energy expenditure Flashcards
why is energy expenditure data needed
needed when trying to predict the energy needs of individuals and populations.
what percentage of energy expenditure is used up in each area of expenditure
60% BMR - this fluctuates from each individual and over lifespan
10% dietary and cold induced thermogenesis - e.g. when we eat food we produce heat
15-30% physical activity
how do men expend more energy than women
due to muscularity and size
what does post prandial mean
after eating
what is the basal metabolic rate (BMR)
Minimum rate of energy utilisation needed to sustain life
Energy needed to sustain life – respiration, circulation etc.
how is BMR measured
Measured in a fasted individual lying at complete mental & physical rest in a warm, dimly lit room at least 12h after the last meal.
what is resting metabolic rate (RMR) compared too BMR
If any of these conditions for BMR are not met, EE may be termed resting metabolic rate (RMR).
It is higher than BMR (approx. 1.1 x BMR) as it takes account of a degree of activation of the sympathetic nervous system.
what is sleeping metabolic rate (SMR) compared to BMR
SMR gives slightly lower values
(5-10% lower) than BMR.
what percentage of the liver contributes to the BMR percentage
27%
what percentage of the brain contributes to the BMR percentage
19%
what percentage of the muscle contributes to the BMR percentage
18%
what percentage of the kidney contributes to the BMR percentage
10%
what percentage of the heart contributes to the BMR percentage
7%
what percentage of the rest of the organs contributes to the BMR percentage
19%
what is postprandial thermogenesis (PPT)
The increase in Energy expenditure caused by ingestion of food.
E required for the digestion, absorption, transport & storage of nutrients.
Accounts for ~10% of daily Energy expenditure, but depends on food composition and its metabolic fate.
Starts within minutes of eating and rises to a maximum in ~ 3h. The effect can continue for ~15h.
what is diet induced thermogenesis (DIT)
is used to describe longer term effects of diet on Energy expenditure
what can the thermic effect of food also be referend to as
Specific dynamic effect of food
Thermogenic effect of food
Dietary thermogenesis
Diet induced thermogenesis
what does cold induced thermogenesis include
Includes both shivering and “non shivering thermogenesis”.
how does cold induced thermogenesis affect BMR
Increase in BMR when heat lost to environment is increased by cold, air movement, lack of shelter/clothing.