 Verbal and written guidelines will be given for the patient to ingest the daily volume of water calculated by the weight 30 ml kg day for 14 days. Patients will receive an acrylic glass with a mark in 200 ml and will be instructed to take the number of glasses a day corresponding to the calculated volume 30 ml kg. Patients will also receive a leaflet indicating how many glasses of water they will need to take. They will also be instructed to mark with an X the number of glasses of water that they actually drank daily during the fourteen days of intervention. 