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Flashcards in Lecture 10 Deck (16)

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.


What factors affect glycogen resynthesis after exercise?

Glycogen synthase is activated

More GLUT4 causes more glycogen regeneration

CHO ingestion increases glycogen resynthesis

Muscle damage reduces glycogen resynthesis

When glycogen levels are really low they overcompensate and stores become much higher next time around.