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CYCLING PERFORMANCE TIPS

  Last updated: 6/25/2012

High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine.

J Appl Physiol. 2008 Jul;105(1):7-13. Epub 2008 May 8

Pedersen DJ, Lessard SJ, Coffey VG, Churchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA.

School of Medical Sciences, RMIT University, Bundoora 3083, Victoria, Australia

We determined the effect of coingestion of caffeine (Caff) with carbohydrate (CHO) on rates of muscle glycogen resynthesis during recovery from exhaustive exercise in seven trained subjects who completed two experimental trials in a randomized, double-blind crossover design. The evening before an experiment subjects performed intermittent exhaustive cycling and then consumed a low-CHO meal. The next morning subjects rode until volitional fatigue. On completion of this ride subjects consumed either CHO [4 g/kg body mass (BM)] or the same amount of CHO + Caff (8 mg/kg BM*) during 4 h of passive recovery. Muscle biopsies and blood samples were taken at regular intervals throughout recovery. Muscle glycogen levels were similar at exhaustion [ approximately 75 mmol/kg dry wt (dw)] and increased by a similar amount ( approximately 80%) after 1 h of recovery (133 +/- 37.8 vs. 149 +/- 48 mmol/kg dw for CHO and Caff, respectively). After 4 h of recovery Caff resulted in higher glycogen accumulation (313 +/- 69 vs. 234 +/- 50 mmol/kg dw, P < 0.001). Accordingly, the overall rate of 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 x kg dw(-1) x h(-1), P < 0.05). After 1 h of recovery plasma Caff levels had increased to 31 +/- 11 microM (P < 0.001) and at the end of the recovery reached 77 +/- 11 microM (P < 0.001) with Caff. Phosphorylation of CaMK(Thr286) was similar after exercise and after 1 h of recovery, but after 4 h CaMK(Thr286) phosphorylation was higher in Caff than CHO (P < 0.05). Phosphorylation of AMP-activated protein kinase (AMPK)(Thr172) and Akt(Ser473) 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 with consumption of CHO alone.


* As a frame of reference, 8 mg of caffeine per kg body wieght for a 70 kg (150 pound cyclist is 540 mg.

A 7 oz cup of coffee has the following caffeine (mg) amounts, according to Bunker and McWilliams in J. Am. Diet. 74:28-32, 1979:

7oz coffee:

Coca-Cola Classic contains 2.83 mgs of caffeine per fluid ounce (or about 36 mg in a 12 ounce can)


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