Which population tends to have a reduced fluid reserve in their body?

The population that tends to have a reduced fluid reserve in their body is often associated with infants, as they have a higher risk of dehydration compared to other age groups. Infants have a larger body surface area relative to their volume, leading to increased fluid loss through the skin and more sensitive metabolic rates. This makes them more susceptible to fluctuations in fluid balance.

While it may seem intuitive to consider factors like obesity, the key aspect is that infants, due to their immature renal function and developmental stage, may not be able to conserve fluids as effectively as older children or adults. The combination of their high turnover of bodily fluids and the demands of growth can lead to a rapid depletion of their fluid reserves if not properly managed.

In contrast, teenagers and adults typically have more advanced physiological mechanisms for managing hydration and nutrient needs, while seniors may have altered thirst mechanisms and renal function, but they do not inherently possess the same level of vulnerability when it comes to fluid reserves as infants do. Athletes and children also typically have better fluid regulation mechanisms than infants. Therefore, while other populations may experience fluid imbalance, infants uniquely reflect a critical reduction in fluid reserve capacity in this context.