Energy Systems & Exercise

Energy systems category covers the various ways in which the body generates and uses energy and includes anaerobic respiration, aerobic respiration, krebs cycle, human digestive system, oxygen debt as well as the long term and short term effects of exercise on the body.

Digestive system diagram

The primary function of the digestive system is to break down food both mechanically and by the use of enzymes, so that it can be used by the body for energy and cell growth and repair. It consists of a large number of organs and processes with the combined functions of breaking down our food into smaller molecules which can be used to produce energy and for other nutritional purposes; and excreting the waste consumed and produced by the system.

Anaerobic respiration is when the body produces energy for exercise without oxygen. The anaerobic energy system kicks in in the first few minutes of all exercise, before there is suffiecient oxygen available at the muscles for aerobic metabolism. It is also used for fast, powerful bursts of energy, for which the aerobic system is insufficient. There are two systems within Anaerobic metabolism, which are the ATP-PC system and the lactic acid system.

Krebs cycle and aerobic system

Aerobic metabolism means 'with oxygen' and occurs when energy is produced in the body from chemical reactions that use oxygen. The aerobic system produces the largest amounts of energy, although at the lowest intensity such as in long distance running. This energy production can be sustained for long periods of time as long as breathing can supply the lungs with enough oxygen.

When you begin to exercise your body must immediately adjust to the change in activity level. Energy production must increase to meet demand with changes to the predominant energy system and fuel source occurring throughout the exercise in order to maintain the required level of performance.

Exercise affects the circulatory system, respiratory system and the muscles. Short term effects occur immediately as we begin to exercise. Long term effects are more concerned with adaptive changes over time with regular exercise.

What is oxygen debt? When you have a short intense burst of exercise such as sprinting you generate energy for this anaerobically or without oxygen. When you stop exercising you are still breathing heavily. This is your body taking in extra oxygen to 'repay' the debt. Well, that is the simple solution but there is a little more to it if you want to look a bit deeper.

What is cellular respiration? Cellular Respiration is the process that takes place in cells to convert food into energy. This process is also known as internal respiration. In order to release the maximal amount of energy, the molecules of Carbon, Hydrogen, Oxygen and Nitrogen which make up our food are stored as a high energy molecule known as ATP or Adenosine Triphosphate.

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