The various supplements hydro saline can be divided into three categories: isotonic, hypotonic and hypertonic.

The isotonic supplements have osmotic pressure similar to the pressure of the blood plasma, and then allow an absorption of medium speed.

Hypotonic supplements have a lower osmotic pressure than the blood plasma and allow greater and faster absorption than the isotonic solution.

The hypertonic supplements have a osmotic pressure greater than the blood plasma and then allow a slow absorption.

The sweat has a concentration of solutes of less than all the other body fluids, with a concentration of 80-180 mOsm/l compared to 290-300 mOsm/l plasma, and this entails that sweating always determines a greater loss of water than the loss of salts. This aspect is not to be underestimated in the analysis of the correct reintegration hydro saline; fact implies that there is no need to drink beverages hydro salts in the absence of a high and prolonged perspiration. In fact, in the presence of a high not sweating the loss of mineral salts is limited and easily tolerable by the body, a simple reinstatement with natural water, in such situations, provides the best possible reinstatement. In the presence of high sweats is well, however, to proceed to an integration of mineral salts, preferably with a concentration similar to that present in sweat, then a hypotonic drink which does not alter the balance hydro physiological saline.