Lab 3 + 4 prep Flashcards
% muscle mass to total mass
40% avg
- large organ
skeletal muscle contribution to resting metabolic rate
- change with maximal exercise
20% resting metabolic rate
- can increase 100-fold from rest to exercise
- very fast at turning on
ATP storage?
no
- when made, utilized immediately
purpose of metabolic pathways
produce electron donors
- NADH and FADH2
aerobic metabolism
- production of ATP
oxidative phosphorylation
- fat and carbs
anaerobic metabolism
- production of atp
glycolysis and phosphocreatine
- substrate phosphorylation
- carb only
when is anaerobic energy required
transitions - from one power output to another sprinting - 90-100% VO2 max reduced O2 availability - swimming and altitude
avg VO2 max
3.5L/min
improving anaerobic metabolism
anaerobic glycolysis - can increase with training PCr - very small increase - 10-20% by increasing muscle mitochondria (more muscle) - artificial increase with supplements
humans energy efficiency
23-27%
- designed to keep ourselves warm
direct calorimetry
heat production
- measure energy burned by heat produced
- food stuff + O2 –> atp + heat + CO2
indirect calorimetry
CO2 production - spirometry
- measures O2 used
- food stuff + O2 –> atp + heat + CO2
2 types of spirometry
1) closed - chamber - flow through of air
2) open, measures inspired or expired **
how to measure metabolic rate
3 inputs
- in/expired CO2
- in/expired O2
- work output
fraction inspired air
- O2
- CO2
- N2
O2 - 20.93%
CO2 - 0%
N2 - 79.04%
fraction expired air
- O2
- CO2
O2 - 16.5%
CO2 - 2.5%
respiratory exchange rate (RER)
Glucose - 6O2 --> 6CO2 - RER = 1 Fat - 23O2 --> 16CO2 - RER = 0.7
Resting relative VO2 (to mass)
3.5-4.0 mL/kg/min
reason for RER > 1
1) acid produce high intensity
- buffering produces CO2
2) hyperventilation
- body exhales mores store
RER caloric equivalent (Kcal/L O2)
- carbs and fat
carbs
- 5.047 kcal/L
fat
-4.686 kcal/L
RER at:
- low intensity
- mid intensity
low intensity
- RER 0.9
energy expenditure calculation
Kcal = VO2 x RER caloric equivalent x time
relative contribution of fat and carb to energy expenditure
% kcal from fat = [(1-RER)/(1-0.7)] x 100
% kcal from carb = 100 - (%kcal from fat)
energy from fat
food - 9.3 kcal/g
body - 7.7 kcal/g
- body is lower because of connective tissue
energy from carbs
4.1 kcal/g
measurement of efficiency
(power x time) / (Ve x KJoules)
- avg 25%
how metabolic cart calibration works
- turns volts into meaningful value for gas fractions
- limitations of VO2 measurement relates to how accurate the gas calibrations are
- also calibrate flow-volume (3L syringe)
valve used to measure expired air only
rudolf valve
how to calibrate Monark bike power output
LODE bike
- 1 point calibration - at one power output
- multiple better
RER accuracy
not ideal measure
- O2 exhaled not just from muscle
- other tissues as well
- 85% muscle during exercise (blood flow) so a good indicator
assumptions for RER use
- subject in steady state
- other fuels minimal contribution (protein, acetate)
- hyperventilation a problem at max exercise
- no other “non-fuel” O2 use
- de novo synthesis of fat in adipose tissue
- CO2 production acidic muscle (bicarbonate buffering)
indicators VO2 max is reached
- 95% predicted max HR
- RER > 1.1
- VO2 plateau ***
- Ve plateau
- blood lactate >10mM
predicting VO2
submax VO2 test
- go to 85% max HR
- record 2 HR values >110bpm
- estimate VO2 max at max HR
- estimated VO2 for specific power ouputs
benefits and limitations to VO2 submax test
benefits
- cost
- safer
limitations
- estimates all measures
- assumes constant efficiency between individuals
- only 2 HR values
- not very accurate for athletes or active people
VO2 max test name
Astrand “continuous test”
