Caffeine, exercise physiology, and time-trial performance: no effect of <i>ADORA2A</i> or <i>CYP1A2</i> genotypes

The aim of this study was to investigate the influence ADORA2A and CYP1A2 genotypes on physiological ergogenic effects caffeine. Sixty-six male cyclists were screened for genotypes; with 40 taking part subsequently in a randomised, double-blind, placebo-controlled study. Trial 1 used establish oxygen uptake?power output relationship maximal uptake. In trials 2 3, participants ingested 5 mg·kg ?1 caffeine or placebo h before completing submaximal incremental cycling test, followed by time-trial (?30 min). Relative placebo, led significant reduction time complete (caffeine: 29.7 ± 1.8 min; placebo: 30.8 2.3 min); but there no effect genotype. During exercise, reduced mean heart rate 2.9 3.7 beats·min , dissipating as exercise intensity increased. Caffeine also significantly perceived exertion 0.5 0.8, increased blood lactate 0.29 0.42 mmol·L respiratory exchange ratio 0.013 0.032, minute ventilation 3.1 6.8 L·min . Nonetheless, supplement × genotype interactions. conclusion, influences responses improves performance irrespective genotypes. Novelty: affects at rest during independent Variability is not explained