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Home > PDHPE > Core 2 - Factors Affecting Performance > How does the body respond to aerobic training? > How does the body respond to aerobic training?
Answers
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At low to moderate exercise intensity,
there is an initial rise in the lactate levels which is
relatively quick. At the five-minute mark, these levels
plateau and remain constant for the duration of the
exercise. This is because the body is able to cope with
the exercise load quite easily i.e. it can produce the
energy it needs.
Note: This level of activity is predominantly aerobic, where energy is supplied largely in the presence of oxygen. The amount of oxygen available is sufficient to remove lactic acid from the bloodstream. Lactate levels will remain steady as long as exercise intensity remains the same.
- Moderate to heavy exercise shows a
gradual build-up of lactic acid in the body. When the
intensity of exercise is moderately heavy, the body's
production of lactic acid is becoming unbalanced, i.e. it
is being produced more quickly than it can be removed from
the blood. The slow build-up indicates that the aerobic
energy system is being supported by the anaerobic system at
this higher workload intensity. Oxygen is required to
resynthesise lactic acid. If there is insufficient oxygen
to supply the energy needs for the body, there will not be
enough oxygen to remove the lactic acid that is building in
the bloodstream.
- When the intensity of exercise is heavy there is a constant and relatively rapid rise in the level of blood lactate. The high level of exercise intensity makes it difficult to supply the amount of oxygen the body needs. As a result, the lactic acid being produced can not be removed. The graph stops at 10 minutes because of the build-up of lactic acid in the bloodstream. This causes rapid fatigue and forces the athlete to stop exercising.
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