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Aerobic EnergyProduction During

ExercisePED 5230

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Moderate Aerobic

Energy

50-85% of VO2max

Oxygen?

Fuel?

Lactate?

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Moderate Aerobic

Energy

Oxygen Supply =OxygenDemand...barely

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Moderate Aerobic

Energy Shift towards a greater contribution from

carbohydrates.

Why?

Advantage?

Disadvantage?

2,000 versus 72,000

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Moderate Aerobic EnergyGrams Kcals

Liver glycogen 110 451

Muscleglycogen 500 2050

Glucose 15 62

Total 625 2563Subcutaneous

and VisceralFat

7,800 73,320

IntramuscularFat 161 1513

Total 7961 74,833 From Wilmore andCostill

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Moderate Aerobic

Energy

Goal: maintain glucose levels

Muscle

Central nervous system

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Moderate Aerobic

Energy Liver glycogen

Glucagon

Catecholamines

Epinephrine

Norepinephrine

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Moderate Aerobic

Energy 1.0 1.5

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Glycogen Depletion

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Moderate Aerobic

Energy Prolonged exerciseCarbohydrates

Hypoglycemia

Glycogen Depletion

Fats and ketones Proteins

Gluconeogenesis

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FatBurnsin aCarbohydrate/

ProteinFlame

low pyruvateKetones

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Moderate Aerobic

Energy Ketones

acetoacetate beta-

hydroxybutyrate

Fuel for ST fibers,brain and nerves

Acidic

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Moderate AerobicEnergy

Near lactate threshold

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Fatigue

QuickTime and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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Fatigue

ATP or P?

Glycogen depletion?

> 1-2 hours

Hypoglycemia?

Direct - muscle

Indirect - CNS

QuickTime and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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Hypoglycemia

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Hypoglycemia

MusclesGlycogen & Fat

Heart

AdiposeFat

LiverGlycogen

Brain

O2

(inhibit)

low glucose

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Fatigue

Lactic acid or H?

Low oxygen supply?

QuickTime and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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Oxygen / Lactic

Acid

MusclesGlycogen & Fat

Lungs Heart

AdiposeFat

LiverGlycogen

Brain

O2 O2

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Fatigue

Central fatigue?

Central drive or command

Central governor

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Central Fatigue

MusclesGlycogen & Fat

Lungs Heart

AdiposeFat

LiverGlycogen

Brain

O2 O2

(inhibit)

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Heavy Aerobic Energy

> 85% of VO2max

Oxygen?

Fuel?

Lactate?

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Heavy Aerobic Energy

Oxygen supply less than demand

Muscles

Heart, too?

Anaerobic energy

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Heavy Aerobic Energy

Fuel

Carbohydrate

Aerobic

Anaerobic

PC?

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Heavy Exercise

Fatigue

Lactic acid?

CNS?

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Heavy Aerobic Energy

Lactate

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Heavy Exercise

If a person were to begin exercising at theirVO2max, how long would they be able to last

at that intensity?

Why?

What is the recommended percentage of VO2max to exercise at?