Forskning

November 12, 2020

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

M Glaister et al, Caffeine, exercise physiology, and time-trial performance: no effect of ADORA2A or CYP1A2 genotypes, Applied Physiology Nutrition Metabolism, published online.

ABSTRACT:

The aim of this study was to investigate the influence of ADORA2A and CYP1A2 genotypes on the physiological and ergogenic effects of caffeine. Sixty-six male cyclists were screened for ADORA2A and CYP1A2 genotypes; with 40 taking part subsequently in a randomised, double-blind, placebo-controlled study. Trial 1 was used to establish the V̇O2-power output relationship and V̇O2max. In trials 2 and 3, participants ingested 5 mg·kg-1 of caffeine or placebo one hour before completing a submaximal incremental cycling test, followed by a time-trial (~ 30 mins). Relative to placebo, caffeine led to a significant reduction in time to complete the time-trial (caffeine: 29.7 ± 1.8 mins; placebo: 30.8 ± 2.3 mins); but there was no effect of genotype. During submaximal exercise, caffeine reduced mean heart rate by 2.9 ± 3.7 b·min-1, with effects dissipating as exercise intensity increased. Caffeine also significantly reduced perceived exertion by 0.5 ± 0.8, and increased blood lactate by 0.29 ± 0.42 mmol·L-1, respiratory exchange ratio by 0.013 ± 0.032, and minute ventilation by 3.1 ± 6.8 L·min-1. Nonetheless, there were no supplement × genotype interactions. In conclusion, caffeine influences physiological responses to submaximal exercise and improves time-trial performance irrespective of ADORA2A or CYP1A2 genotypes. Novelty •Caffeine affects physiological responses at rest and during submaximal exercise independent of ADORA2A or CYP1A2 genotypes. •Variability in the effect of caffeine on time-trial performance is not explained by ADORA2A or CYP1A2 genotypes.