Author Identifier (ORCID)
Abstract
This study examined the effects of caffeine consumption on endurance exercise performance, and the influence of CYP1A2 gene polymorphisms in caffeine pharmacokinetics and exercise performance. The data sets of two randomised, double blind, placebo-controlled crossover study design experiments have been merged. Thirty-eight recreationally active male participants provided saliva samples for CYP1A2 genotyping (AA homozygotes n = 19; AC heterozygotes n = 19) and completed either a 10-km run or 40-km cycling time trial of 60-min following a single dose of 6 mg·kg−1 caffeine (CAF) or placebo (maltodextrin; PLA) throughout which heart rate (HR) and time to completion (TTC) were measured. Caffeine ingestion improved TTC by 1.8% (p = 0.05; ηp2 = 0.12). HR was higher in CAF trials compared to PLA (p = 0.02; ηp2 = 0.15). Plasma caffeine concentrations were higher in AA allele carriers compared with AC allele carriers (p = 0.04; ηp2 = 0.139). No caffeine–gene interaction effects were observed in TTC, HR or plasma concentrations of paraxanthine and theophylline. Total caffeine plasma concentrations in the area under the concentration–time curve (AUC) were significantly higher in AA allele carriers compared with AC allele carriers (p = 0.01). Ingesting a dose of 6 mg·kg−1 caffeine 60-min prior to exercise is likely to improve performance in endurance activities in recreationally trained males. Plasma caffeine concentrations were significantly higher in AA allele carriers compared to AC allele carriers, though no gene–caffeine interaction main effects were observed in TTC; so, the role of CYP1A2 gene polymorphisms in determining enhancements in exercise performance remains unclear.
Keywords
athlete, endurance exercise, genetics, physical activity, sport
Document Type
Journal Article
Date of Publication
7-1-2026
Article Number
e70203
ISSN
17461391
Volume
26
Issue
7
PubMed ID
42230302
Publication Title
European Journal of Sport Science
Publisher
Wiley
School
School of Medical and Health Sciences
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Masters, C., Ali, A., Badenhorst, C., Dickens, M., & Rutherfurd‐Markwick, K. (2026). The effect of CYP1A2 gene polymorphisms on caffeine pharmacokinetics and exercise performance in male recreational athletes. European Journal of Sport Science, 26(7), Article e70203. https://doi.org/10.1002/ejsc.70203