Lactic acid is a byproduct of anaerobic metabolism, in which the body produces energy without using oxygen. Since the discovery of lactic acid, the popular notion has been that it is responsible for muscle fatigue and also tissue damage induced by the lactic acid following an intense workout.
Does lactate contribute to fatigue?
Intracellular acidosis due mainly to lactic acid accumulation has been regarded as the most important cause of skeletal muscle fatigue.
Why does blood lactate cause fatigue?
In conclusion, we found that blood lactate concentration reflects muscle metabolism, rather than respiratory and circulatory responses, and that muscle activity might convey fatigue-related information to the brain during load intensity when muscle fatigue occurs.
How does hydrogen ions cause fatigue?
In addition, many textbooks report that muscle fatigue is mainly the result of a decrease in pH within the muscle cell due to a rise in hydrogen ion concentration ([H+]) resulting from anaerobic metabolism and the accumulation of lactic acid.
Does lactic acid or lactate cause fatigue?
Let’s examine a few popular misconceptions. The accumulation of lactate causes fatigue in muscles. Lactate does not cause fatigue, and on the contrary is a useful and efficient fuel source[2]. Lactic acid can be measured in the blood using a lactate analyzer.
What factors contribute to muscle fatigue?
Specifically, metabolic factors and fatigue reactants during the process of contraction, such as hydrogen (H+) ions, lactate, inorganic phosphate (Pi), reactive oxygen species (ROS), heat shock protein (HSP) and orosomucoid (ORM), also affect muscle fatigue.
What causes muscle fatigue at the cellular level?
Glycolysis converts glucose to pyruvate, water and NADH, producing two molecules of ATP. Excess pyruvate is converted to lactic acid which causes muscle fatigue. Cellular respiration produces further molecules of ATP from pyruvate in the mitochondria.
What causes muscle weakness and fatigue?
Muscle weakness is commonly due to lack of exercise, ageing, muscle injury or pregnancy. It can also occur with long-term conditions such as diabetes or heart disease. There are many other possible causes, which include stroke, multiple sclerosis, depression, fibromyalgia and chronic fatigue syndrome (ME).
