Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes

Guest, Nanci S.; Corey, Paul; Vescovi, Jason D.; El‐Sohemy, Ahmed

doi:10.1249/mss.0000000000001596

Cited by 142 publications

(176 citation statements)

References 36 publications

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“…The current investigation found a significant learning effect; however, it is possible that participants 2, 3,8,9,10,11,12,15,17,18,19, and 20 may have been "non-responders" to caffeine supplementation (see Table 1). The inter-individual differences in the ergogenicity of caffeine are thought to be related to genetic polymorphisms associated with the CYP1A2 and ADORA2A genes, which discern fast and slow caffeine metabolism/clearance [49,50]. The CYP1A2 gene, which codes for enzymes responsible for 95% of caffeine metabolism, is associated with "non-responders" to caffeine supplementation and is carried by 46% of the general population, a proportion similar to the 60% of "non-responders" in the current investigation.…”

Section: Discussionmentioning

confidence: 99%

Acute Caffeine Supplementation Does Not Improve Performance in Trained CrossFit® Athletes

Stein

Ramirez

Heinrich

2020

Sports

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Caffeine's ergogenic effects persist during various exercise modalities; however, information establishing its efficacy during CrossFit ® protocols is limited. This study aimed to determine the effects of caffeine supplementation on CrossFit ® performance. Twenty CrossFit ® -trained men (age = 26.7 ± 6.2 years, experience = 3.7 ± 2.9 years) were randomized in a double-blind, crossover design. Participants completed two sessions separated by a seven-day washout period, 60 min after consuming 5 mg/kg body mass of caffeine or a placebo. In each session, participants completed as many rounds as possible in 20 min of five pull-ups, 10 push-ups, and 15 air squats. CrossFit ® performance was the total number of repetitions completed in 20 min. Paired-samples t-tests were used to compare CrossFit ® performance between caffeine and placebo conditions and to test for a potential learning effect between the first and second sessions. CrossFit ® performance was not significantly different during the caffeine condition compared to the placebo (468.6 ± 114.7 vs. 466.7 ± 94.3 repetitions, p = 0.861). A significant learning effect was identified between the first and second sessions (452.4 ± 101 vs. 483.8 ± 106.5 repetitions, p = 0.001), with no significant effect of treatment order (p = 0.438). Caffeine's ergogenic effect were not present during the CrossFit ® workout "Cindy"; however, future research should include familiarization sessions and examine other CrossFit ® workouts in novice and women participants.

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Section: Discussionmentioning

confidence: 99%

Acute Caffeine Supplementation Does Not Improve Performance in Trained CrossFit® Athletes

Stein

Ramirez

Heinrich

2020

Sports

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“…3 There is also some evidence that the effect of caffeine on time trial performance may be influenced by a genetic factor. 28,34,35,51,[65][66][67] Research to date has focused on the CYP1A2 gene that influences the rate at which the liver metabolizes caffeine, and the ADORA2A gene that, through its influence on A2A receptor binding characteristics, influences dopaminergic neurotransmission. 65,67 Results so far have been equivocal, possibly due to methodological inconsistencies.…”

Section: Discussionmentioning

confidence: 99%

Effects of Caffeine on Time Trial Performance and Associated Physiological Responses: A Meta-Analysis

GlaisterMark

MoirGavin

2019

Journal of Caffeine and Adenosine Research

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Background: The aim of this study was to conduct a systematic review and meta-analysis on the effects of caffeine supplementation on time trial performance and associated physiological responses. Methods: A total of 35 studies met the inclusion criteria of adopting double-blind randomized placebocontrolled crossover designs that included a closed-loop time trial ( ‡5 minutes) performed under a caffeine dose of 3-6 mg/kg administered 30-90 minutes beforehand. Meta-analyses were completed using a random-effects model, with effects on time trial performance presented as standardized mean difference (d) and with physiological responses presented as raw mean difference (D). The 95% confidence limits (CL 95 ) were calculated for all estimates. Results: Relative to placebo, caffeine had a positive effect on time trial performance (d = 0.32; CL 95 [0.19-0.44]). Moreover, the effect of caffeine on time trial performance corresponded with increases in heart rate (D = 3.3 beats/min; CL 95 [1.7-4.8]), oxygen uptake (D = 0.09 L/min; CL 95 [0.02-0.17]), blood lactate (D = 1.42 mmol/L; CL 95 [1.09-1.74]), and blood glucose (D = 0.94 mmol/L; CL 95 [0.58-1.30]). In contrast, caffeine had no effect on time trial measures of respiratory exchange ratio (D = 0.01; CL 95 [À0.01 to 0.02]), or ratings of perceived exertion (D = 0.1; CL 95 [À0.1 to 0.3]). Conclusions:The results reveal a clear effect of caffeine on moderate-to high-intensity time trial performance. When considered in conjunction with research using fixed-intensity exercise, the caffeine-induced increase in time trial intensity likely explains all of the associated increases in heart rate and oxygen uptake, and part of the increase in blood lactate and blood glucose.

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“…Individuals with the AA genotype at rs762551 are commonly classified as "fast caffeine metabolizers", while C allele carriers (AC/CC genotypes) tend to have a slower clearance of caffeine and are, therefore, commonly classified as "slow caffeine metabolizers" [9]. Significantly greater ergogenic effects of caffeine on aerobic endurance have been reported for individuals with the AA genotype, compared with C allele carriers [6,10]. However, for high-intensity exercise tasks of a shorter duration, the evidence is less clear.…”

Section: Introductionmentioning

confidence: 99%

CYP1A2 genotype and acute effects of caffeine on resistance exercise, jumping, and sprinting performance

Grgić

Pickering

Bishop

et al. 2020

Journal of the International Society of Sports Nutrition

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Background: It has been suggested that polymorphisms within CYP1A2 impact inter-individual variation in the response to caffeine. The purpose of this study was to explore the acute effects of caffeine on resistance exercise, jumping, and sprinting performance in a sample of resistance-trained men, and to examine the influence of genetic variation of CYP1A2 (rs762551) on the individual variation in responses to caffeine ingestion.Methods: Twenty-two men were included as participants (AA homozygotes n = 13; C-allele carriers n = 9) and were tested after the ingestion of caffeine (3 mg/kg of body mass) and a placebo. Exercise performance was assessed with the following outcomes: (a) movement velocity and power output in the bench press exercise with loads of 25, 50, 75, and 90% of one-repetition maximum (1RM); (b) quality and quantity of performed repetitions in the bench press exercise performed to muscular failure with 85% 1RM; (c) vertical jump height in a countermovement jump test; and (d) power output in a Wingate test.Results: Compared to placebo, caffeine ingestion enhanced: (a) movement velocity and power output across all loads (effect size [ES]: 0.20-0.61; p < 0.05 for all); (b) the quality and quantity of performed repetitions with 85% of 1RM (ES: 0.27-0.85; p < 0.001 for all); (c) vertical jump height (ES: 0.15; p = 0.017); and (d) power output in the Wingate test (ES: 0.33-0.44; p < 0.05 for all). We did not find a significant genotype × caffeine interaction effect (pvalues ranged from 0.094 to 0.994) in any of the analyzed performance outcomes.Conclusions: Resistance-trained men may experience acute improvements in resistance exercise, jumping, and sprinting performance following the ingestion of caffeine. The comparisons of the effects of caffeine on exercise performance between individuals with the AA genotype and AC/CC genotypes found no significant differences.

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Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes

Cited by 142 publications

References 36 publications

Acute Caffeine Supplementation Does Not Improve Performance in Trained CrossFit® Athletes

Acute Caffeine Supplementation Does Not Improve Performance in Trained CrossFit® Athletes

Effects of Caffeine on Time Trial Performance and Associated Physiological Responses: A Meta-Analysis

CYP1A2 genotype and acute effects of caffeine on resistance exercise, jumping, and sprinting performance

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