The human body gets its source of energy from food consumed, anything containing glycogen, fats and proteins. Carbohydrates are a big source of glycogen which can be stored in the muscles and liver then converted to glucose when required. The section on 'Respiration' details the use of glucose in the production of ATP.
The energy source depends on how a muscle is being used. The body requires 15% more oxygen to oxidise fat than to break down carbohydrate, therefore it is obvious that although fat produces more ATP, when oxygen is in limited supply the body has to burn carbohydrate.
Short Intense Work Longer Anaerobic Work Aerobic Work
Last updated by Andrew Robinson 26th May 2004