body composition

Question 1

Whole body plethysmography (BOD POD)

Answer 1

uses Boyle's law
a chambered unit
2-compartment model assessment( fat mass and fat-free mass)
density= mass/volume
clothing and hydration dependent

Question 2

Bioelectrical Impedance analysis

Answer 2

use hand-hand, foot to foot, hand to foot electrode placement, and abdominal wall
Can have baseline DXA that can then be correlated with BIA

Question 3

Deuterium dilution

Answer 3

2 compartment to estimate Total Body Water, which is mainly in fat free mass
Give Deuterium, measure concentration of D20 in blood/saliva/urine, then calculate amount of TBW, then estimate % fat

Question 4

What % of fat free mass is water?

What % of muscle and body organs is water?

Answer 4

70%

75%

Question 5

What is bone mineral content made up of?

Answer 5

Calcium OH apatite ( Ca and PO4)

Question 6

What is the weight of bone mineral content

Answer 6

10 pounds or less

Question 7

what is the proportion of body fat in different common races

Answer 7

Hispanic>Caucasion>Black

Question 8

Hydrodensitometry uses Archimedes principle, requires what measurements

Answer 8

Body weight out of water, measure weight underwater after exhalation
2 compartment model
Muscle sinks, fat floats., so person with increased body fat will weight less under water compared to a patient with increased muscle, will have lower density.

Question 9

BIA measures the resistance of body tissues to an electrical current. Electrical current passes more easily through what? Assumes fat free mass has a constant proportion of water that is _____%

Answer 9

Passes more easily through water and muscle than fat.
Fat free mass 70% water
Need to avoid exercising, avoid Etoh and caffeine

Question 10

What are the components of total energy expenditure?

Answer 10

physical activity 15-30%
dietary thermogenesis 10%
resting metabolic rate 60-75%

Question 11

Where are mitochondrial uncoupling proteins, UCP 1 and UCP 3 found

Answer 11

UCP1 brown adipose tissue

UCP3 skeletal muscle, heart and brown adipose tissue

Question 12

Bioelectrical Impedance should not be used with 3

Answer 12

Pacemaker
high BMI
old age/disease states

Question 13

DEXA not good with

Answer 13

high BMI

*determining visceral vs subcu. adiposity

Question 14

Bod Pod(air displacement pleth.) 
good for

Answer 14

all ages including infants

NOT high BMI, discerning subcu vs visceral

Question 15

Dilution technique inaccurate with

Answer 15

infants

disease states

Question 16

MR is best for

Answer 16

determining specific fat distribution

Question 17

Exercise stress target HR

Answer 17

85% predicted maximal HR ( 220-age)

Question 18

MET on exercise stress test that predicts poor prognosis with major surgery, that predicts excellent prognosis

Answer 18

<4 METS

>13 METS

Question 19

What does lean body mass include (that fat-free mass doesn’t)

Answer 19

fat in organs,bone marrow and CNS