Originally posted by Joe 1320
Lactic acid - friend or foe?
Lactic acid (lactate) is not:
* responsible for the burn in the leg muscles when exercising very fast
* responsible for the soreness you experience in the 48 hours following a hard session
* a waste product
Lactate, which is produced by the body all day long, is resynthesized by the liver (Cori Cycle) to form glucose which provides you with more energy. Sounds like a friend to me.
Lactate Shuttle
The lactate shuttle involves the following series of events:
* As we exercise pyruvate is formed
* When insufficient oxygen is available to breakdown the pyruvate then lactate is produced
* Lactate enters the surrounding muscle cells, tissue and blood
* The muscle cells and tissues receiving the lactate either breakdown the lactate to fuel (ATP) for immediate use or use it in the creation of glycogen
* The glycogen then remains in the cells until energy is required
65% of lactic acid is converted to carbon dioxide and water, 20% into glycogen, 10% into protein and 5% into glucose.
Hydrogen ions
The breakdown of glucose or glycogen produces lactate and hydrogen ions - for each lactate molecule, one hydrogen ion is formed. The presence of hydrogen ions, not lactate, makes the muscle acidic which will eventually halt muscle function. As hydrogen ion concentrations increase the blood and muscle become acidic. This acidic environment will slow down enzyme activity and ultimately the breakdown of glucose itself. Acidic muscles will aggravate associated nerve endings causing pain and increase irritation of the central nervous system. The athlete may become disorientated and feel nauseous.
Lactic acid (lactate) is not:
* responsible for the burn in the leg muscles when exercising very fast
* responsible for the soreness you experience in the 48 hours following a hard session
* a waste product
Lactate, which is produced by the body all day long, is resynthesized by the liver (Cori Cycle) to form glucose which provides you with more energy. Sounds like a friend to me.
Lactate Shuttle
The lactate shuttle involves the following series of events:
* As we exercise pyruvate is formed
* When insufficient oxygen is available to breakdown the pyruvate then lactate is produced
* Lactate enters the surrounding muscle cells, tissue and blood
* The muscle cells and tissues receiving the lactate either breakdown the lactate to fuel (ATP) for immediate use or use it in the creation of glycogen
* The glycogen then remains in the cells until energy is required
65% of lactic acid is converted to carbon dioxide and water, 20% into glycogen, 10% into protein and 5% into glucose.
Hydrogen ions
The breakdown of glucose or glycogen produces lactate and hydrogen ions - for each lactate molecule, one hydrogen ion is formed. The presence of hydrogen ions, not lactate, makes the muscle acidic which will eventually halt muscle function. As hydrogen ion concentrations increase the blood and muscle become acidic. This acidic environment will slow down enzyme activity and ultimately the breakdown of glucose itself. Acidic muscles will aggravate associated nerve endings causing pain and increase irritation of the central nervous system. The athlete may become disorientated and feel nauseous.
Comment