Which statement best describes aging-related changes in urine concentration ability?

• A. Increased ability to concentrate urine
• B. Reduced ability to concentrate urine
• C. No change in urine concentration
• D. Fluctuating urine concentration depending on hydration

Answer: (B)

Aging affects the kidneys’ ability to concentrate urine. As people get older, there is a loss of nephrons, a decline in the medullary concentration gradient, and reduced responsiveness to antidiuretic hormone, along with decreased renal blood flow. These changes make it harder for the kidneys to reabsorb water when needed, so urine becomes less concentrated. Clinically, this means older adults often produce more dilute urine and are at greater risk for dehydration, especially with limited fluid intake or illness. Therefore, the statement that best describes aging-related changes is a reduced ability to concentrate urine. An increased ability would not occur with aging, no change ignores established changes, and while hydration can affect urine, the underlying aging trend is a reduction in concentrating capacity.