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Med Sci Sports Exerc. 2009 Sep;41(9):1744-51. doi: 10.1249/MSS.0b013e3181a16cf7.

Caffeine, cycling performance, and exogenous CHO oxidation: a dose-response study.

Author information

1
School of Public Health, Griffith University, Queensland, Australia. b.desbrow@griffith.edu.au

Abstract

PURPOSE:

This study investigated the effects of a low and moderate caffeine dose on exogenous CHO oxidation and endurance-exercise performance.

METHODS:

Nine trained and familiarized male cyclists (mean +/- SD: 29.4 +/- 4.5 yr, 81.3 +/- 10.8 kg body weight [BW], 183.8 +/- 8.2 cm, V O2peak = 61.7 +/- 4.8 mL.kg.min) undertook three trials, with training and high CHO diet being controlled. One hour before exercise, subjects ingested capsules containing placebo and 1.5 or 3 mg.kg BW of caffeine using a double-blind administration protocol. Trials consisted of 120 min steady-state cycling at approximately 70% V O2peak, immediately followed by a 7-kJ.kg BW time trial (TT). During exercise, subjects were provided with fluids containing C-glucose every 20 min to determine exogenous CHO oxidation.

RESULTS:

No significant TT performance improvements were observed during caffeine-containing trials (mean +/- SD: placebo = 30 min 25 s +/- 3 min 10 s; 1.5 mg.kg BW = 30 min 42 s +/- 3 min 41 s; and 3 mg.kg BW = 29 min 51 s +/- 3 min 38 s). Furthermore, caffeine failed to significantly alter maximal exogenous CHO oxidation (maximal oxidation rates: placebo = 0.95 +/- 0.2 g.min; 1.5 mg.kg BW = 0.92 +/- 0.2 g.min; and 3 mg.kg BW = 0.96 +/- 0.2 g.min).

CONCLUSION:

Low and moderate doses of caffeine have failed to improve endurance performance in fed, trained subjects.

PMID:
19657295
DOI:
10.1249/MSS.0b013e3181a16cf7
[Indexed for MEDLINE]

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