Volunteers were supervised drinking 1.5 l of the drinks within 1 h for 10 working days according to a pre-determined randomisation schedule. Prior to consumption of the study drinks (between 12 noon and 2 p.m.) the splint must have been in situ for at least 5 min. Each volunteer was issued with a measuring beaker and a stopwatch and was asked to drink 35 ml/min for 10 min, followed by a 5-min rest period, then 130 ml per 5 min for 25 min, followed by a 5-min rest period and finally 50 ml/min for 10 min followed by a 5-min rest period