S1L3 Energy Expenditure Flashcards
What is a calorie and how is it measured?
= amount of energy needed to raise 1g of water by 1 degrees C.
use a Calorimeter –> Sample is oxidised, energy comes out as heat, water increases in temp by a certain no. of degrees. –> see how much energy released
What are the pros and cons of direct calorimetry?
+ direct measure of heat
+ accurate for steady state measures
- expensive
- slow to generate results
- few in operation
- no reflection of immediate exercise measures
what is RER and what are the values for glucose and palmitic acid?
RER = respiratory exchange ratio. ratio between O2 consumed and CO2 produced
RER = VCO2/VO2
RER for 1 glucose = 1.0
RER for 1 palmitic acid = 0.7
What fuel gives us more energy per gram and which costs most O2 per kcal?
Fat gives 9kcal/min
carbs give 4kcal/min
fat costs more O2 per kcal
what is BMR?
EE in resting conditions
2-3% decrease in BMR per decade due to
- decrease in Fat Free Mass
- depression of metabolic activity of lean tissues
What is MET?
metabolic equivalent of tasks. multiples of RMR
1 MET = 3.5ml/kg/min
What is fat max?
the intensity at which max rate of fat utilisation occurs.
decline explained by
- lower availability of FFA
reduced entry of FAs into mito
how is mechanical efficiency calculated?
external work accomplished / energy expenditure
What is oxygen deficit?
= lag in O2 uptake response until steady state occurs
what is EPOC?
delay in recovery of O2 consumption
what is the fast portion of EPOC and what occurs during this stage?
rapid decline in O2 uptake during 2-3 mins post exercise
resynthesis of ATP and PCr
O2 levels restored to myoglobin and haemoglobin
what is the slow portion of EPOC and what occurs?
occurs 3mins-1hr post exercise
resynthesis of lactate to glyocgen
HR and VE remain elevated
