Energy Systems in the Body

The body has two main energy systems (aerobic and anaerobic energy system). Energy is needed for maintenance, growth, everyday activities and exercise. The amount of energy required during exercise by the body depends on the intensity and duration of exercise. Put simply exercising harder for longer periods requires more energy. The aerobic energy system is usually the first to be used, when you’re active the demand for energy increases, as does the demand for more oxygen by the muscles. This extra demand for oxygen is met by an increase in the rate and depth of breathing and an increase in blood supply due to increased heart rate.When the oxygen required by the body cannot be met, the body will switch to a different energy system (the anaerobic energy system), which produces energy without the use of oxygen.