With aging, what changes occur in water intake?

• A. Increased thirst and increased kidney function
• B. Loss of thirst mechanism and decline in kidney function
• C. No change in thirst or kidney function
• D. Increased saliva production

Answer: (B)

With aging, hydration regulation shifts due to two main changes: thirst perception and kidney function. The thirst mechanism tends to become blunted, so older adults may not feel thirsty even when starting to become dehydrated. At the same time, kidney function typically declines with age, reducing the kidneys’ ability to concentrate urine and conserve water. Together, these changes lower both the drive to drink and the body’s capacity to maintain fluid balance, raising the risk of dehydration, especially during illness, heat, or limited fluid access. The other options don’t fit because they suggest more thirst, better kidney function, or changes in saliva unrelated to the typical aging pattern.