Caffeine influences cadence at lower but not higher intensity RPE-regulated cycling

Caffeine blunts RPE estimations but effects on selected cycling cadence are unclear.

This study examined influence of caffeine on cycling cadence with intensities prescribed at RPE 4 and 7 (OMNI Scale).

College-aged (20.5±2.0y) male and female volunteers (n=15) (VO₂ peak=40.3±4.0,) completed a maximal cycling test followed by trials where they adjusted cadence (CAD) (clamped resistances) to produce overall feelings equivalent to RPE 4 (RPE4) and RPE 7 (RPE7) (10min each) following caffeine (CAF) (6mg·kg^-1·min^-1) and placebo (PLA) (counterbalanced) ingestion. Participants were blinded to cadence during production trials.

Repeated measures ANOVA showed a significant main effect (trial) for CAD (CAF ~4rev·min^-1 faster) for RPE4 but no significance for RPE7. Main effect for heart rate (HR) was not significant for RPE4 but significant for RPE7 (CAF ~4b·min^-1 higher). Main effects showed mean VO₂ significantly higher (~1.5-2ml·kg^-1·min^-1) for CAF for RPE4 and RPE7. Using a calculated least significant difference (5rev·min^-1) positive responses were observed for five individuals (33%) for RPE4 and 3 individuals (20%) for RPE7. No negative (significantly slower cadences) responses were observed. RER in select trials suggested increased reliance on free fatty acid for CAF in responders.

Mean results show a mild effect of CAF on cadence selection during RPE production. However, assessing individual results more effectively clarifies ergogenic responses. Future research should identify factors responsible for diverse responses to caffeine during exercise.