[Hydrosodium balance in aging]. / La balance hydrosodée au cours du vieillissement.

One of the kidney's major functions is to adjust the water and sodium balance in order to maintain a state of equilibrium. In the course of aging, even in the absence of renal pathology, changes are observed not only in renal macrostructure (reduction in kidney size, increase in the number of cysts), but also in microstructure (arteriosclerosis, glomerulosclerosis, fibrosis and tubular atrophy). All these changes can disrupt the homeostasis of water and sodium balances. The aim of this article is to review the physiology of water and sodium stores, and to assess the impact of aging on the regulatory loops of these different systems.