Assessment of energy expenditure I

Question 1

What are the three overall components of energy expenditure?

Answer 1

Basal metabolic rate, DIT (dietary induced thermogenesis)/TEF (thermic effect of feeding) and physical activity

Question 2

What % of energy expenditure does basal metabolic rate account for?

Answer 2

65-75%

Question 3

What % of energy expenditure does DIT/TEF account for?

Answer 3

10%

Question 4

What % of energy expenditure does physical activity account for?

Answer 4

15-30%

Question 5

What can dictate BMR?

Answer 5

Mass/size

Question 6

What does Brodys mouse to elephant curve show?

Answer 6

There is a strong and predictable relationship between body mass and metabolic rate (between different organisms)

Question 7

What does direct calorimetry rely on?

Answer 7

The fact that the total heat loss is equal to the rate of energy utilisation when the body temp is constant

Question 8

How can direct calorimetry be measured?

Answer 8

Put an animal inside a chamber and surround the chamber with a water jacket. Measure the change in temperature of the water

Question 9

What are some problems with direct calorimetry?

Answer 9

Can’t monitor rapid changes, can only measure resting situations, cant account for friction

Question 10

What problem regarding substrate use is there with direct calorimetry?

Answer 10

Can’t determine which fuel is being used at any one time, only determine metabolic rate

Question 11

What is one alternative to direct calorimetry?

Answer 11

Measuring gas exchange during a period of time

Question 12

Why is measuring gas exchange a viable method for assessing energy expenditure?

Answer 12

Oxygen is used as a substrate for metabolism while carbon dioxide is produced

Question 13

What kind of calorimetry is using gas exchange to measure energy expenditure?

Answer 13

Indirect calorimetry

Question 14

What is used to do indirect calorimetry?

Answer 14

Douglas bags

Question 15

Which component of energy expenditure is typically measured using indirect calorimetry?

Answer 15

basal metabolic rate

Question 16

What do the Schofield and Harris-Benedict equations calculate?

Answer 16

Basal metabolic rate

Question 17

What is fed into the Schofield and Harris-Benedict equations?

Answer 17

Body weight, depending on sex

Question 18

How is the energy expenditure of exercise measured?

Answer 18

Exercising while doing indirect calorimetry

Question 19

When doing indirect calorimetry during exercise, when must the oxygen uptake be measured?

Answer 19

During steady state

Question 20

What is steady state of oxygen uptake during exercise?

Answer 20

A phase when the oxygen uptake is fairly constant

Question 21

Possible issues with using indirect calorimetry as an absolute measure of energy expenditure during exercise?

Answer 21

Someone may be “exercising” (i.e., walking or general movement) when not connected to the machine, so you’d get an underestimate

Question 22

Method of assessing energy expenditure over 24hrs?

Answer 22

Room calorimetry or whole-body calorimetry

Question 23

What kind of calorimetry are room calorimetry or whole-body calorimetry?

Answer 23

Indirect

Question 24

What does room calorimetry or whole-body calorimetry entail?

Answer 24

Subject being put into a sealed chamber for a few days, and the gas exchange is measured

Question 25

What is produced as a result of room calorimetry?

Answer 25

A graph of energy expenditure over 24 hrs

Question 26

Problem with room calorimetry?

Answer 26

Can’t measure representative behaviour

Question 27

Portable indirect calorimeters?

Answer 27

Worn on chest, used to measure gas exchange

Question 28

Issues with portable indirect calorimeters?

Answer 28

Expensive, can only wear for a few hours, inconveniant to wear