Renal function
volume overload
VOLUME OVERLOAD, FLUID RETENTION
The ability to concentrate urine declines with age. In the Baltimore Longitudinal Study of Ageing, individuals aged 60–79 years had a ~ 20% reduction in maximal urine osmolality, a 50% decrease in the ability to reabsorb sodium and urea, and reduced capacity to concentrate solutes, when compared with 20–39 years old group (Lindeman et al. In the present study, the volume overload induced by ingesting 1 L of fluid in 1 h, when in an already euhydrated state, leads to a more prolonged fluid retention of water in older adults, likely due to a reduced homeostatic control response compared to young adults (Beck 