Depending upon whether the body uses oxygen or not in order to perform specific exercises determines if the exercise is aerobic (with oxygen) or anaerobic (without oxygen).

The anaerobic respiratory system supplies energy very quickly for sports such as vaulting in gymnastics or throwing a javelin where the activity only lasts a few seconds.

There are two types of anaerobic energy systems. These are:

1. the creatine phosphate anaerobic system
2. the lactic acid anaerobic system

The creatine phosphate (CP) anaerobic system supplies energy faster than all other energy systems.

It is used for explosive, high-intensity contractions, such as in sprinting 100 metres, but it can only supply energy for about ten seconds.

Oxygen debt

It is the lack of oxygen and the build up of lactic acid that causes fatigue.

Both these systems require oxygen to restore them which is called an oxygen debt.

After taking part in exercise, a person continues to breathe more deeply and rapidly than when at rest to take in additional oxygen to repay this oxygen debt.

The oxygen is then used to:

• break down lactic acid to carbon dioxide and water
• replenish the creatine phosphate stores

The aerobic respiratory system is responsible for producing the majority of our energy while our bodies are at rest or taking part in low-intensity exercise for long periods of time, such as jogging or long-distance cycling.

Carbohydrates and fats supply the energy for the aerobic energy system and can supply energy for long periods of time.

Carbohydrate food sources include rice; bread; potatoes; bananas and energy drinks.

The aerobic respiratory system is responsible for producing the majority of our energy while our bodies are at rest or taking part in low-intensity exercise for long periods of time, such as jogging or long-distance cycling.