Distribution of urine samples according to the concentration of caffeine in , , and LOD: limit of detection. Figure 3 depicts box-and-whisker plots for the changes in urine caffeine concentrations in , , and in men and women. Box-and-whisker plot for caffeine concentrations in the urine samples from men and women collected in , , and Figure 4 depicts urine caffeine concentration in Olympic sports in using box-and-whisker plots. Table 1 contains information on the changes in the median urine caffeine concentrations in Olympics sports for the years , , and Specifically, the values obtained in were significantly higher than those obtained in and in aquatics, athletics, boxing, judo, and football.
In golf and skiing, the data from were higher only when compared to , while in rowing and weightlifting, the values in were only different to Box-and-whisker plot for caffeine concentrations in the urine samples of Olympic sports collected in The purpose of this investigation was to describe the changes in urine caffeine concentration of samples obtained in competition of Olympic sports for the years , , and The final goal was to determine the evolution in the use of caffeine in sports, especially one decade after it was removed from the banned list.
The main outcomes of this investigation indicate the following: a in , there was a slight but statistically significant increase in urine caffeine concentration when compared to both and Sports such as aquatics, athletics, boxing, judo and weightlifting had a progressive increase in urine caffeine concentration from to , while the concentration in other Olympic sports remained stable throughout this period; c in , cycling, athletics, and rowing were the sports with the highest urine caffeine concentration, while shooting, basketball, and golf were the disciplines with the lowest concentrations of urinary caffeine.
All this information suggests that the use of caffeine in sports increased from to , particularly in some individual sports. However, the magnitude of the change in the urine caffeine concentrations obtained in competition does not reflect misuse of this substance in most sport disciplines.
After the removal of caffeine from the list of prohibited substances in , athletes were free to consume caffeine at any amount before, during or even after competitions without the burden of being sanctioned by the anti-doping authorities. In the first five years after this administrative decision, the urinary concentration of caffeine in sport did not significantly change, as was shown by the comparative values of the reports made before [ 27 ] and after [ 28 , 29 ]. The absence of change suggested a high but stable utilization of caffeine by athletes, with most of the samples in the low-to-middle range of urinary caffeine concentrations.
However, more than new studies dealing with the effects of caffeine in sports have appeared since , particularly original investigations determining the effects of caffeine on team sports, strength- and power-based sports or those with an intermittent nature. Besides, caffeine-containing products have become more accessible in all types of markets because of the conception of new supplements that incorporate caffeine in their formulation e.
Even so, the use of caffeine in sports competition has not dramatically changed since although a slight increase in is suggested by the changes in the distribution of urine caffeine concentration. First, the percentage of samples with a urine caffeine concentration below the limit of detection decreased from The omnipresence of caffeine in the diet means that this substance can be consumed by some athletes without the intention of increasing physical performance i.
Although there is no consensus about the urinary caffeine concentration that differentiates the social use of caffeine from the intentional use of caffeine to enhance performance, previous investigations have revealed that lower doses of caffeine that increase performance i. By using the cut-off point proposed by WADA, one might assume that caffeine abuse has remained constant and low in the last decade.
Interestingly, the increase in the concentration of caffeine has not been equally present in all sports. The mean urinary concentration of athletes tested in aquatics, athletics, boxing, judo, and weightlifting increased from to , suggesting a rise in the use of this substance among these particular sports. Other sports such as basketball, cycling, fencing, handball, hockey, shooting, and volleyball have maintained urine caffeine concentration at relatively stable values, suggestive of a steady-state use of caffeine in the last decade.
Despite the uneven evolution or urinary caffeine concentration from to among sports, the individual disciplines with an aerobic-based performance continue to be the sports with the highest concentrations of caffeine, while team sports and accuracy sports are the disciplines with the lowest concentrations of caffeine Figure 4. The higher urinary caffeine concentrations found in aerobic-based sports might be related to the traditional evidence that supported the ergogenic effects of caffeine by using laboratory-based research protocols with endurance-like exercise.
However, more recent evidences, obtained in sport-specific situations, have demonstrated that the beneficial effects of pre-competition caffeine intake is extended to sprint- and power-based exercise [ 5 , 38 ], team sports [ 6 , 39 , 40 ], combat sports [ 8 , 41 ] and sports in which accuracy is a key element for success [ 42 , 43 ]. With these new evidences, it might be expected a higher consumption of caffeine—and a higher urinary caffeine concentration—in these type of sport disciplines in the next years that should be investigated in future research.
The urinary concentration of caffeine has significantly increased in both male and female athletes since Figure 2 and median values reached 0. Although the median values for men and women are very comparable, the proportion of samples from women athletes at high urinary caffeine concentrations is higher than expected in comparison to the proportion of urine samples from male athletes. This is also supported by the similar urinary pharmacokinetic parameters found for male and female adults [ 44 ], which suggests that the higher urinary caffeine excretion in women is related to the ingestion of higher relative doses rather than differences in caffeine metabolism and excretion.
The current analysis presents some limitations that should be discussed to correctly understand the outcomes of the investigation. First, the analysis included data from urine caffeine concentration in three selected years , , and Thus, due to the high number of samples analyzed in the Madrid Doping Control Laboratory between and , we have been only able of obtaining the data of all urine samples, irrespective of their urinary caffeine concentration, in these three specific years.
Second, the urine samples included in the analysis were exclusively obtained in national and international competitions held in Spain. Although in these competitions participate athletes of different nationalities, it is expected that a high proportion of the samples analyzed pertained to Spanish athletes. Thus, it is still possible that the evolution of urinary caffeine concentration could have been different in other countries due to social, genetic and lifestyle factors.
In addition, the absence of out-of-competition urine samples impeded us to have a control to differentiate the use of caffeine on a day-to-day basis vs. Third, absorption, distribution, metabolism, and excretion of caffeine in the human body is affected by a myriad of genetic and environmental factors [ 45 ] that could affect the concentration of caffeine in urine in individuals taking the same dose before exercise.
Post-competition urinary caffeine levels might be affected by the timing of the urine sample in relation to the caffeine dose [ 46 ] or the opportunities to urinate during or after an event. In this regard, the sport disciplines analyzed in this investigation have different regulations, particularly different durations or the presence of several competitions within the same day. Since caffeine is typically consumed before exercise, a longer competition period might allow more time for metabolism and excretion of the substance, affecting those sports with longer competition durations.
In addition, caffeine could be ingested more than once in long-lasting events to maintain the effects of the substance on performance. Nevertheless, we believe that the high number of samples analyzed per year minimizes the effect of these factors on the outcomes of the investigation, and the authors believe that the data provided by this research reflect the evolution of the use of caffeine in sports.
In summary, the concentration of caffeine in the urine samples obtained after competition in Olympic sports increased from to , which might indicate a slightly higher use of this substance in both men and women athletes.
The analysis by disciplines revealed that some, but not all, sports have shown increases in the concentration of urinary caffeine, suggesting that the popularity of this substance has grown in some sports. Finally, investigations about the effects of caffeine on female athlete populations should be promoted because women athletes present slightly higher urinary concentrations than men counterparts.
The authors of this investigation want to acknowledge the effort of all the laboratory personnel of the Doping Control Laboratory in Madrid that participated in the measurement of the urine samples that made this investigation possible. Conceptualization, M. National Center for Biotechnology Information , U. Journal List Nutrients v. Published online Jan Find articles by Juan Del Coso. Author information Article notes Copyright and License information Disclaimer.
Received Nov 28; Accepted Jan This article has been cited by other articles in PMC. Abstract The ergogenic effect of caffeine is well-established, but the extent of its consumption in sport is unknown at the present.
Keywords: pharmacokinetics, energy drink, exercise, elite athlete, performance. Introduction Caffeine 1,3,7-trimethylxanthine is a stimulant naturally present in a variety of foods and drinks, although it is also artificially included in dietary and sports supplements, over-the-counter medications, and beverages.
Validation Procedure The between-days reproducibility was evaluated using 20 measurements of the calibration solution obtained over two months. Statistical Analysis All samples with a urinary caffeine concentration below the LOD were considered to be specimens without any caffeine content.
Results The median urine caffeine concentration in 0. Open in a separate window. Figure 1. Figure 2. Figure 3. Figure 4. Sport p Value Aquatics 0. Discussion The purpose of this investigation was to describe the changes in urine caffeine concentration of samples obtained in competition of Olympic sports for the years , , and Conclusions In summary, the concentration of caffeine in the urine samples obtained after competition in Olympic sports increased from to , which might indicate a slightly higher use of this substance in both men and women athletes.
Acknowledgments The authors of this investigation want to acknowledge the effort of all the laboratory personnel of the Doping Control Laboratory in Madrid that participated in the measurement of the urine samples that made this investigation possible. Author Contributions Conceptualization, M. Funding This investigation did not receive any funding. Conflicts of Interest The authors declare no conflict of interest. References 1. Souza D. Acute effects of caffeine-containing energy drinks on physical performance: A systematic review and meta-analysis.
Southward K. The effect of acute caffeine ingestion on endurance performance: A systematic review and meta-analysis. Sports Med. Grgic J. Caffeine ingestion enhances wingate performance: A meta-analysis. Sport Sci. Del Coso J. Dose response effects of a caffeine-containing energy drink on muscle performance: A repeated measures design. Sports Nutr. Effects of caffeine intake on muscle strength and power: A systematic review and meta-analysis.
Puente C. Caffeine improves basketball performance in experienced basketball players. Caffeine effects on short-term performance during prolonged exercise in the heat. Sports Exerc. Diaz-Lara F. Caffeine improves muscular performance in elite brazilian jiu-jitsu athletes. Maughan R. IOC consensus statement: Dietary supplements and the high-performance athlete. Sport Nutr. Pickering C. Are the current guidelines on caffeine use in sport optimal for everyone? Inter-individual variation in caffeine ergogenicity, and a move towards personalised sports nutrition.
Womack C. The influence of a CYP1A2 polymorphism on the ergogenic effects of caffeine. Rahimi R. The effect of CYP1A2 genotype on the ergogenic properties of caffeine during resistance exercise: A randomized, double-blind, placebo-controlled, crossover study.
Guest N. Caffeine, CYP1A2 genotype, and endurance performance in athletes. Pataky M. Caffeine and 3-km cycling performance: Effects of mouth rinsing, genotype, and time of day. Algrain H. The effects of a polymorphism in the cytochrome p CYP1A2 gene on performance enhancement with caffeine in recreational cyclists. Quick Answers. Micromedex 2. Read more Spirit of Sport blog posts. What is Caffeine? Is Caffeine Prohibited in Sport? Are there medical uses for caffeine?
Are there risks associated with caffeine? Are energy drinks and pre-workout supplements with caffeine safe for athletes to use? No, since caffeine is not prohibited, a TUE is not required to use caffeine.
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