Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans De Bock, K., Richter, E. A., Russell, Aaron, Eijnde, B. O., Derave, W., Ramaekers, M., Konickz, E., Leger, B., Verhaeghe, J. and Hespel, P. 2005, Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans, Journal of applied physiology, vol. 564, no. 2, pp. 649-660, doi: 10.1113/jphysiol.2005.083170. Attached Files Name Description MIMEType Size Downloads Title Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans Author(s) De Bock, K. Richter, E. A. Russell, Aaron orcid.org/0000-0002-7323-9501 Eijnde, B. O. Derave, W. Ramaekers, M. Konickz, E. Leger, B. Verhaeghe, J. Hespel, P. Journal name Journal of applied physiology Volume number 564 Issue number 2 Start page 649 End page 660 Publisher American Physiological society Place of publication Bethesda, Md. Publication date 2005 ISSN 8750-7587 1522-1601 Keyword(s) dietary carbohydrates fasting triglycerides insulin release lipid degradation Summary The effects were compared of exercise in the fasted state and exercise with a high rate of carbohydrate intake on intramyocellular triglyceride (IMTG) and glycogen content of human muscle. Using a randomized crossover study design, nine young healthy volunteers participated in two experimental sessions with an interval of 3 weeks. In each session subjects performed 2 h of constant-load bicycle exercise (∼75% VO2max ), followed by 4 h of controlled recovery. On one occasion they exercised after an overnight fast (F), and on the other (CHO) they received carbohydrates before (∼150 g) and during (1 g (kg bw)−1 h−1) exercise. In both conditions, subjects ingested 5 g carbohydrates per kg body weight during recovery. Fibre type-specific relative IMTG content was determined by Oil red O staining in needle biopsies from m. vastus lateralis before, immediately after and 4 h after exercise. During F but not during CHO, the exercise bout decreased IMTG content in type I fibres from 18 ± 2% to 6 ± 2% (P= 0.007) area lipid staining. Conversely, during recovery, IMTG in type I fibres decreased from 15 ± 2% to 10 ± 2% in CHO, but did not change in F. Neither exercise nor recovery changed IMTG in type IIa fibres in any experimental condition. Exercise-induced net glycogen breakdown was similar in F and CHO. However, compared with CHO (11.0 ± 7.8 mmol kg−1 h−1), mean rate of postexercise muscle glycogen resynthesis was 3-fold greater in F (32.9 ± 2.7 mmol kg−1 h−1, P= 0.01). Furthermore, oral glucose loading during recovery increased plasma insulin markedly more in F (+46.80 μU ml−1) than in CHO (+14.63 μU ml−1, P= 0.02). We conclude that IMTG breakdown during prolonged submaximal exercise in the fasted state takes place predominantly in type I fibres and that this breakdown is prevented in the CHO-fed state. Furthermore, facilitated glucose-induced insulin secretion may contribute to enhanced muscle glycogen resynthesis following exercise in the fasted state. Language eng DOI 10.1113/jphysiol.2005.083170 Field of Research 060199 Biochemistry and Cell Biology not elsewhere classified Socio Economic Objective 970106 Expanding Knowledge in the Biological Sciences HERDC Research category C1.1 Refereed article in a scholarly journal ERA Research output type C Journal article Copyright notice ©2005, The Physiological Society Persistent URL http://hdl.handle.net/10536/DRO/DU:30009121 Document type: Journal Article Collections: School of Exercise and Nutrition Sciences Centre for Physical Activity and Nutrition Research Related Links Link Description Connect to published version (restricted access) Go to link with your DU access privileges     Unless expressly stated otherwise, the copyright for items in DRO is owned by the author, with all rights reserved. Versions Version Filter Type Mon, 02 Feb 2009, 11:07:30 EST Mon, 19 Apr 2010, 16:13:26 EST Fri, 03 Feb 2012, 07:47:13 EST Thu, 26 Apr 2012, 15:33:38 EST Tue, 10 Dec 2013, 14:58:36 EST Mon, 16 Jun 2014, 09:58:43 EST Filtered Full Citation counts:   Cited 56 times in TR Web of Science Cited 67 times in Scopus Search Google Scholar Access Statistics: 680 Abstract Views, 0 File Downloads  -  Detailed Statistics Created: Mon, 13 Oct 2008, 15:51:44 EST

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