As individuals age, the proportion of water in the body generally...

As individuals age, the proportion of water in the body generally falls due to several physiological changes that occur. One of the primary reasons for this decrease is related to the loss of lean body mass, including muscle, which is rich in water. As people age, they tend to lose muscle and gain fat, and adipose (fat) tissue contains less water than lean tissue.

Additionally, changes in kidney function and hormonal regulation can lead to alterations in fluid balance, contributing to a decreased total body water content. Hydration strategies may also be less effective in older adults, as their thirst sensation can diminish, leading to less fluid intake. Taken together, these factors result in a reduced percentage of body water as individuals grow older. Understanding this shift is important in clinical settings, as older adults may be more susceptible to dehydration and other complications related to fluid balance.