Abstract

Background. Normohydration represents a key condition for physical practice and muscular performance: hypohydration can infact impair exercise capability and finally cause serious disability or even death, particularly in hot and humid enviroments. Rehydration can be achieved only if sweat electrolyte losses as well as water are replaced. The speed of rehydration becomes fundamental in intermittent or long lasting exercise and it depends on sodium and potassium concentrations of drinks consumed. Bioelectrical Impedance Analysis (BIA) allows to estimate body fluid compartments at rest and after acute variations of body hydration level. Aim of the study was to compare two different type of waters (higher electrolyte concentrations water: Na+ 114 mg /L, K+ 12 mg /L, Ca++ 202 mg /L in spite of oligomineral water: Na+ 7 mg/L, K+ 1 mg /L, Ca++ 46 mg /L) in order to assess a quickly restoration of fluid balance. Methods. Body fluid compartments of twenty-seven athletes (10 female) who were practicing soccer (18) and tennis (9), aged 26.8±4.5 years, were evaluated with BIA on three different occasions: 1) euhydration at rest, 2) after exercise-induced dehydration (120 min at 60-80% of maximal heart rate, at 38°C and 60% of relative humidity), 3) rehydration after drinking 25 cc of high-electrolyte water (Uliveto) every 5 min untill it was reached body weight or oligomineral water. In similar environments conditions, all these measurements were repeated one day after reversing type of water. Results. Exercise-induced body weight loss was of 2.1 and 2 %, respectively (p=N.S.). Rehydration with high-electrolyte water was faster than oligomineral water for body cellular mass (44.0 vs 41.9%, p<0.0001), in spite of lower values of extra cellular water (26.0 vs 27.0 %, p<0.05). Conclusions. In conclusions high-electrolyte water seems to improve intracellular restoration process, according to the potassium role. Verf.-Referat