Lecture 10 Flashcards
What factors determine how much oxygen is consumed?
Oxygen uptake during exercise is dependent upon exercise intensity and duration.
What is the energy source during the oxygen deficit phase?
Creatine Phosphate and glycolysis are the primary energy source during the oxygen deficit.
How many phases does Excess Post-Exercise consumption have?
Excess Post-exercise Consumption (EPOC) has 3 distinct phases due to declining oxygen demand.
What is EPOC?
EPOC is the excess oxygen consumption that remains after exercising.
How are calories in food measured?
How are calories lost measured?
Oxygen uptake can be used to measure the calories burned performing a certain exercise.
Calories in food are discovered via bomb calorimetry.
How much of the energy generated by metabolism goes into work?
20% of energy generated is used to generate work. the rest is lost as heat.
What are the theories behind the “O2 deficit”?
O2 transport limitation Metabolic inertia (mitochondria slow at creating enzymes that are necessary for metabolism) An interaction of both factors.
What is the VO2 max?
VO2 increases with power output until it hits a maximum amount. This is the VO2 max.
What causes VO2 drift?
80% due to active muscle changes.
Recruitment of lower efficiency type 2 fibers.
Reduced P-O coupling
Elevated muscle temperature
Elevated catecholamines
O2 cost of ventilatory and cardiac work
increase in fat metabolism requires more oxygen
What causes EPOC?
Resynthesis of ATP and CP
Restoration of myoglobin O2 stores
Elevated HR, ventillation, temperature and hormones.
Increased FFA metabolism
Mitochondrial “uncoupling”
Glycogen resynthesis
What happens to excess FFA present in bloodstream after exercise is over?
Glycogen is preferentially resynthesized while fat is oxidized when it’s available post exercise.
What are some characteristics of Cp resynthesis?
Is rapid and O2 dependent.
larger muscle oxidative capacity makes creatine phosphate regeneration faster.
What are the metabolic fates of lactate?
Lactate gets oxidised in skeletal and cardiac muscle. (active recovery enhances lactate removal)
It is a substrate for glycogen synthesis
It can be converted to other metabolites
Lactate does NOT increase VO2 or cause muscle soreness.
How does lactic acid affect post exercise O2 consumption?
Induced lactacidemia does not affect postexercise O2 consumption
What is better active or passive recovery?
Active recovery enhances lactate removal.
