Blood volume changes and water appearance in the circulation from water and 3% and 6% carbohydrate drinks

This study investigated water absorption and blood volume changes after drinking water and 3% and 6% carbohydrate drinks. Nine healthy male volunteers completed this crossover study after giving informed consent to participate. On three separate occasions they consumed 500 ml of Evian water (W), a 3% carbohydrate drink (3% CHO) or a 6% carbohydrate drink (6% CHO) to which had been added 10.00±0.01 g of deuterium oxide. Blood samples were collected 10 and 5 min before drink ingestion and at 2, 5, 10, 15, 20, 30, 45 and 60 min after drink ingestion. In addition, subjective feeling questionnaires were completed at intervals throughout and subjects urinated before and after the study period. Blood samples were analysed for haematocrit and haemoglobin, glucose and deuterium concentrations. There was a significant increase in blood glucose concentration after consumption of both the 3% CHO and 6% CHO drinks, with the increase being greater after consumption of the 6% CHO drink. Both the 3% CHO and 6% CHO drinks promoted a significant blood and plasma volume expansion after their consumption whereas there was no change in blood and plasma volumes when water was consumed. Blood deuterium enrichment increased after consumption of all three drinks, but there was no significant difference between drinks. The results suggest that when a significant expansion of blood volume is desired, this can be achieved by consumption of the 3% CHO or 6% CHO drink rather than with plain water consumption. This is likely to be due to the sodium and carbohydrate content of these drinks.