Ergogenic effects of low doses of caffeine on cycling performance

Int J Sport Nutr Exerc Metab. 2008 Jun;18(3):328-42. doi: 10.1123/ijsnem.18.3.328.

Abstract

The purpose of this experiment was to learn whether low doses of caffeine have ergogenic, perceptual, and metabolic effects during cycling. To determine the effects of 1, 2, and 3 mg/kg caffeine on cycling performance, differentiated ratings of perceived exertion (D-RPE), quadriceps pain intensity, and metabolic responses to cycling exercise, 13 cyclists exercised on a stationary ergometer for 15 min at 80% VO, then, after 4 min of active recovery, completed a 15-min VO2peak performance ride 60 min after ingesting caffeine or placebo. Work done (kJ/kg) during the performance ride was used as a measure of performance. D-RPE, pain ratings, and expired-gas data were obtained every 3 min, and blood lactate concentrations were obtained at 15 and 30 min. Compared with placebo, caffeine doses of 2 and 3 mg/kg increased performance by 4% (95% CI: 1.0-6.8%, p = .02) and 3% (95% CI: -0.4% to 6.8%, p = .077), respectively. These effects were ergogenic, on average, but varied considerably in magnitude among individual cyclists. There were no effects of caffeine on D-RPE or pain throughout the cycling task. Selected metabolic variables were affected by caffeine, consistent with its known actions. The authors conclude that caffeine preparations of 2 and 3 mg/kg enhanced performance, but future work should aim to explain the considerable interindividual variability of the drug's ergogenic properties.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Bicycling / physiology*
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Exercise Test
  • Fatigue
  • Humans
  • Lactates / blood
  • Male
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / innervation
  • Nociceptors / drug effects
  • Nociceptors / physiology
  • Oxygen Consumption / drug effects
  • Pain / drug therapy
  • Pain / etiology
  • Pain Measurement
  • Pain Threshold
  • Perception
  • Physical Exertion / drug effects*
  • Physical Exertion / physiology
  • Time Factors
  • Treatment Outcome

Substances

  • Central Nervous System Stimulants
  • Lactates
  • Caffeine