What are fluid requirements for healthy adults > 75 years old?

• A. 20 ml/kg
• B. 25 ml/kg
• C. 30 ml/kg
• D. 35 ml/kg

Answer: (B)

In healthy older adults, maintenance fluid needs are typically about 25 ml per kilogram of body weight per day. This value accounts for age-related decreases in total body water and renal reserve, as well as a tendency toward reduced thirst sensation. It provides enough hydration to meet daily needs without adding excess fluid that could lead to overload in someone who may have limited cardiac or kidney reserve.

For example, a person weighing 70 kg would aim for roughly 1.7 liters of fluid per day. Values higher than this (such as 30–35 ml/kg/day) can increase the risk of fluid overload in the elderly, while a much lower target (like 20 ml/kg/day) may risk dehydration given reduced thirst and intake. In practice, adjust for individual factors such as comorbidities, kidney function, medications, and any ongoing fluid losses, and monitor hydration status regularly.