Assessment of energy expenditure II

Question 1

Portable indirect calorimeters?

Answer 1

Worn on chest, used to measure gas exchange

Question 1

Issues with portable indirect calorimeters?

Answer 1

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

Question 2

Best method of measuring energy expenditure outside a lab?

Answer 2

Doubly labelled water

Question 3

Error using doubly labelled water?

Answer 3

1-5%

Question 4

What does doubly labeled water use?

Answer 4

Heavy isotopes of hydrogen and oxygen

Question 5

How does doubly labelled water work?

Answer 5

When 2H and 18O are introduced into the body,. they mix with the normal H and O. The 18O is lost more rapidly than the 2H as it is lost in CO2 and H2O, compared to the 2H being lost in only H2O

Question 6

What is used to calculate CO2 production in doubly labelled water?

Answer 6

Difference in loss of 2H and 18O

Question 7

Limitations of carrying out DLW?

Answer 7

High equipment cost and specialised staff required

Question 8

Assumptions made when doing DLW?

Answer 8

RER of 0.8 or 0.85 is assumed

Question 9

Limitations of information gained from DLW?

Answer 9

No information on components of energy expenditure, only a total EE

Question 10

Issues with DLW for exercise physiologists>?

Answer 10

As it only gives a total, it is difficult to know the pattern of intensity (i.e. what exercises caused the most expenditure)

Question 11

What are activity diaries and recall questionnaires?

Answer 11

Patients self report activity that they have done
An activity score/MET value is attributed to each activity and used to estimate EE

Question 12

What is the compendium of physical activities?

Answer 12

Big book that has the energy expenditure expected from basically every exercise ever

Question 13

In the compendium of physical activities, what is one MET equivalent to?

Answer 13

One metabolic rate

Question 14

How is the compendium used?

Answer 14

Find the activity, and how long you did it for
Multiply the MET attributed to the activity by your BMR
Multiply it by the minutes that you did the activity for

Question 15

Issues with compendium of physical activities?

Answer 15

Takes a long time to account for every single thing that someone has done

Question 16

Issues with self reporting activity?

Answer 16

Exercise is subjective, people may forget, people may overreport to seem “better”

Question 17

What devices can be used to measure physical activity?

Answer 17

Pedometers and accelerometers

Question 18

Pros of using devices to measure physical activity?

Answer 18

Don’t rely on people remember things, more factual

Question 19

Issues with pedometers and accelerometers?

Answer 19

Only measures ambulatory activity (arm exercise may not be measured)

Question 20

Alternative to pedometers?

Answer 20

Heart rate monitors

Question 21

Pros of using heart rate monitors

Answer 21

Easy to wear

Question 22

Issues with using heart rate monitors?

Answer 22

Linear relationship between HR and EE is lost at low intensities, and other factors such as stress can influence HR

Question 22

What are multi-sensor physical activity monitors?

Answer 22

Devices that use multiple inputs –> heart rate, accelerometry etc to measure activity

Question 23

Pros of multi-sensor physical activity monitors?

Answer 23

Can cancel out each others weakness--> HR is a poor predictor of EE at low intensities but accelerometry is a good predictor of EE