mets Flashcards
Energy Consumption (Metabolic Rate)
The amount of energy consumed per unit time. Can be measured in Watts, but more commonly in Cal (Kcal)/hour. Practical to measure oxygen consumption and calculate aerobic energy production from that.
VO2
rate of oxygen consumption measured in L/min
VCO2
rate of carbon dioxide production measured in L/min
VE
Minute volume. Amount of air exhaled per minute, can be seen as amt of air passing through the lungs each minute
RER
Respiratory Exchange Ratio is the ratio of carbon dioxide production to oxygen consumption. RER = VCO2/VO2
RER of pure carb
1.0
RER of pure fat
0.73
RER of pure protein
0.55
RER at rest
0.86
Oxygen Pulse
Amount of oxygen carried in the blood/beat of the heart. Useful index of heart function.
What do you need to know how much oxygen is pumped from the heart with each beat?
CO and VO2
Extraction Fraction
Ratio of oxygen consumed to the amount of air moved through the lungs (VO2/VE). Tells you how efficiently you extract oxygen from the air you breathe.
High extraction fraction tells you what?
More efficient use of the air you breathe, says how well lungs are diffusing gases across the membrane.
T or F: We could not determine how effectively we diffuse gases when we measure lung volumes.
TRUE
One MET
Value of oxygen consumption/energy production at seated rest. All energy demands are measured relative to this value for the subject. Determine relative intensity (resting = 1 met, walking = 3 mets)
