High rates of muscle glycogen resynthesis after exhaustive ex.

High rates of muscle glycogen resynthesis after exhaustive exercise w.
http://jap.physiology.org/cgi/content/abstract/105/1/7 J Appl Physiol 105: 7-13, 2008. First published May 8, 2008; doi:10.1152/japplphysiol.01121.2007
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High rates of muscle glycogen resynthesis after exhaustive exercise
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when carbohydrate is coingested with caffeine
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David J. Pedersen, Sarah J. Lessard, Vernon G. Coffey, Emmanuel G. Churchley, Andrew M. Wootton,
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They Ng, Matthew J. Watt, and John A. Hawley
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School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia Alert me if a correction is posted
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Submitted 18 October 2007 ; accepted in final form 30 April 2008 Services
We determined the effect of coingestion of caffeine (Caff) with carbohydrate (CHO) on rates of muscle Email this article to a friend
glycogen resynthesis during recovery from exhaustive exercise in seven trained subjects who completed two Similar articles in this journal
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experimental trials in a randomized, double-blind crossover design. The evening before an experiment subjects Alert me to new issues of the journal
performed intermittent exhaustive cycling and then consumed a low-CHO meal. The next morning subjects Download to citation manager
rode until volitional fatigue. On completion of this ride subjects consumed either CHO [4 g/kg body mass Google Scholar
(BM)] or the same amount of CHO + Caff (8 mg/kg BM) during 4 h of passive recovery. Muscle biopsies and Articles by Pedersen, D. J.
blood samples were taken at regular intervals throughout recovery. Muscle glycogen levels were similar at Articles by Hawley, J. A.
exhaustion [ 75 mmol/kg dry wt (dw)] and increased by a similar amount ( 80%) after 1 h of recovery (133 ± PubMed
37.8 vs. 149 ± 48 mmol/kg dw for CHO and Caff, respectively). After 4 h of recovery Caff resulted in higher PubMed Citation
glycogen accumulation (313 ± 69 vs. 234 ± 50 mmol/kg dw, P < 0.001). Accordingly, the overall rate of Articles by Pedersen, D. J.
Articles by Hawley, J. A.
resynthesis for the 4-h recovery period was 66% higher in Caff compared with CHO (57.7 ± 18.5 vs. 38.0 ± 7.7 mmol·kg dw–1·h–1, P < 0.05). After 1 h of recovery plasma Caff levels had increased to 31 ± 11 µM (P < 0.001) and at the end of the recovery reached 77 ± 11 µM (P < 0.001) with Caff. Phosphorylation of CaMKThr286 was similar after exercise and after 1 h of recovery, but after 4 h CaMKThr286 phosphorylation was higher in Caff than CHO (P < 0.05). Phosphorylation of AMP-activated protein kinase (AMPK)Thr172 and AktSer473 was similar for both treatments at all time points. We provide the first evidence that in trained subjects coingestion of large amounts of Caff (8 mg/kg BM) with CHO has an additive effect on rates of postexercise muscle glycogen accumulation compared Akt; AMP-activated protein kinase; Ca2+/calmodulin-dependent kinase Address for reprint requests and other correspondence: J. A. Hawley, School of Medical Sciences, RMIT Univ., PO Box 71, Bundoora 3083, Victoria,Australia (e-mail: john.hawley@rmit.edu.au)

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