Caffeine: use and abuse in sports.

The urinary caffeine content was compared between a control group and 775 cyclists checked for doping during the 1982 season. The data for sportsmen demonstrate that the (mis)use of caffeine is more pronounced in both professional and amateur classes than in the younger categories (debutant and junior). Caffeine was also monitored during a 60-h period in the urine of several coffee drinkers. Based on all results, a "maximum level of caffeine" of 15 micrograms X ml-1 in urine for sporting competitions is proposed.