LEWIS: The recovery process: EPOC Flashcards
During recovery the body takes in
increased amounts of oxygen
The oxygen is transported to the working muscles to maintain elevated rates of
aerobic respiration
This surplus energy is used to
help return the body to its pre-exercise state -EPOC
EPOC stands for
Excess Post-exercise Oxygen Consumption
Start to exercise, insufficient oxygen is distributed to the tissues for all the energy production to be met aerobically, so the 2 anaerobic systems have to be
used
the amount of oxygen that the subject was short of during the exercise is known as the
oxygen deficit
the oxygen deficit is compensated for by the surplus amount of oxygen or oxygen debt that results from
EPOC
EPOC is divided into 2 components:
Fast/Alactacid
Slow/Lactacid
Alactacid component involves:
- Resynthesis of ATP and PC stores
- Resaturation of myoglobin with oxygen
- Elevated rates of respiration to supply oxygen to provide the energy for ATP production and PC replenishment
(ALACTACID) complete restoration of PC takes up to 3 minutes, but 50% of stores can be replenished after only 30 seconds, during which time approximately how much oxygen is consumed
2-3 litres
(ALACTACID) myoglobin has a high affinity for oxygen. It stores oxygen in the muscles, where it is released into the mitochondria for
energy provision
(ALACTACID) after exercise, oxygen stores in the mitochondria are limited. The surplus of oxygen supplied through EPOC helps replenish these stores, taking up to
2 minutes and using approximately 0.5 litres of oxygen
(ALACTACID) is replaced very quickly if
exercise is highly aerobic
Lactacid component involves:
- Removal of excess lactic acid from muscle cells/blood
- Maintain high heart rate
- Maintain breathing rate
- Maintain body temperature
- Restoration of glycogen stores (from glycogen stores in body and carbohydrate intake)
(LACTACID) full recovery may take up to an hour depending on the
intensity and duration of the exercise
(LACTACID) lactic acid can be removed in the following ways:
- oxidation into CO2 and H2O in the inactive muscles and organs
- used as an energy source
- conversion into glycogen - then stored in muscles/liver
- conversion into protein
- conversion into glucose
- excreted in sweat/urine
Size and duration of EPOC varies with the intensity of exercise, from which you are recovering. Intense exercise require more oxygen for recovery, and recovery will take
longer
The longer the duration of the exercise, the longer
recovery will take
The level of fitness affects duration of EPOC, fitter the performer the
quicker the recovery
During lactacid component of EPOC, glycogen stores are replenished. The replacement of glycogen stores depends on the
type of exercise undertaken and when and how much carbohydrate is consumed following exercise
(lactacid) glycogen replenishment may take several days to complete the restoration of glycogen after a marathon, but a significant amount of glycogen can be restored in less than an hour after
long-duration, low-intensity exercise
(lactacid) eating a high-carbohydrate meal will accelerate glycogen replenishment as will…
eating within an hour following exercise
(lactacid) increase in breathing and heart rates is important to assist recovery where extra oxygen is required to return the body to its pre-exercise state. However, the increase in breathing and heart rates requires additional extra oxygen to provide energy for the
muscles of the heart and respiratory system
(lactacid) the continuation of sub-maximal exercise (such as cool-down) will keep hormone levels elevated and this will
keep respiratory and metabolic levels high so that extra oxygen can be taken in
(lactacid) when temperature remains high, respiratory rate will also remain high and this will help the performer take in more oxygen during recovery. However, extra oxygen is required to fuel this increase in temperature until
the body returns to normal
Fate of lactic acid due after EPOC:
- Oxidation into CO2 and H2O - 65%
- Conversion into glycogen (then stored in muscle and liver=cori cycle) - 20%
- Conversion into protein - 10%
- Conversion into glucose - 5%
The lactate shuttle is a recovery process after
intense exercise
(LACTATE SHUTTLE) Small proportion of lactic acid produced is released into the bloodstream and used directly as a fuel by the heart muscle and liver to produce
Blood glucose and glycogen
2 methods by which the body deals with an excess of lactic acid:
- Converting lactic acid to pyruvate (oxidation) - aerobic process occurs
- Transporting the lactic acid to the liver via the bloodstream where it can be reconverted to glucose (cori cycle)
(LACTATE SHUTTLE) is the reverse process to glycolysis and requires energy from
ATP breakdown
Implications of recovery for interval training: There is only a short interval between bouts of exercise, the level of phosphagen stores gradually reduces thereby reducing the energy available for the later bouts. This:
- Stresses the ATP and PC storage and forces the muscle cells to adapt by storing more of these quantities
- Cells will adapt by improving their ability to provide O2 and hence increase the possible size of the alactic component
(Implications of recovery for interval training) anaerobic interval training has shown that 30 second bouts of exercise increase the activities of glycolytic enzymes, this increase in glycolytic capacity will allow the muscle to
develop greater tension for a longer period of time as the muscle tissue increases its lactate tolerance
Lactic acid removal: cool down continues to provide oxygen to the skeletal muscle, this therefore enhances
oxidation of lactic acid and ensures that less lactic acid remains in tissues, less muscle soreness (DOMS)
