Exercise lactate

Ginseng extract alters the mechanism of fuel homeotasls during prolonged exercise (Lactate, Glucose, Fatty acid)... 

Gleeson, T. (1996) Post-exercise lactate metabolism a comparative review of sites, pathways, and regulation. Annu. Rev. Physiol. 

Hyperventilation in lactic acidosis is more intense than in other forms of metaboHc acidosis. It is believed that this is because of the participation of the respiratory center in lactic acid production and the resulting greater local acidification of the respiratory center. During exercise, lactate levels may increase significantly, from an average normal concentration of -0.9 mmol/L to 12 mmol/L. However, under normal conditions, the lactate is rapidly metabolized so that the "acidosis is only transient. 

During strenuous exercise, lactate is produced in muscle cells under anaerobic conditions. After passing through blood to the liver, lactate is converted to glucose by gluconeogenesis. 

Gluconeogenesis involving lactate is especially important. As might be expected, this process follows a separate and different pathway from glycolysis. During active exercise, lactate levels increase in muscle tissue, and the compound diffuses out of the tissue into the blood. It is transported to the liver, where lactate dehydrogenase, the enzyme that catalyzes lactate formation in muscle, converts it back to pyruvate ... 

The lactate accumulation during intense anaerobic exercise was implicated as a possible fatigue factor as early as the beginning of this century (Fletcher and Hopkins, 1907). A detailed presentation of the role of H" and Pi in the contractile process has been presented in the section on fatigue in isolated fibers. 

Harris, R.C., Sahlin, K., Hultman. E. (1977). Phosphagen and lactate contents of m. quadriceps femoris of man after exercise. J. Appl. Physiol. 43. 852-857. 

Karlsson, J. Saltin, B. (1970). Lactate. ATP, and CP in working muscles during exhaustive exercise in man. J. Appl. Physiol. 29, 598-602. 

A knowledge of normal metabohsm is essential for an understanding of abnormalities underlying disease. Normal metabolism includes adaptation to periods of starvation, exercise, pregnancy, and lactation. Abnormal metabolism may result from nutritional deficiency, enzyme deficiency, abnormal secretion of hormones, or the actions of drugs and toxins. An important example of a metabolic disease is diabetes mellitus. 

Lactate is the end product of glycolysis under anaerobic conditions (eg, in exercising muscle) or when the metabolic machinery is absent for the further oxidation of pyruvate (eg, in erythrocytes). 

TypeV Myophosphorylase deficiency, McArdle s syndrome Absence of muscle phosphorylase Diminished exercise tolerance muscles have abnormally high glycogen content (2.5-4.1%). Little or no lactate in blood after exercise. 

McNaughton, L., Two levels of caffeine ingestion on blood lactate and free fatty acid responses during incremental exercise, Research Quarterly, 58, 255, 1987. 

Systemic Human >16 min Resp Cardio Metab 5 M 5 M 2 M 5 M (increased blood lactate during exercise) Bhambhani and Singh 1991... 

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