Measurement of energy expenditure

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(No Transcript)
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Units of Energy

• What are the SI units for Energy?
• What other units is Heat Energy often reported
  in?
• How would you convert units in 1 to units in 2?
• What is a MET?

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Calorimetry
Direct
Indirect
Calorimeter (Bomb)
Closed circuit
Open circuit
Respiration chamber
Expired gas CO2/N2 excretion Labelled water
(Bischoff Voit, 1860)
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Direct Calorimetry
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Caloric equivalence for O2 macronutrients
E.G. If the muscles were only using glucose and
the body were consuming 3L of O2 per minute,
then the rate of heat energy production 15.15
kcal.min-1
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Respiratory Quotient
Glucose
C6H12O6 6O2 6CO2 6H2O
38 ATP
RQ for CHO VCO2/VO2 6CO2/6O2 1.0
Palmitic Acid
C16H32O2 23O2 16CO2
16H2O 129 ATP
RQ for FAT VCO2/VO2 16CO2/23O2 0.70
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Caloric equivalence of RER
E.G. If the muscles were only using glucose and
the body were consuming 3L of O2 per minute,
then the rate of heat energy production 15.15
kcal.min-1
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RQ or RER

• Ratio of CO2 to O2 - reflects energy contribution
  - traditionally called RQ
• RER also reflects energy contribution - but
  conditions of production are different

RQ
RER
Respiratory Quotient
Respiratory Exchange Ratio
Cellular respiration
Ventilated air
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Failure of assumptions between RQ RER

• Metabolic acidosis
• Non-steady state conditions
• Hyperventilation
• Excess post-exercise VO2
• Prolonged Exercise

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Energy Expenditure (kcal/min) VO2 (L/min) x
kcal equivalent (kcal/L) _________________________
______ If exercise was performed for 30 min. with
the resulting data, VO2 2.2 L/min VCO2 2.1
L/min, what was the energy expenditure in KJ?
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Standard Temperature and Pressure Dry - STPD
Charles Law
Boyles Law
Temperature (C)
Pressure (mm Hg)
Volume (l)
Volume (l)
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Suggested Reading

• Wilmore and Costill (1999). Exercise Physiology
  (Chpt.4)
• Robergs and Roberts (2000). Exercise Physiology
  (Chpt. 4) Appendix D
• Powers and Howley (1997). Exercise Physiology
  (Chpt 6) Appendix A
• Foss and Keteyian (1998). Foxs Physiological
  basis for sport and exercise (Chpt. 4) Appendix
  D