Do elderly persons need to be encouraged to drink more fluids?

Background. A recently published and widely quoted modified food guide pyra mid encourages persons over the age of 70 years to ingest eight glasses (2 liters) of fluids per day. We challenge the need for this much fluid intake and even question whether it may do more harm than good. Methods. Equal numbers of Hispanic and non-Hispanic white men and women wer e selected randomly from the Health Care Financing Administration (Medicare ) rolls and recruited fora home interview followed by a 4-hour interview/ex amination in a senior health clinic. Questionnaires and examinations were u sed to determine usual daily self-reported intake of fluids, lying and stan ding blood pressures, history of falls over the past year, and the presence of chronic constipation and chronic fatigue or tiredness. Serum samples we re obtained for determination of sodium, urea nitrogen (SUN) and creatinine concentrations, and calculation of SUN/creatinine ratios. Results. Interviews/examinations were conducted on 883 volunteers (mean age of 74.1 years). Most participants (71%) estimated that their usual fluid i ntake was equal to or exceeded six glasses per day. Evidence of hypernatrem ia (serum sodium concentration > 146 mEq/l) was not observed in the 227 ind ividuals ingesting less than this. Hyponatremia also was rare in this popul ation. Fluid intake showed no significant associations with lying and stand ing blood pressures, a history of falling, or the frequency of chronic cons tipation or fatigue/tiredness. Conclusion. Until we have more evidence-based documentation that fluid inta ke of eight glasses (2 liters) per day improves some aspect of an elderly p erson's health, encouraging a fluid intake above a level that is comfortabl e for the individual seems to serve little useful purpose.