Sports drinks do not appear to enhance performance in swimmers, a small study suggests.
New research, which is being presented at the Royal College of Paediatrics and Child Health's annual conference in Birmingham, found that among 19 competitive swimmers, drinking sports drinks had "no benefit on swimming performance".
The research team from across East Anglia set out to test whether drinking during swimming improves performance and whether isotonic sports drinks are better than water.
Over a series of 12 75-minute training sessions, the swimmers aged between 11 and 17 drank either sports drinks, water or no drinks at all.
After drinking, or not drinking, swimmers performed 10 100m maximum effort freestyle sprints at three-minute intervals.
Their performance was assessed using electronic timing equipment.
Researchers analysed data from 1,118 swims.
They found that sprint times after not drinking were 0.027 seconds faster than after drinking.
Times after drinking water were 0.151 seconds faster than after sports drink, the authors will tell the conference.
But overall, there was no performance difference between drinking regimes.
No individual athlete had progressive performance improvement with drinking water and sports drink, their study abstract concludes.
"Drinking sports drink or water over 105 minutes of sustained effort swimming (typically 3,300 to 4,200m) has no benefit on swimming performance in a non-elite athlete population," they conclude.
"Sports drinks can be considered as sugar sweetened beverages."
Commenting on the study, Gavin Partington, director general of the British Soft Drinks Association, said: "Sports drinks are specifically designed to help rehydrate during or after intense endurance exercise.
"However, there are many factors to consider, including how physically active a person is in general and what else they have consumed that day."