Merck Manual

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Spotlight on Aging: Water Balance

Spotlight on Aging: Water Balance


Older people are particularly susceptible to dehydration. In older people, common causes of dehydration include

Additionally, older people sense thirst more slowly and less intensely than younger people do, so even those who are otherwise well may not drink enough fluids for a variety of reasons, including incontinence Urinary Incontinence in Adults Urinary incontinence is involuntary loss of urine. Incontinence can occur in both men and women at any age, but it is more common among women and older people, affecting about 30% of older women... read more Urinary Incontinence in Adults or the fear of incontinence.

Older people have a higher percentage of body fat. Because fat tissue contains less water than lean tissue, the total amount of water in the body tends to decrease with age.


In overhydration Overhydration Overhydration is an excess of water in the body. People can develop overhydration if they have a disorder that decreases the body’s ability to excrete water or increases the body's tendency... read more , the body contains too much water. In older people, the kidneys excrete excess water less efficiently, and thus older people can develop overhydration more easily than younger people do. Swelling (edema) may or may not occur.