How well do different drinks hydrate? Development of a hydration index.
This study was sponsored by the European Hydration Institute and undertaken by teams at the University of Stirling, Loughborough University and Bangor University.
Phase one aimed to investigate the effects of 13 commonly-consumed drinks on urine output, and therefore fluid balance, when ingested in a euhydrated state, with a view to establishing a Hydration Index.
Phase two involved three separate studies to investigate the relative influence of individual drink components (carbohydrate, sodium, and caffeine) on the Hydration Index and net fluid balance.
In the study, 72 men who were euhydrated and had fasted ingested one litre of still water or one of three other commercially-available beverages over a period of 30 minutes. Urine output was then collected for the subsequent four hours. The Hydration Index was corrected for the water content of the other drinks, and was calculated as the amount of water retained at two hours after ingestion, relative to the amount of water retained after the ingestion of plain still water.
Watch a video about the study:
Watch a webinar featuring Professor Ron Maughan and Dr Stuart Galloway:
Watch a presentation about the study by Dr Stuart Galloway from the University of Stirling: