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Lab 6: Measurement of Oxygen Uptake and Energy Expenditure

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Title: Lab 6: Measurement of Oxygen Uptake and Energy Expenditure


1
Lab 6 Measurement of Oxygen Uptake and Energy
Expenditure
2
Objectives
  • Understand the meaning and derivation of the
    oxygen uptake measurement and measurement of
    energy expenditure.
  • Perform techniques to measure oxygen uptake (O2),
    carbon dioxide production (CO2), and RER.
  • Calculate energy expenditure during exercise.

3
Aerobic Metabolism
O2
CO2
AIR
LUNGS
CO2
V/Q Lungs
O2
Pulmonary Circulation
Use O2, produce CO2 ATP from CHO, Fats
Heart
Muscle/Tissues
4
VO2 Fick Relationship
  • VO2 (ml/min) Q(L/min) AVDO2
  • Expanded HR SV 1.34 Hb (SaO2 -
    SvO2)
  • SV L blood/bt Hb g Hb/100 ml blood
  • 1.34 ml O2/gm Hb Saturations in decimal
    equivalent of
  • Affects of Heart Disease? Altitude? Lung
    Disease? Training?

5
Uses
  • Energy expenditure, efficiency, VO2max index of
    fitness, Time course of VO2 in response to work
  • Steady state concept

6
Important variables for measurement of VO2
  • VE or VI, FeO2, FIO2, FI CO 2, FeCO2
  • Assumption N2 not produced or used by body
    during exercise

7
Convert gas volumes to STPD from ATPS (CCJ Lab
Manual p. 60)
  • Standard Temperature Pressure Dry
  • Temperature 0 degrees Celsius
  • Pressure 760 mmHg (sea level)
  • Dry 0 humidity
  • Equation 1 
  • VSTPD VATPS (Pb - PH2O) /760 273/(oC
    273)
  •   Note PH2O under saturated conditions is
    temperature dependent (CCJ, p. 60).
  •   Ambient PH2O is obtained as
  •  Equation 2
  •   Ambient PH2O Saturated PH2O Relative
    Humidity/100

8
VO2 Consumption is volume O2 inhaled - volume O2
exhaled
  • Equation 3
  • VO2 (VI FIO2) - (VE FeO2)
  • NOTE VI ? VE unless 100 Carbohydrate oxidized
  • Remember C6H12O6 6O2 6H2O 6CO2
  • Therefore CO2 / O2 1

9
  • Haldane Transformation Allows us to calculate
    either VI or VE if only one is known. Based on
    fact N2 is not used or given off by body.
  • ? N2 in N2 out
  • or
  • Equation 4
  • VI FI N2 VE FeN2
  •  
  • Assume FIN2 1 - FIO2 - FICO2
  • FEN2 1 - FEO2 - FECO2
  •  
  • Standard air values FIO2 .2093
  • FICO2 .0003
  • FIN2 .7904

10
Hadane Transformation (cont)
  • Rearrange and combine 
  • Equation 5
  • VI VE (FeN2 / FI N2) or VE VI (FI N2 /
    FeN2) 
  •  
  • Substitute into VO2 equation if we measure VE
    gives
  • Equation 6
  • VO2 VE (FeN2 / FI N2) FIO2 - (VE
    FEO2)
  • _________VI __________ - __VE ___

11
VCO2 Production is volume CO 2 exhaled - volume
CO 2 inhaled
  • Equation 7
  • VCO2 (VE FECO2) - (VI FICO2)
  •  
  • Applying Haldane Transformation
  • Equation 8
  • VCO2 VE FECO2 - VE (FeN2 / FI N2)
    FICO2
  • ___ VE __ -__________ VI __________
  •  

12
Respiratory Exchange Ratio
  • Caloric equivalents as function of fuels consumed
    (CCJ, Table 6.1, p 62)
  • Equation 9
  • RER VCO2 /VO2

13
Examples of caloric equivalents and fuels
consumed
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