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This study investigates the influence of habitual caffeine intake on aerobic exercise-performance responses to acute caffeine supplementation. A double-blind, crossover, counterbalanced study was performed. Forty male endurance-trained cyclists were allocated into tertiles, according to their daily caffeine intake: low (58±29 mg/d), moderate (143±25 mg/d), and high (351±139 mg/d) consumers. Participants completed three trials in which they performed simulated cycling time trials (TTs) in the fastest time possible following ingestion of the following: caffeine (CAF: 6 mg/kg body mass), placebo (PLA), and no supplement (CON). A mixed-model analysis revealed that TT performance was significantly improved in CAF compared with PLA and CON (29.92±2.18 vs. 30.81±2.67 and 31.14±2.71 min, respectively; P= 0.0002). Analysis of covariance revealed no influence of habitual caffeine intake as a covariate on …