Why does immobility increase the risk of urinary problems?

• A. The bladder empties more completely, reducing UTIs.
• B. Bladder emptying is unaffected by gravity.
• C. Bladder does not fully empty against gravity, increasing risk of UTIs and stones.
• D. Urine production decreases.

Answer: (C)

When someone is immobile, the ability of the bladder to empty completely can be reduced. The bladder relies on coordinated detrusor muscle contraction and relaxation of the sphincters to push urine out through the urethra. If mobility is limited, pelvic and abdominal muscle support, as well as detrusor function, may be less effective, so not all urine is expelled.

Residual urine left in the bladder creates a favorable environment for bacteria to grow, which raises the risk of urinary tract infections. It also concentrates minerals in the urine, promoting stone formation over time. Because urine production itself isn’t typically decreased by immobility, the problem is the incomplete emptying and the resulting urinary stasis, not a drop in how much urine the kidneys produce.