Muscles exercised-produced catabolic

Mild exercise produced by swimming rats for one hour decreased protein synthesis by 17. While more intense treadmill running reduced synthesis by 30 and an exhaustive run of three hours inhibited synthesis by 70. These data suggest that exercise may produce a catabolic condition in muscles which would make amino acids available for oxidation and that this effect is dependent on the Intensity and duration of the exercise. 

Exercise is known to have acute catabolic effects on muscle protein turnover. During exercise protein snythesis is depressed which leads to protein catabolism. However, the impact of a relatively short exercise bout on 24-hour protein needs is unclear. Anaerobic exercise can produce hypertrophy of specific muscles depending on the type of training utilized. The hypertrophy is due to a positive balance in protein turnover which appears to be produced by an increase in the rate of protein synthesis after exercise. The increased need for protein during anaerobic exercise is unlikely to be more than 7 grams per day. 

The lactic acid that is produced is moved from the muscles through the blood to the liver. There, it is converted back into glucose that can be used in catabolic processes to yield more energy once oxygen becomes available. However, if lactic acid builds up in muscle cells at a faster rate than the blood can remove it, muscle fatigue results. Buildup of lactic acid is what causes a burning pain in the muscle during strenuous exercise. 

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