BMI

Question 1

What is BMI?

Answer 1

BMI is used to measure body fat & to determine the overall fitness of a person, indicating the risk of them developing a disease. A change in BMI can tell us if a persons health is improving or deteriorating.
It is used to assess whether an individual is in normal range.

Question 2

How do you calculate BMI?

Answer 2

BMI= Weight (Kg)/Height (m)

Question 3

What are the thresholds for BMI categories?

Answer 3

18.5 & under is underweight
18.5-24.9 is healthy weight
25-29.9 is overweight
30-39.9 is obese
40+ is morbidly obese

Question 4

What are the clinical implications of BMI?

Answer 4

Those who are overweight are more likely to suffer from chronic disease e.g., type 2 diabetes
Those with excess fat around the abdomen tend to be more at risk
Patients who carry excess weight are more likely to suffer from sleep apneas
Patients with low BMI have a poorer prognosis than patients with weight in the normal range or overweight

Question 5

How to get correct measurements when calculating BMI?

Answer 5

Remove shoes
Remove outer clothes
Remove hats/hairclips
Empty pockets
Remove wearable medical devices if it is safe to do so
(make a note of it if it cannot be removed)

Question 6

What are the alternatives to standing height?

Answer 6

Demi span
Ulna length
full arm span

Question 7

Describe and explain demi span in calculating BMI

Answer 7

The arm is measured with palm facing forward
Measurement made from base of the ring finger to stretch notch.
This value x 1.35 for females calculates Height in cm
This value x 1.4 for males calculates height in cm

Question 8

Describe & explain ulna length in calculating BMI

Answer 8

This is measured with the arm bent across the chest
, palm flat on the chest, and fingers pointing to the opposite shoulders.
The length of the elbow to the midpoint of the prominent bone in the wrist is measured.
see table for height in males & females

Question 9

How do you take weight measurements during BMI?

Answer 9

• Ask the patient to remove outer clothing
• Ask the patient to take off shoes
• Make sure pockets are emptied
• Make sure the patient is able to get on the scales and stand unsupported
• allow measurements to stabilize
• record weight & allow the patient to step off scales
• clean the scales after use

Question 10

Describe and explain how to perform standing height when calculating BMI

Answer 10

Always use a patient’s current height
Use this method if the patient can stand
Height recorded in Meters
Position person with:
- feet together
- feet flat on the ground
- heels touching the back of the instrument
-straight legs
- butt against wall
- arms loose by side
- scapula touching wall

Question 11

Describe and explain how to perform full arm span when calculating BMI

Answer 11

It measures from fingertip to fingertip, mark the wall & measure distance between.
standing height can be calculated by dividing your value by 1.03 for males & 1.01 for females