Exercise metabolic adaptation

McGilvery, R.W. (1975). The use of fuels for muscular work. In Metabolic Adaptations to Prolonged Physical Exercise (Howald, H. Poortmans, J.R., eds.), pp. 12-30, Birkhauser Verlag, Basel. 

The transition from rest to mild activity and then to strenuous activity provides us with a good example of metabolism adapting to changes in the physiological situation. Exercise-related biochemistry is a major subject of research and a detailed description is beyond the scope of this text and the interested reader is referred to a specialized source. A brief overview is given below. 

Fig. 47.11. Production of blood glucose by the liver from various precursors during rest and during prolonged exercise. The shaded area represents the contribution of liver glycogen to blood glucose, and the open area represents the contribution of gluconeogenesis. From Wahren J, et al. In Howald H, Poortmans JR, eds. Metabolic Adaptation to Prolonged Physical Exercise. Cambridge, MA Birkhauser, 1973 148.

Interdependence of AMPK and SIRTl for metabolic adaptation to fasting and exercise in skeletal muscle. Cell Metab 11 213-219... 

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. 

As is often the case, tissue-specific control mechanisms operate to optimise adaptation to particular conditions. For example, muscle contraction requires an increase in cytosolic calcium ion concentration (see Section 7.2.1, Figure 7.4). During exercise when energy generation needs to be increased, or from a more accurate metabolic point of view, when the ATP-to-ADP ratio falls rapidly, and the accompanying rise in [Ca2 + ] activate (i) glycogen phosphorylase which initates catabolism of... 

For completion of the discussion it is useful to remind the reader that the delivery of 02 to working muscles, and the extraction of 02 by working muscles, must be closely integrated with the metabolic adjustments described above. That indeed is the case, and it is of course well known that aerobic training induces an adaptive increase in the maximum cardiac output and thus in the total amount and total rate of 02 delivered to muscle. Although in theory the delivery of 02 to muscles could also be increased by preferential perfusion (i.e., redistribution of cardiac output), this mechanism does not appear to be utilized. So the question arises Does the increase in cardiac output during aerobic exercise proceed in step with the overall increase in maximum 02 uptake rates The answer turns out to be negative. 

L. D., ed.), pp. 555-631, Am. Physiol. Soc., Bethesda, MD. Holloszy, J. 0. and Coyle, E. F. (1984) Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. J. Appl. Physiol. Resplrat. Environ. Exercise Physiol. 56 831-8. 

SO. Henrlksson, J. (1977) Training Induced adaptations of skeletal muscle and metabolism during submaxlmal exercise. J. Physiol. 270 661-75. 

Holloszy, J.O. and Coyle, E.F. (1984) Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. J. Appl. Physiol. 5b S31-6Jo. 

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