• knowing metabolic responses to exercise allows evaluation of effects of exercise
• allows relative comparisons to resting or maximal responses as well as description of absolute responses
• absolute VO₂
• multiples of resting metabolic rate (MET)
• percent of VO₂ max
• allows estimation of energy cost of exercise and estimation of efficiency

-the difference between the total oxygen actually consumed and the total that would have been consumed if a steady state VO₂ had been achieved

-lag in oxygen uptake at the beginning of exercise

-suggests anaerobic pathways contribute to total ATP production

where is O₂ deficit on VO₂ vs time graph?

(need whiteboard)

-the amount of oxygen consumed after exercise in excess of the amount that would be used at rest without prior exercise, implies that the debt = deficit

-debt > deficit

-misnomer

-excessive post exercise oxygen consumption

-the preferred term for the excess oxygen consumed above a resting baseline during recovery from exercise

-reflects the size of the anaerobic contribution to ATP requirement of exercise

-ex. larger deficit = larger ANAEROBIC contribution

-because other factors contribute to post-exercise consumption, thus making the term debt a misnomer

-debt due solely to paying back the deficit before aerobic processes could meet demand

submaximal (light to moderate exercise) vs supra-maximal (heavy exercise)

(need whiteboard)

it takes trained athletes a shorter time to get to their max VO₂

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alalactid vs lactacid phases

*now inappropriate terms*

- alactacid: fast component of O₂ debt (rapid decline in VO₂, no decline in LA)

-lactacid: slow component of O₂ debt (slow decline in VO_{2, decline in LA)}

[image]

traditional oxygen debt theory

*incorrect*

1.)rapid portion: no reduction in lactic acid, aka alactacid phase

-thought to be repayment of ATP-CP debt

2.) slow portion: reduction in lactic acid seen, aka lactacid phase

-thought to be repayment of anaerobic glycolytic debt

*it is now known that LA enters and leaves the blood rapidly during and after exercise and that its fate is oxidation during and after exercise*

comparison of oxygen deficit and debt during light and heavy eercise

(need whiteboard)

• EPOC
• elevated VO₂ for several minutes immediately following exercise
• "fast" portion of O₂ debt
• resynthesis of phosphagen stores (ATP and CP)
• replacing muscle and blood O₂ stores
• "slow" portion of O₂ debt
• elevated HR and breathing, INC energy need
• elevated body temp, INC metabolic rate
• elevated E and NE, INC metabolic rate
• conversion of LA to glucose (gluconeogenesis)

-only 20% of oxygen debt is used to convert lactate into glucose

-elevated oxygen consumption post exercise is not due solely to paying back the energy "borrowed" from other sources

-the term oxygen debt should be abandoned

-resynthesis of PC in muscle

-lactate removal

-restoration of muscle and blood oxygen stores

-elevated hormones

-post-exercise elevation of HR and breathing

-elevated body temp

RQ (respiratory quotient): VCO₂/VO₂ @ the cellular level

RER (respiratory exchange ratio): VCO₂/VO₂ for the whole body

that produced during the process of oxidation of fuel substrate, ex. CHO, fatty acids

-product of metabolic and non-metabolic CO₂

-RER must eventually equal RQ

-during onset and offset of exercise and during hard exercise, RER ≠ RQ due to CO₂ storage changes

-greater in CHO than fat

-RER > 1 because of non-metabolic CO₂

~35% of VO₂ max as exercise increases there is a progressive increase in the contribution of CHO as fuel source

[image]

-@ 50% of VO₂ max

-thus important to consider both the total rate of energy expenditure and percentage of energy that is derived from fat metabolism

[image]