Quantifying Energy Expenditure

Question 1

How is Total Energy Expenditure (TEE) calculated?

Answer 1

Total Energy Expenditure = Basal Metabolic Rate (BMR) + Dietary Induced Thermogenesis (DIT) + Energy Of Physical Activity Levels (PAL) + Others

TEE = BMR + DIT + PAL + Others

Question 2

Explain what Energy of Physical Activities includes

Answer 2

Anything outside of a basic functioning

Question 3

Explain what Dietary induced thermogenesis includes

Answer 3

The production of heart that occurs after eating which contributes to the body’s resting metabolic rate

Question 4

Explain what Basal Metabolic Rate includes

Answer 4

The number of calories you burn as your body performs basic (basal) life-sustaining function

Question 5

What is Basal Metabolic Rate (BMR) also referred to as?

Answer 5

Resting Energy Expenditure (REE)

Question 6

Stress is also a component of energy expenditure. What things are classed as stress?

Answer 6

Burns

Wounds

Infection

Question 7

How is Resting Energy Expenditure (REE) calculated?

Answer 7

REE is measured as physical and mental rest, laying down, after an overnight fast of at least 10 hours with no stimulants of vigorous activity in the past 24 hours.

Question 8

What type of calorimetry is used to measure Resting energy expenditure (REE)

Answer 8

Indirect Calorimetry

Question 9

How is Energy Balance Measured?

Answer 9

Energy Balance = Energy Intake - Energy Expenditure

Question 10

How is Energy Intake Measured?

Answer 10

Energy Intake = Energy Expenditure + Total Energy Stores

Question 11

When would Energy requirements increase?

Answer 11

Weight Gain

Growth

Pregnancy

Training

Illness and Disease

Question 12

When would Energy requirements decrease?

Answer 12

Weight Loss

Loss of appetite

Post-training

End of Life

Question 13

Name the 3 ways energy expenditure is measured

Answer 13

Direct Calorimetry

Indirect Calorimetry

Prediction Equation

Question 14

Rank the methods of energy expenditure based on accuracy from most accurate to least accurate

Answer 14

Direct Calorimetry

Indirect Calorimetry

Prediction Equation

Question 15

Rank the methods of energy expenditure based on complexity from most complex to least complex

Answer 15

Direct Calorimetry

Indirect Calorimetry

Prediction Equation

Question 16

Explain how direct calorimetry works

Answer 16

The subject is placed in an insulated box/room/chamber

The heat produced by the subject warms the area

Temperature increase in measured

In the chamber: Cold water in, air in (O2), air out (CO2), heated water out

Question 17

What does direct calorimetry measure and give limitations?

Answer 17

Heat production

But no indication of substrate utilization (fat, carbohydrate) during exercise

Question 18

Explain what indirect calorimetry is based upon

Answer 18

Based on the relationship between O2 uptake and CO2 production.

Question 19

What can indirect calorimetry be used for?

Answer 19

By measuring O2 uptake and CO2 production, we can calculate the energy expended = Respirometry

Question 20

Give the types of indirect calorimetry (gas collection)

Answer 20

Room Calorimetry (ventilated chamber)

Metabolic cart (mouthpiece, mask or hood)

Portable respirometry (Douglas bag, IMP, oxylog)

Doubly-labeled water

Question 21

Explain how indirect calorimetry works with a ventilated chamber

Answer 21

Air is drawn through the chamber at a measured rate

The concentration of O2 and CO2 is measured accurately in air entering and leaving the chamber

Temperature and pressure recorded

Uptake of O2 and production ofCO2 calculated

Estimated energy calculated using a formula

Question 22

What things do portable respirometry require?

Answer 22

System to collect inspired/ expired air

Measurement of volume

Analysis of O2 and CO2 concentration

Calculation

Question 23

Name 3 types of portable respirometry technology

Answer 23

MedGem

BodyGem

Ecal

Question 24

Explain the principle of doubly labeled water

Answer 24

Stable isotope given to subject 2H2 18O - Deuterium = 2H2 , Oxygen-28 = 18O

Both isotopes mix with a pool of body water

The rate of each isotope’s disappearance from the body is measured

18O is lost more quickly as two ‘escape routes’

The difference in the rate of loss used to calculate CO2 production

Cos = (0.5 x TBW) x (rate 2H loss - rate 18O loss)

Calculate energy expenditure from CO2 production

Question 25

Explain the method for using doubly labeled water to measure the energy expenditure of a subject

Answer 25

The subject drinks an accurate dose of doubly labeled water

Sample saliva or urine daily for 1-2 weeks

2H lost as water (urine/breath), 18O lost as water and CO2

Measure the rate of constants for the disappearance

Differrence = CO2 production

rC02 is used to calculate energy expenditure

Question 26

What are prediction equations based on

Answer 26

Body composition, age, sex, disease, injury

If the above factors, it can predict BMR (Basal metabolic rate) or REE (resting energy expenditure)

Large studies 100’s - 100’s subjects

Data collected and standard equations produced

Equations vary depending on the population

Question 27

Give the Harris-benedict equations used to calculate BMR for Male and Female and give units

Answer 27

BMR Male = (10 x weight) + (6.25 x height) - (5 x age) + 5

BMR Female = (10 x weight) + (6.25 x height) - (5 x age) -161

Weight = kg
Height = cm
Age = yrs
BMR = kcal

Question 28

How is PAL (Physical activity level) calculated?

Answer 28

BMR X an appropriate factor for the amount of activity that a person does

Question 29

Name the 4 categories of lifestyle and give the PAL level

Answer 29

Sedentary - 1.40 to 1.69

Moderately active - 1.70 - 1.99

Vigorously active - 2.00 - 2.40

Extremely active - greater than 2.40