The effect of caffeine on cognitive performance is influenced by CYP1A2 but not ADORA2A genotype, yet neither genotype affects exercise performance in healthy adults

Abstract

Abstract Purpose To determine the influence of two commonly occurring genetic polymorphisms on exercise, cognitive performance, and caffeine metabolism, after caffeine ingestion. Methods Eighteen adults received caffeine or placebo (3 mg kg −1 ) in a randomised crossover study, with measures of endurance exercise (15-min cycling time trial; 70-min post-supplementation) and cognitive performance (psychomotor vigilance test; PVT; pre, 50 and 95-min post-supplementation). Serum caffeine and paraxanthine were measured (pre, 30 and 120-min post-supplementation), and polymorphisms in ADORA2A (rs5751876) and CYP1A2 (rs762551) genes analysed. Results Caffeine enhanced exercise performance ( P < 0.001), but effects were not different between participants with ADORA2A ‘high’ ( n = 11) vs. ‘low’ ( n = 7) sensitivity genotype (+ 6.4 ± 5.8 vs. + 8.2 ± 6.8%), or CYP1A2 ‘fast’ ( n = 10) vs. ‘slow’ ( n = 8) metabolism genotype (+ 7.2 ± 5.9 vs. + 7.0 ± 6.7%, P > 0.05). Caffeine enhanced PVT performance ( P < 0.01). The effect of caffeine was greater for CYP1A2 ‘fast’ vs. ‘slow’ metabolisers for reaction time during exercise (− 18 ± 9 vs. − 1.0 ± 11 ms); fastest 10% reaction time at rest (− 18 ± 11 vs. − 3 ± 15 ms) and lapses at rest (− 3.8 ± 2.7 vs. + 0.4 ± 0.9) ( P < 0.05). There were no PVT differences between ADORA2A genotypes ( P > 0.05). Serum caffeine and paraxanthine responses were not different between genotypes ( P > 0.05). Conclusion Caffeine enhanced CYP1A2 ‘fast’ metabolisers’ cognitive performance more than ‘slow’ metabolisers. No other between-genotype differences emerged for the effect of caffeine on exercise or cognitive performance, or metabolism.