Exercise in the fasted state facilitates fibre type‐specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans

• DOI: 10.1113/jphysiol.2005.083170
• Publication Date: 2005-02-11T01:17:45Z
• Authors: K. De Bock; E. A. Richter; A. P. Russell; B. O. Eijnde; W. Derave; M. Ramaekers; E. Koninckx; B. Léger; J. Verhaeghe; P. Hespel
• Keywords: Vastus lateralis muscle; Exercise physiology

The effects were compared of exercise in the fasted state and with a high rate carbohydrate intake on intramyocellular triglyceride (IMTG) glycogen content human muscle. Using randomized crossover study design, nine young healthy volunteers participated two experimental sessions an interval 3 weeks. In each session subjects performed 2 h constant-load bicycle ( approximately 75% ), followed by 4 controlled recovery. On one occasion they exercised after overnight fast (F), other (CHO) received carbohydrates before 150 g) during (1 g (kg bw)(-1) h(-1)) exercise. both conditions, ingested 5 per kg body weight Fibre type-specific relative IMTG was determined Oil red O staining needle biopsies from m. vastus lateralis before, immediately During F but not CHO, bout decreased type I fibres 18 +/- 2% to 6 (P = 0.007) area lipid staining. Conversely, recovery, 15 10 did change F. Neither nor recovery changed IIa any condition. Exercise-induced net breakdown similar CHO. However, CHO (11.0 7.8 mmol kg(-1) h(-1)), mean postexercise muscle resynthesis 3-fold greater (32.9 2.7 h(-1), P 0.01). Furthermore, oral glucose loading increased plasma insulin markedly more (+46.80 microU ml(-1)) than (+14.63 ml(-1), 0.02). We conclude that prolonged submaximal takes place predominantly this is prevented CHO-fed state. facilitated glucose-induced secretion may contribute enhanced following