Lab 2 Flashcards
What is metabolism
all energy transformations that occur in the human body: cellular, chemical, mechanical
Nutrients + O2 –> ATP + heat
ATP –> cell work + heat
What do all energy transformations in the body produce
HEAT
The rate of heat production is proportional to what
metabolic rate
What are the two types of calorimetry
direct and indirect
if you use indirect calorimetry with O2 consumption what two types could it be
open circut or closed circut
What are the two ways to measure energy expenditure
- Direct Calorimetry: directly measures heat loss
- Indirect calorimetry: measures O2 consumption
- valid as measure of EE only when energy comes from oxidative pathway
- Nutrients + O2 –> heat + CO2 + H2O
What is VO2
RATE of oxygen consumption
VO2 is proportional to what
energy expenditure (EE) = during predominately aerobic tasks
1 L O2 = how many kcal
5kcal
an increased work rate requires a higher or lower rate of energy expenditure
higher
What is gross efficiency
mechanical power / metabolic power
Why is the human machine not 100% efficient
b/c energy is lost as HEAT
Gross efficiency varies with what 4 things
- work rate
- cadence
- fiber type
- contraction type
energy intake affects/does not affect energy expenditure and vice versa
affects
The rate of change of energy stores = what?
rate of change of energy intake - rate of change of energy expenditure
What is total daily energy expenditure (TDEE)
BMR + EAT + NEAT + TEF
What factors affect basal metabolic rate
fat-free mass (BMR is proportional)
Age
Sex (lower in females)
body fatness (BMR decrease 0.01kcal/min with every 1% increase in body fat)
genetics
caloric restriction/starvation
exercise
What is the metabolic equivalent (MET)
RMR is about 3.5 mL/kg/min
MET is unite that represents multiples of resting metabolic rate
1 MET = 3.5 mL/kg/min
if someone is working out at VO2 of 10.5mL/kg/min they are exercising at 3 METS
how to calculate VO2in open circut spirometry
VO2 = (volume of inspired O2 - volume of expired O2) per minute
how can energy expenditure be calculated for any VO2
1 L O2 == 5kcal
What are catabolic reactions
those that yield energy
What are anabolic reactions
those that require energy input
second law of thermodynamics
two isolated systems in contact with each other – differ in any way (temperature, density, pressure) will equalize if given the oportunity
When humans transform energy to do work what happens
heat is released
the rate of heat loss is measured how
measured as a reflection of the metablolic rate of an organism
metabolic rate is measured via what
direct or indirect calorimetry
metabolic rate measurement by direct calorimetry involves what
quantifying heat produced by resting or exercising being
calorie is what
heat required to raise the temperature of 1 g of water 1 degree Celcius
What do you need to know to measure metabolic rate using direct calorimetry
heat of water (1cal/degree/g), mass of water in jacket (g), heat loss (C) from subject to wall
is direct calorimetry for what type of metabolism
both aerobic and anerobic metabolism
When metabolism is predominately aerobic, the measurement of oxygen uptake can be used to do what
indirectly determine metabolic rate
determination of metabolic rate from oxygen uptake is termed what
indirect calorimetry
aerobic metabolism utilizes what 3 different substrates
carbohydrates
fats
proteins
all product ATP
- depending on substrate used relation between O2 consumption and E will vary
caloric expenditure of exercise is what
5kcal/L O2
What are the two types of spirometry used in indirect calorimetry
open or closed circut spirometry
Open circut spirometry determines what
rate of oxygen uptake (VO2) by subtracting amount of inspired oxygen (VIO2) - oxygen expired (VEO2)
What is the formula for VO2 (L/min)
VIO2(L/min) - VE(STPD)O2(L/min)
What is the formula for VO2 (L/min)
VIO2(L/min) - VE(STPD)O2(L/min)
Wha is the formula for VIO2
(VI)(FIO2)
What is VE(STPD)O2
(VE(STPD))(FEO2)
how does a douglas bag technique
2 way valve (Daniels valve) – atmospheric air and removal of expired air
What is collected into the douglas bags
volume of expired air –> determine concentration of fractional expired O2 and CO2 using gas machine PARVO
why dont oxygen and carbon dioxide fractions in inspired air need to be measured
they are a constant
How do you determine the rate of oxygen consumption – what parameters must be measured
volume of expired air (VE) – pulmonary ventilation (L/min)
fraction of expired oxygen (FEO2)
fraction of expired carbon dioxide (FECO2)
room temperature
barometric pressure
What is the constant for FIN2
0.7904
What is the constant for FIO2
0.2093
What is the constant for FICO2
0.0003
what is expired minute ventilation
measured as come out of mouth
saturated water vapor and at ambient temp and pressure
all expired minute ventilations collected in Douglass Bag corrected how
corrected to dry gas at standard temp and pressure using correction factor
VE(STPD)= VE(ATPS) x STPD correction factor
What is the equation for the STPD correction factor
= (273/273 + T(Celcius))(Pb-PH20/760)
What is gross mechanical efficiency (ME)
ratio of mechanical power (mechanical work rate) to metabolic power (rate of energy expenditure required to maintian specific mechanical work rate)
What are normal values for gross mechanical efficiency in humans
0-30% depending on intensity, exercise modality, contraction type, muscle fiber type
what is the main component of total daily energy expenditure (TDEE)
basal metabolic rate (BMR)
what is BMR responsible for
energy utilized to sustain all cellular, chemical, and mechanical work at rest (60-70% of TDEE)
what is thermic effect of food (TEF)
energy cost for digestion of food and absorption of nutrients – about 10% of TDEE
What is total daily activity thermogenesis (TDAT) broken down into
exercise activity thermogenesis (EAT)
non-exercise activity thermogenesis (NEAT)
thermic effect of food (TEF)
what is EAT
energy expenditure associated with sport specific exercising
what is NEAT
energy cost of all other forms of physical activity
when does energy balance occur
when energy intake = energy expenditure
rate of change of energy stores = rate of change of energy intake - rate of change of energy expenditure
What happens to the graph as an individual eventually reaches steady state
there is an O2 deficit == anerobic
what is the equation for STPD correction factor
(273/273+T(degree C)(Pb-PH2O/760)
What two conditions must be met during exercise for indirect calorimetry to reflect metabolic rate most accurately
1) must be primarily aerobic metabolism
2) must be at steady state
A man weighing 176 lbs runs at a pace of 9 min/mile. His VO2 at this pace is 39 mL/kg*min. If this man exercised at this intensity for 30 minutes each session, how many sessions would it take him to expend the equivalent of 12 lbs. Assume that 1 L O2 = 5kcal and 1lb = 3500 kcal
sessions = 90 (rounded)
if an individual were trying to lose weight it would be more advantageous to have a higher or lower gross efficiency
lower gross efficiency because you will burn more calories being less efficient with performing the same movement
What is the procedure during this lab
- run 3 conditions: rest, treadmil, ergometer
- VO2 measured during rest between 6-7 min and then exercising between 6-7 and 7-8 minute
