1. Resting Metabolic Rate (RMR)
How Do You Measure
ENERGY EXPENDITURE?

2. Metabolic Rate in Various Conditions
Basal Metabolic Rate (BMR)
Minimum energy required to sustain life
(Measured when Waking State with No Food & No Movement)
Resting Metabolic Rate (RMR)
Combination of…
Basal Metabolism (waking state)
Sleeping Metabolism
Arousal Metabolism
Exercise Metabolic Rate
Metabolism during Exercise + RMR

3. How Do You Measure Metabolic Rate?
Substrate (CHO or Fat) + O2 + Energy (ATP)
   CO2 + H2O + Energy (ATP) + Heat
Method #2
INDIRECT CALORIMETRY
Method #1
DIRECT CALORIMETRY

4. Method #1 DIRECT CALORIMETRY
Total Energy from Metabolism...
~40%  ATP
~60%  Heat
So…
if you measure your body’s heat production, you can estimate energy production!

5. DIRECT CALORIMETRY How Does It Work?
Insulated Chamber
Heat Exchanger
Water flow in the heat exchanger
The difference in the temperature of water entering and leaving the chamber reflects the person’s heat production.

6. DIRECT CALORIMETRY Problems
Expensive
Not applicable in most activities
Highly impractical for large-scale studies
Very few pieces of equipment in nation
So…Method #2 

7. Method #2 INDIRECT CALORIMETRY
Complete Combustion of Food IS
Achieved at the Expense of O2 Molecules.
So…
if you measure your oxygen uptake,
you can estimate energy production!

8. INDIRECT CALORIMETRY How Does It Work?
Oxygen Uptake
= (VO2 IN) – (VO2 OUT)
O2 Inspired
O2 Expired

9. INDIRECT CALORIMETRY Haldane Transformation
Assumptions
Ambient Air
FIO2 = 20.93% =
FIN2 = 79.04% =
FICO2 = 0.03% ~ 0 (ignore it)
FIN2 + FIO2 = 1
FEN2 + FEO2 + FECO2 = 1
VI*FIN2 = VE*FEN2 (N2 is inert gas)

10. INDIRECT CALORIMETRY Haldane Transformation
VO2 = (VI*FIO2) – (VE*FEO2)
VI*FIN2 = VE*FEN2
VE*FEN2
FIN2
VE* [1 – (FECO2 + FEO2)]
1 – (FECO2 + FEO2)
0.7904
VI =
VI =
VO2 = VE
X – FEO2

11. Respiratory Quotient (RQ)
CO2 produced
O2 consumed
Each substrate has its own RQ value.
(carbohydrates (1.0) vs fatty acids (0.7)?)
RQ =
At the CELL

12. RQ for CHO and FAT Carbohydrate (Glucose): Fat (Palmitic Acid):
C6H12O6 + 6O2  6CO2 + 6H2O + Energy
RQ = 6CO2 / 6O2 = 1.00
Fat (Palmitic Acid):
C16H32O2 + 23O2  16CO2 + 16H2O + Energy
RQ = 16CO2 / 23O2 = 0.70

13. What about Protein?
Protein is metabolized as either fat or carbohydrate and is therefore difficult to separate from the other two
Protein consumption is a small percentage of total metabolism during normal conditions and can be ignored

14. Respiratory Exchange Ratio (RER)
CO2 produced
O2 consumed
Actual gas exchange (RER) at the lungs can be greater or less than the RQ at the cell. It can range from slightly below 0.7 all the way to around 1.5 (lots of non-metabolic CO2)
(hyperventilation vs hypoventilation?)
RER =
At the LUNGS

15. How Do You Use RQ or RER? Assuming RQ = RER, you can estimate
the energy produced per liter of O2.
e.g.
RQ = 0.85  4.86 kcal/LO2
(Utilizing 50.7% CHO & 49.3% Fat)
 Table 4.4

16. Comparing RMR Absolute Oxygen Uptake (in LO2/min)
more muscle mass
 higher absolute VO2
Not able to compare
300 lbs football player and 130 lbs X-country runner
Relative Oxygen Uptake (in mlO2/kg/min)
Eliminates some of the differences in muscle mass by using body mass (body composition is unaccounted for)

17. Metabolic Equivalent (MET)
A MET is defined as a multiple of the Resting Metabolic Rate.
e.g.
If RMR (1 MET) = 3.6 mlO2/kg/min,
Work requires 7.2 mlO2/kg/min of O2 uptake = 2 METS
(# of METS in different activities?)

18. STPD Correction Factor
Volume of Gas expressed under Standard Conditions of
Temperature (273K or 0°C)
Pressure (760 mmHg or 1 atm)
Dry (no water vapor)
273K PBAR – PH2O
273K + TA (in °C) mmHg
(hot, wet condition vs cold, dry condition?)
STPDCF = X