Energy Flashcards
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What are the 3 componets of energy expenditure?
- Basal Energy expenditure
- Thermic Effect of Food
- Energy Expenditure of Physical activity
What other factors impact energy expenditure>
Cold adaption, medications, and emotions
Describe what BEE is
The energy needed at complete rest. When you first wake up in the morning
What percentage of total daily expenditure is BEE?
60%
What is the difference between RMR and BEE?
RMR is a bit higher because it includes sedentary activities
Describe TEF
The energy needed for digestion, absorption and storage of food
How much of the daily expenditure is TEF?
5-15%
Describe what EEPA is?
The sum of all physical exercise
What is included in EEPA?
Exercise activity thermogenesis ( planned exercise) and non-exercise activity thermogenesis
What is the direct way of measuring energy expenditure?
You would measure the changes in body temperature (heat production)
Why would you measure body temperature in the direct way of getting energy expenditure?
Due to the inefficiencies of of the body systems, it produces heat which can be measured
What are the indirect ways of measuring energy expenditure?
Oxygen consumption as a marker of heat production and doubly labelled water
Why do we measure oxygen consumption when we are measuring energy expenditure?
Oxygen is a marker of heat production. The body does not store a lot of oxygen (hence us breathing constantly). Most aerobic reactions use oxidative substrates for heat production (energy).
What does a respiratory quotient represent?
CO2 produced / O2 consumed
Explain doubly labelled water as a measure of energy expenditure.
Ingest 2 labelled isotopes 2H2O18, O18 will leave as CO2 and H2O. difference between the 2 isotopes + total water pool. Unlabelled CO2 from oxidized fuel
Do you need to measure TEF, why or why not?
No, because TEF is very similar for everyone
How much variance is there in BEE/RMR?
> 80%
What contributes to the variance in BEE/RMR
Free fat mass and to a lesser degree age and gender
Food restriction results in…
decreased BMR