Caffeine improved cycling trial performance in mentally fatigued cyclists, regardless of alterations in prefrontal cortex activation

Physiol Behav. 2019 May 15;204:41-48. doi: 10.1016/j.physbeh.2019.02.009. Epub 2019 Feb 10.

Abstract

Purpose: To verify whether caffeine (CAF) could increase the prefrontal cortex (PFC) activation and improve 20 km cycling time trial (TT20km) performance in mentally fatigued cyclists.

Methods: After preliminary TT20km, twelve recreational cyclists (VO2MAX of 58.9 ± 6.2 mL kg min-1) performed a familiarization with a cognitive test to induce mental fatigue (MF) and psychological scales. Thereafter, they performed: 2) a baseline TT20km; 3) a mentally fatigued TT20km (MF); 4 and 5) a mentally fatigued TT20km after CAF (MF + CAF) or placebo (MF + PLA) ingestion, in a double-blind, counterbalanced design. Performance and psychological responses were obtained throughout the TT20km, while PFC electroencephalography (EEG) theta wave was obtained before and after the mental fatigue test.

Results: The mental fatigue-induced increase in EEG theta wave (↑ ~ 4.8%) was reverted with CAF (↓ 8.8%) and PLA ingestion (↓ 4.8%). CAF improved TT20km performance in mentally fatigued cyclists by reducing time (p = .00; ↓ ~ 1.7%) and increasing WMEAN (p = .00; ↑ ~ 3.6%), when compared to MF + PLA. The RPE-power output ratio was lower (p = .01), but affect (p = .018), motivation (p = .033) and emotional arousal (p = .001) were greater throughout the TT20km in MF + CAF than in MF + PLA.

Conclusions: CAF ingestion improved TT20km performance and psychological responses in mentally fatigued cyclists, despite the unaltered PFC activation.

Keywords: Fatigue; Pacing; Placebo; RPE; Supplementation.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arousal / drug effects
  • Athletic Performance*
  • Bicycling*
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Cognition / drug effects
  • Double-Blind Method
  • Electroencephalography / drug effects
  • Humans
  • Male
  • Mental Fatigue / drug therapy*
  • Mental Fatigue / psychology*
  • Motivation / drug effects
  • Physical Endurance
  • Prefrontal Cortex / drug effects*
  • Theta Rhythm / drug effects

Substances

  • Central Nervous System Stimulants
  • Caffeine