. On the chart, a weight of 203 = a BMI of 31 and 210 = 32, so the client's weight of 205 would be a BMI of about 31.2.
- BMI is recorded as a number rounded to the first decimal point and without units (no inches or pounds).
If the client's Height and/or approximate Weight does not appear on the chart above, use the formula below to calculate BMI.
(Wt in pounds / Ht x Ht in inches) x 703 = BMI
Or, you may install and use a free BMI Calculator App on your phone. There are several excellent versions available.
2. Waist:Height Ratio
A person's Waist-to-Height Ratio (WHtR or WHR but not to be confused with Waist:Hip Ratio) is defined as Waist Circumference divided by Height, both measured in the same units (inches). It is used as a predictor of obesity-related cardiovascular and other chronic diseases. The WHtR is a measure of the distribution of body fat. Higher values of WHtR are correlated with abdominal obesity and indicate higher health risks. A "boundary" value of 0.5 or more (one-half or more of the person's height) indicates increased risk.
Waist Circumference (inches) .
-------------------------------------------- = WHtR
Height (inches) .
-------------------------------------------- = WHtR
Height (inches) .
- Use the Calculator App on your phone to calculate the client's WHtR.
- Record the WHtR as a number to the second decimal point without units. Example: 32 / 68 = 0.47