Effects of caffeine on neuromuscular fatigue and performance during high-intensity cycling exercise in moderate hypoxia

Eur J Appl Physiol. 2017 Jan;117(1):27-38. doi: 10.1007/s00421-016-3496-6. Epub 2016 Nov 18.


Purpose: To investigate the effects of caffeine on performance, neuromuscular fatigue and perception of effort during high-intensity cycling exercise in moderate hypoxia.

Methods: Seven adult male participants firstly underwent an incremental exercise test on a cycle ergometer in conditions of acute normobaric hypoxia (fraction inspired oxygen = 0.15) to establish peak power output (PPO). In the following two visits, they performed a time to exhaustion test (78 ± 3% PPO) in the same hypoxic conditions after caffeine ingestion (4 mg kg-1) and one after placebo ingestion in a double-blind, randomized, counterbalanced cross-over design.

Results: Caffeine significantly improved time to exhaustion by 12%. A significant decrease in subjective fatigue was found after caffeine consumption. Perception of effort and surface electromyographic signal amplitude of the vastus lateralis were lower and heart rate was higher in the caffeine condition when compared to placebo. However, caffeine did not reduce the peripheral and central fatigue induced by high-intensity cycling exercise in moderate hypoxia.

Conclusion: The caffeine-induced improvement in time to exhaustion during high-intensity cycling exercise in moderate hypoxia seems to be mediated by a reduction in perception of effort, which occurs despite no reduction in neuromuscular fatigue.

Keywords: Altitude; Central fatigue; Exercise performance; Perception of effort; Peripheral fatigue.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Athletic Performance*
  • Caffeine / administration & dosage
  • Caffeine / adverse effects
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / administration & dosage
  • Central Nervous System Stimulants / adverse effects
  • Central Nervous System Stimulants / pharmacology*
  • Exercise*
  • Humans
  • Hypoxia / metabolism*
  • Male
  • Muscle Fatigue / drug effects*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology


  • Central Nervous System Stimulants
  • Caffeine