Abstract

It is clear from the available information that rehydration after exercise can only be achieved if the sodium lost in sweat is replaced as well as the volume loss. It might be suggested therefore that rehydration drinks should have a sodium concentration similar to that of sweat. However, the sodium content of sweat varies widely, and no single formulation will meet this requirement for all individuals in all situations. The upper end of the normal range for sodium concentration (80 mmol/l), however, is similar to the sodium concentration of many commercially produced oral rehydration solutions (ORS) intended for use in the treatment of diarrhoea-induced dehydration, and some of these are not unpalatable. In contrast, the sodium content of most sports drinks is in the range of 10-30 mmol/l and is even lower in some cases; most commonly consumed soft drinks contain virtually no sodium and these drinks are therefore unsuitable when the need for rehydration is crucial. The problem with high sodium concentrations is that this may exert a negative effect on taste, resulting in a reduced consumption. A key recommendation should be that the volume of fluid ingested after exercise where significant sweat losses have occurred must be substantially greater than the volume of sweat lost. This clearly requires a knowledge of sweat loss, and a reasonable estimate is obtained from changes in body mass. The effective rehydration drink intended for consumption after exercise should be both effective and palatable. Verf.-Referat