Background and aims: Dehydration is the most common fluid or electrolyte disorder among older persons. This study was designed to examine the hydration status of community-dwelling seniors.
Methods: Blood and urine samples were collected from 67 independently living volunteers (65-93 yrs) who had functional limitations but no condition that contraindicated 10 min of moderate exercise. Forty-six subjects who were not diabetic, had fasted for 12 hours, and had blood glucose levels < or = 115 mg/dL were thus included. Urine and serum samples were analyzed for osmolality (mosm/kg), Na+ (mmol/L) and K+ (mmol/L). Whole blood was analyzed for hemoglobin (Hb, g/dL) and hematocrit (Hct, %) and urine for specific gravity (USG). Means and standard deviations for the current data were compared with normal values.
Results: All values were within normal ranges except urine osmolality.
Conclusions: While changes associated with aging may predispose an individual to dehydration, functionally limited, independently living older individuals demonstrate normal hydration status following a 12-hr fast. This suggests that dehydration is not solely a function of the aging process, but may be more related to concomitant medical conditions or dependent living.