Reply: Letter to Editor

The reason why caffeine was removed from the WADA doping list is that its presence is ubiquitous and because ergogenic effects can be obtained using doses resulting in concentrations far below the former threshold level of 12 µg/ml. As stated, doses between 3 and 6 mg/kg can result in ergogenic effects, especially in endurance performance [[1], [2]]. These doses generally do not result in urinary concentrations above the former threshold level of 12 µg/ml. However, following the results from this publication [[3]] and the results obtained before the removal of caffeine from the doping list [[4]], monitored caffeine concentrations in endurance sports and especially sports emphasising on muscle growth are significantly higher compared to other sports such as ball sports although the effect of caffeine on strength is not yet proven. Education of athletes, trainers, physicians, coaches, … should always be the first tool in the fight against doping. Despite these efforts, some athletes will continue in their use of ergogenic aids to enhance performance and a principle frequently used is that “the more they take, the better their performance will be”. This is for instance proven by the significantly higher concentrations observed in cycling and power lifting over a period of 11 years [[3], [4]]. This research has also shown that six samples analysed after the removal of caffeine from the doping list contained caffeine in concentrations exceeding 12 µg/ml of which 5 even exceeded 16 µg/ml. As the goal of doping control is to prevent the misuse of ergogenic aids, athletes abusing these drugs to enhance performance should be banned from sports. The results following this publication show that the threshold level of 12 µg/ml is capable of distinguishing use from abuse. Although not all cheaters will be tracked using this threshold, doping control authorities should try to minimize the number of athletes using performance enhancing drugs such as caffeine. Placing caffeine back on the doping list supports this principle.

References

• 1 Graham T E. Caffeine and exercise - Metabolism, endurance and performance.  Sports Med. 2001;  31 785-807
• 2 Kovacs E MR, Stegen J HCH, Brouns F. Effect of caffeinated drinks on substrate metabolism, caffeine excretion and performance.  J Appl Physiol. 1998;  85 709-715
• 3 Van Thuyne W, Delbeke F T. Distribution of caffeine levels in urine in different sports related to doping control before and after the removal of caffeine from the WADA doping list.  Int J Sports Med. 2006;  27 745-750
• 4 Van Thuyne W, Roels K, Delbeke F T. Distribution of caffeine levels in urine in different sports in relation to doping control.  Int J Sports Med. 2005;  26 714-718