When The Body Needs To Exercise More Than 90 Seconds What Type Of Respiration Occurs?

When the Body Needs to Exercise More Than 90 Seconds What Type of Respiration Occurs?

May 26, 2011 | By Warren Rosenberg

All exercise activities are fueled by the molecule adenosine triphosphate, or ATP. Unlike the gasoline that powers your car, ATP cannot be obtained from outside sources but is manufactured by your body from nutrients consumed in your diet. The manufacture of ATP within the cells of the body is driven by a series of chemical reactions collectively known as metabolic respiration. Depending on the length of time your physical activities continue, they use different metabolic respiratory pathways.

Short Intense Activities Use Stored ATP

For exercise activities that last no more than a total of six to 10 seconds, your stored reserves of ATP are all that is needed for fuel. ATP molecules stored locally in your muscle cells can be split apart, releasing their energy to drive your working muscles. This stored pool of ATP is regenerated following the completion of the short burst of muscle activity.

Activities Lasting Up to 60 Seconds Use Glycolytic Respiration

If your exercise activity lasts for anywhere between 10 and 60 seconds, locally stored ATP will not be able to provide sufficient energy. For these intermediate-length activities, ATP must be generated from carbohydrates through a series of metabolic respiration reactions called glycolysis. These reactions lead to a rapid production of ATP and require no oxygen. This energy supply mechanism is alternatively referred to as anaerobic respiration because no oxygen is required.

Activities Lasting 90 Seconds Use Aerobic Respiration

When your exercise activities persist for any period of time longer than 60 seconds, the needed ATP fuel must be produced by aerobic metabolic respiration. In the aerobic metabolic respiration pathway, molecules of either carbohydrate or fat are converted to ATP through a series of chemical reactions using oxygen. While this process produces ATP more slowly than the anaerobic pathway, it can continue for hours.

Aerobic Activities May Be Fueled by Carbohydrates or Fat

The long-term exercise activities that are driven by aerobic respiration can be fueled by either carbohydrates or fat. Because the chemical reactions that break down fat progress at about one-third the speed of those that break down carbohydrate, fat is the preferred fuel for low- and moderate-intensity exercise, while carbohydrate is the preferred fuel for high-intensity activities.