Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation

Lívia de Souza Gonçalves, Vitor de Salles Painelli, Guilherme Yamaguchi, Luana Farias de Oliveira, Bryan Saunders, Rafael Pires da Silva, Erika Maciel, Guilherme Giannini Artioli, Hamilton Roschel, Bruno Gualano

To investigate the influence of habitual caffeine intake on exercise performance to acute caffeine supplementation. A double-blind, crossover, counterbalanced study was performed. Forty endurance-trained cyclists were allocated into tertiles according to their daily caffeine intake: low (58 ± 29 mg(.)d(-1)), moderate (143 ± 25 mg(.)d(-1)), and high consumers (351 ± 139 mg(.)d(-1)). Participants completed three trials in which they performed simulated cycling time-trials in the fastest time possible following ingestion of: caffeine (CAF: 6 mg(.)kg(-1) BM), placebo (PLA), and no supplement (CON). Mixed-model analysis revealed time-trial performance was significantly improved in CAF compared to PLA and CON (29.92±2.18 min vs 30.81±2.67 and 31.14±2.71 min; P = <0.0002). ANCOVA revealed no influence of habitual caffeine intake as a covariate on exercise performance (P=0.47). Time-trial performance was not significantly different between tertiles (P=0.75). No correlation was observed between habitual caffeine intake and absolute changes (CAF - CON) in time-trial performance with caffeine (P=0.524). Individual analysis showed that eight, seven and five individuals improved above the variation of the test in CAF in the low, moderate and high tertiles. A Fisher's Exact Test did not show any significant differences in the number of individuals who improved in CAF between the tertiles (P>0.05). Blood lactate and ratings of perceived exertion were not different between trials and tertiles (P>0.05). Performance effects of acute caffeine supplementation during a ~30 min cycling TT performance were not influenced by the level of habitual caffeine consumption.