Body Mass IndexHip-To-Waist Ratio

12/3/2012SHMD 139

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Statistics

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Statistics

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Health Risks Associated with Being Overweight

• Coronary heart disease• Hypertension• Hypercholesterolemia• Diabetes

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Health Risks Associated with Being Overweight

There are also health risks associated with being too thin!• The body reacts to the lack of food by becoming extremely thin• developing brittle hair and nails• dry skin• constipation, diarrhea• reduced muscle mass, loss of menstrual cycle• swelling of joints• heart problems • osteoporosis• mental health issues • death

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Body Mass Index

• BMI: A measure of body composition using a height-weight formula

• BMI is used to give us an idea of whether the client is obese, and the

extent of their obesity

• Formula:

– Body mass index (BMI) = weight in kilograms divided by height in

meters squares

– BMI = kg

h2

– BMI unit of measurement: kg/m2

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BMI example

– A man weighs 86 kilograms, and is 1.89 meters tall.

Calculate his BMI.

– BMI = kg

h2

– BMI = 86

1.892

– BMI = 24.1 kg/m2

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BMI ClassificationCategory BMI (kg/m2)

Underweight < 17.5

Normal 17.5 – 24.9

Overweight 25 – 29.9

Obese class I 30 – 34.9

Obese class II 35 – 39.9

Obese class III > 40

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Implications of BMI

As BMI increases above

the range of ‘obese’, so

the risk increases for

cardiovascular

complications (including

hypertension & stroke),

cancer, diabetes etc.

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BMI Limitations

• BMI does not actually measure body

composition.

• It can be used as a quick measurement to check

if an individual is overweight, but it is inaccurate.

• BMI does not distinguish between fat and

muscle.

• Muscle is denser, thus heavier than fat.

• i.e. A person with a lot of muscle may be

inaccurately described as obese.

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HEIGHT• Stand with heels together

• Buttocks and upper back must be touching the wall

• Head must straight, eyes looking forward. Do not tilt the head up

or down.

• The subject must try make themselves as tall as possible without

lifting their heels or tilting their heads

• Place the head board flat on the subjects head, compressing the

hair as much as possible.

• Record to the nearest 0.5cm

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WEIGHT

• Check that the scale is reading zero, if it is not, set it back to zero

• The subject should be barefoot and have minimal clothing on. i.e.

Nothing in their pockets such as cellphones, keys etc., take off

heavy belts, jackets, & jewellery

• The subject should stand in the centre of the scale, with weight

evenly distributed on both feet

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Examples

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• Hip-to-waist ratio (HWR) is taken as an indicator of the health risks

associated with obesity, and in particular the risk of coronary heart disease.

Regional Fat Deposition

• Fat stored in the abdominal area is a greater risk factor for CHD because it

is closer to the heart and can easily mobilise into the blood stream and be

taken to the heart.

Hip-To-Waist Ratio

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Hip-To-Waist Ratio• Males store more fat centrally and have increased health risks

associated with body fatness.

Higher health risk Lower health risk

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Hip-To-Waist Ratio

• Hip-to-waist ratio = waist measurement in

centimetres divided by hip measurement in

centimetres.

• HWR = waist (cm) hip (cm)

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Hip-To-Waist Ratio Classification

Gender HWR Classification

Males > 1.0 High risk

0.90 – 0.99 Moderate risk

< 0.90 Low risk

Females >0.85 High risk

0.80 – 0.85 Moderate risk

< 0.80 Low risk

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Hip-To-Waist Ratio example

• A female has a waist measurement of 68cm, and a hip

measurement of 101cm. Calculate her HWR.

• HWR = waist (cm) hip (cm)

• HWR = 68 cm101cm

• HWR = 0.67

• Classification: Low risk

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Waist Measurement

• Taken at the level of the belly button, with the stomach

muscles relaxed and after normal expiration.

• The tape measure is put around the waist and a horizontal

reading is taken.

• Ensure the tape is level all the way around.

• Take the reading from the side, not the front; respect the

person’s personal space.

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Hip Measurement

• Is taken with the client standing up, with their feet

together.

• The measurement is taken at the widest circumference

around the hips.

• Ensure the tape is level all the way around.

• Take measurement from the side, respect their personal

space.

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Body Fat & Sports Performance

Jockey:

Average weight: 50.44kg

Average height: 1.57m

BMI: 20.46

Sumo Wrestler:

Average weight: 219kg

Average height: 1.91m

BMI: 60.03

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Body Fat & Sports Performance

• Excess body fat can negatively influence many types of sport

performance requiring jumping and running.

• High ratios of fat free mass to fat mass are generally positively

related to sport.

• Athletes are leaner than sedentary individuals – regardless of

gender.

• Extremely low fat mass in women can result in health problems

(Refer: “too thin”).

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Body Fat & Sports PerformanceSwimmer

Balletdancer

Rugby player

Volleyballplayer

Body builder

Sumo Wrestler

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Questions1. What do the following abbreviations stand for:

1. BMI 22. WHR 2

2. What is the unit of measurement for BMI? 13. What are the risks associated with being overweight? 44. List 8 risks associated with being underweight. 85. What is BMI; and what is it used for? 46. What is the calculation used for BMI? 27. A man weighs 76kg and is 1.71m tall. Calculate his BMI. 28. In tabular form, write down the categories and range of BMI. 129. What are the implications of a high BMI? 210. What are the limitations of BMI? 311. Write down the procedure for measuring height and weight. 10

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12. What is the WHR used for? 213. Differentiate between the ‘apple’ and ‘pear’ body shape, also explain which one

is of greater risk and why. 614. Which shape is generally associated with males, and which shape is generally

associated with females? 215. What is the formula for measuring WHR? 216. If a woman has a waist measurement of 72cm, and a hip measurement of

110cm, calculate her WHR. 217. Describe the procedure for measuring WHR. 818. How would BMI differ between a race horse jockey and a sumo wrestler, and

why? 619. How does the body composition of a ballet dancer differ from that of a body

builder? 4

Questions