Energy Transfer during Long Duration/Low Intensity Exercise

Oxygen consumption during exercise
1. Oxygen consumption: the amount of oxygen we use to produce ATP
  1. VO2
2. At rest, approx 0.3-0.4 litres of oxygen consumed per min
3. Start of exercise, more oxygen used to provide more ATP so oxygen consumption increases
4. As intensity increases, oxygen consumption increases until max oxygen consumption
  1. VO2 max
  2. 3-6 litres per min
5. Start of exercise, insufficient oxygen distributed to tissues for all energy to be provided aerobically
  1. Takes time for circulatory system to respond to increase in demand for oxygen
  2. Takes time for mitochondria to adjust rate of aerobic respiration
  3. Energy provided anaerobically so satisfy increase in demand for energy until circulatory system & mitochondria can cope
    1. Sub-maximal oxygen deficit
Oxygen consumption during recovery
1. Excess Post-exercise Oxygen Consumption (EPOC)
2. Fast component
  1. Uses extra oxygen taken in during recovery to restore ATP & PC, and to re-saturate myoglobin with oxygen
  2. Complete PC restoration takes 3 mins, 50% restoration takes 30 secs
    1. Approx 3 litres oxygen consumed
  3. Myoglobin has high affinity for oxygen
    1. Stores oxygen in sarcoplasm that has diffused from haemoglobin in blood
      1. After exercise oxygen stores in the myoglobin are limited
        Surplus of oxygen supplied through EPOC helps replenish oxygen stores, taking 2 mins using 0.5L of oxygen
3. Slow component
  1. Removal of lactic acid
    1. When oxygen is present, lactic acid can be converted back into pyruvate & oxidised into CO2 & H2O in the inactive muscles and organs. Can then be used by the muscles as an energy source
    2. Transported in the blood to liver where it's converted to blood glucose & glycogen
      1. Cori Cycle
    3. Converted into protein
    4. Removed in sweat and urine
    5. Majority of lactic acid can be oxidised into mitochondria
      1. Cool-down can accelerate its removal
        Exercise keeps metabolic rate of muscles high and keeps capillaries dilated
        Oxygen can be flushed through, removing accumulated lactic acid
  2. Begins as soon as lactic acid appears in muscle cell
    1. Will continue using breathed oxygen until recovery is complete
      1. Can take up to 5-6L of oxygen in first half hour recovery, removing up to 50% of lactic acid
  3. Maintenance of breathing and heart rates
    1. Maintaining breathing and heart rates requires extra oxygen to provide energy needed for respiratory and heart muscles
      1. Assists recovery as extra oxygen used to replenish ATP & PC stores, re-saturate myoglobin and remove lactic acid, returning body back to pre-exercise state
  4. Glycogen replenishment
    1. Glycogen main energy provider and is fuel for aerobic and lactic acid systems
      1. Will be depleted during exercise
    2. Replacement of glycogen stores depends on type of exercise undertaken and when & how much carbohydrate is consumed following exercise
    3. May take several days to complete restoration of glycogen after a marathon, but in less than 1 hour after high duration, short intensity exercise
    4. Significant amount of glycogen can be restored as lactic acid and is converted back to blood glucose & glycogen in liver via Cori cycle
    5. Eating high carbohydrate meal will accelerate glycogen restoration, as will eating within 1 hour of following exercise
    6. 2 nutritional windows for optimal recovery
      1. 30 mins after exercise
        Both carbohydrates & proteins should be consumed in 3:1 or 4:1 ratio
        Combination helps body to re-synthesise muscle glycogen more efficiently than just consuming carbohydrates on their own
      2. 1-3 hours after exercise
        Meal high in protein, carbohydrate, and healthy fat should be consumed
  5. Increase in body temperature
    1. When temp remains high, respiratory rates will remain high
    2. Will help performer take in more oxygen during recovery
    3. Extra oxygen from EPOC needed to fuel increase in temp until body returns to normal

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Energy Transfer during Long Duration/Low Intensity Exercise

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	Created by Wesley Spearman over 6 years ago