Abstract: Objective To observe the effects of 8-week aerobic exercise on skeletal muscle glycogen content and exercise endurance and investigate the possible mechanism in rats with chronic heart failure. Methods 30 Sprague-Dawley rats were submitted to heart failure sedentary (H) group, heart failure traning (HT) group and sham operation (S) group. The heart failure model was established with coronary artery ligation. HT group performed an 8-week treadmill running. The skeletal muscle glycogen content was determined with anthracenone, exercise endurance with exhaust duration of graded exhausted exercise test, glucose uptake rate, activity of glycogen synthase (GS) and glycogen phosphorylase (GP) with radicisotope, protein expression of total GS, phospho-GS (p-GS), total GP and phospho-GP (p-GP) with Western Blotting. Correlation analysis was conducted between glycogen content and exhaust duration. Results The skeletal muscle glycogen, exhaust duration, glucose uptake rate, GS activity and p-GP protein reduced (P<0.05), while serum insulin, GP activity and p-GS protein raised (P<0.05) in the H group compared with those in the S group. The skeletal muscle glycogen, exhaust duration, glucose uptake rate, GS activity and p-GP protein increased (P<0.05), while serum insulin, GP activity and p-GS protein decreased (P<0.05) in the HT group compared with those in the H group. There was positive correlation between glycogen content and exhaust duration (P<0.05). Conclusion Prolonged aerobic exercise enhanced skeletal muscle glycogen content and exercise endurance in rats with chronic heart failure, which may be related to the improvement of insulin sensitivity, muscle glucose uptake, increase of glycogen synthesis and decrease of glycogen breakdown.

Key words: heart failure, aerobic exercise, skeletal muscle, glycogen, exercise endurance, rat