Time Course for Refilling of Glycogen Stores in Human Muscle Fibres Following Exercise‐Induced Glycogen Depletion

Abstract

PIEHL, K. T i m e course for refilling of glycogen stores in h u m a n muscle fibres following exercise-induced glycogen depletion. Acta physiol. scand. 1974. 90. 297- 302.Muscle biopsy samples were obtained from the thigh muscle of 4 subjects before and after 2 h of work and a t selected intervals during the following 46 h when a carbohydrate enriched diet was consumed. Mean glycogen content declined 103 (from 125 to 22) mmol glucose units x kg-l following exercise. 5 and 10 h after consuming the carbohydrate enriched diet muscle glycogen increased to 64 and 86 mmol glucose units X kg-l, respectively. During the first 5 h there was a marked storage of glycogen in the muscle which was related to the carbohydrate intake, but pre-exercise concentrations of muscle glycogen were observed first after 46 h. T h e increase in glycogen occurred in both fibre types, but the fast twitch fibres replinished their glycogen somewhat faster than did the slow twitch fibres suggesting a higher glycogen synthetase activity. At glycogen concentrations above 80-90 mmol no differences in the glycogen content of the two fibre types could be discerned with histochemical methods.

Reduced carbohydrate availability enhances exercise-induced p53 signaling in human skeletal muscle: implications for mitochondrial biogenesis

“…Indeed, the magnitude of elevation of Tfam in LOW compared with HIGH (i.e., ϳ1.5-fold differences) is consistent with time-course studies, which show significant increases between 4 and 24 h postexercise (37), which is similar to the time course of our depletion protocol given that our preexercise biopsy was sampled within 10 -12 h upon exercise completion. We deliberately chose not to include a glycogen depletion protocol in our HIGH trial, as the particular time scale (i.e., Ͻ12 h between the evening depletion protocol and the main trial on the subsequent morning) would not likely permit restoration of muscle glycogen to high levels (42), especially in our cohort of recreationally active males as opposed to endurance-trained subjects (19). Although we acknowledge that we could have included a depletion protocol in an earlier timescale (e.g., 24 -36 h prior to the main trial), adopting this design would have required the inclusion of an alternative nutritional strategy, such as high-fat or protein feeding, so as to provide appropriate energy intake and as such, would have introduced confounding variables, which would affect gene expression (38, 39).…”

Thermic effect of glucose in man. Obligatory and facultative thermogenesis.

“…In depleted muscles, glycogen repletion has been shown to be proportional to the carbohydrate content of subsequent meals (29), and a direct relationship between muscle glycogen synthase activity and the rate of glycogen synthesis during glucose/insulin infusions has been demonstrated (30,31,32). In the liver, Bishop et al (33) have shown by infusing glucose 6-'4C with insulin in dogs that almost all of the 14C that was recovered as liver glycogen was in the 6-C position (>90%), conditions, were to explain some or all of the observed increase in thermogenesis, then it is likely that they are also under the influence of sympathetic control, since almost all of the facultative thermic response could be suppressed by , 3 Tables I and II).…”

The athlete’s diet: nutritional goals and dietary strategies

“…(Nieman & Pedersen, 1999). Recovery of the muscle and liver glycogen stores after exercise is a rather slow process, and complete recovery may not be achieved until 24-48 h after the end of exercise (Piehl, 1974). The rate of glycogen resynthesis after exercise is determined largely by the amount of carbohydrate supplied by the diet (Ivy, 2000), and the amount of carbohydrate consumed is of far greater importance for this process than the type of carbohydrate.…”