Energy expenditure Flashcards
indirect calorimetry
don’t measure heat, measures O2, CO2 and N
*inhale air with known composition and then monitor changes
Respiratory Quotient
- useful to tell which foods and energy sources
RQ = CO2 produced/ O2 consumed
RQ of carbs__
RQ of fat __
RQ of protein __
1
.7
.82
Total daily energy expenditure
resting metabolic rate: 60-75%
heat production - 10%
energy expended in activity 15-30%
BMR
the amount of energy that your body uses to fuel cellular activity at rest
Measuring BMR
gold standard: measure persons O2 uptake at rest NPO x 12 hrs * no exercise x 12 hrs before test lie still for 30-60 mins measure O2 and CO2
BSA - body surface area
the larger the surface area, the more energy you need to expend to maintain body temp
BMR x BSA x 24 hrs =
basal metabolic rate) x (body surface area
resting daily EE
BMR x BSA x 24 hours = calories needed per day
women have a __% lower metabloc rate
5-10
* also have larger % body fat, smaller muscle mass and smaller body surface
Does BMR increase or decrease with age?
decrease
if you increase % body fat what happens to LBM
decreases
expenditure with activity
gross energy expenditure = O2 consumed x duration of activity *convert to calories 45 minutes x 2L of O2 = 90 (1L O2 = 5kcal ) 90 x 5 = 450 kcal
1L of O2 = __kcal
5
BSA x BMR =
resting horly energy expenditure
Net energy expenditure =
exercise energy - BMR
30 yr old male exercises for 45 mins. height= 185 cm. BM = 75kg. Energy expenditure is 450 kcal. BSA = 2.05. How many calories did he burn with exercise alone?
- (BSA x BMR) = (2.05 x 36.8) = 75.4 kCal/hour
- 75.4 kCal / 60 min x 45 min = 56.58 k Cal from activity
- net energy = exercise energy - REE
450 - 56.58 = 393.44 kcal
net energy = 393.4 in 45 mins
endurance exerrcises depend on
VO2 max
lung function
genetics 30-30%
ME
mechanical efficiency = % of total enerfy expended that contributes to work ME = work output/ energy input x 100 W = (FxD) *more efficient, less O2 consumed most activities are 20-25% efficient
which muscle fibers are more efficient
type 1
if higher level of fitness __ level of energy expenditure
lower
increased BMI = __ energy expenditure
higher
becomes inefficient to keep walking at ___mph
4.8
The heavier you are,
the more energy you expend with activity
W= F x D
What happens when walking with weights
increase in SBP
increase in speed usually occurs from …
increasing the stride length
Children and running
increased stride frequency
shorter stride length
larger body surface area
results in increased energy expenditure
mot energy expensive walking terrain
hard surface
and walking uphill
contributors to energy consumption
age, body mass, speed, terrain, body comp and efficiency
clothing, haircut and shaving can decrease energy expenditure by __%
6
swimming is __ x less mechanically efficient than running
4
require energy to maintain buoyancy
overcome drag forces
heredity controls …
20-30% VO2 max
50% HR max
70% work capacity
* AA fatigue resistant
VO2 max for women is ___% below men
15-30
* also lower hemoglobin
lower percentage of FFM
higher percentage of body fat
VO2 max for boys = girls until what age?
12
VO2 max decreases after
25
and then 1% per year
direct Calorimetry
direct measure of heat
law of conservation
