The kidneys filter the blood and help remove waste and extra fluid from the body. The kidneys also help control the body's chemical balance.

The kidneys are part of the urinary system, which also includes the ureters, bladder, and urethra.

Bladder control can be affected by muscle changes and changes in the reproductive system.

Aging Changes and Their Effects on the Kidneys and Bladder 

As you age, your kidneys and bladder change. This can affect their functions.

Changes in the kidneys:

As the kidneys age, these events occur:

• Overall amount of kidney tissue decreases.
• Number of filtering units (nephrons) decreases. Nephrons filter waste material from the blood.
• Blood vessels supplying the kidneys can become hardened. This causes the kidneys to filter blood more slowly.

Changes in the bladder:

• The bladder wall changes. The elastic tissue becomes tough and the bladder becomes less stretchy. The bladder cannot hold as much urine as before.
• The bladder muscles weaken.
• Blockage of the urethra: In women this can be due to weakened muscles that cause the bladder or vagina to fall out of position (prolapse). In men the urethra can become blocked by an enlarged prostate gland.

In a healthy aging person, kidney function remains normal. Illness, medications, and other conditions, though, can affect the ability of the kidneys to function properly.

Common Problems

Aging increases the risk of kidney and bladder problems such as:

• Bladder control issues (urinary incontinence or leakage, or urinary retention, which means you are not able to completely empty your bladder)
• Bladder and other urinary tract infections (UTIs)
• Chronic kidney disease

When to Contact a Medical Professional

Call your health care provider right away if you have any of the following:

• Signs of a urinary tract infection, including fever or chills, nausea and vomiting, extreme tiredness, low back pain
• Very dark urine or fresh blood in the urine
• Trouble urinating
• Urinating more often than usual
• Sudden need to urinate (urinary urgency)

As You Grow Older, You Will Have Other Changes, Including:

• In the bones, muscles, and joints
• In the male reproductive system
• In the female reproductive system
• In organs, tissues, and cells

Cohan ME, Pikna JK, Duecy E. Urinary incontinence. In: Duthie EH, Katz PR, Malone ML, eds. Practice of Geriatrics. 4th ed. Philadelphia, PA: Elsevier Mosby; 2007:chap 16.

Minaker KL. Common clinical sequaelae of aging. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 24.

Patel SR, Wiggins J. Renal and electrolyte disorders. In: Duthie EH, Katz PR, Malone ML, eds. Practice of Geriatrics. 4th ed. Philadelphia, PA: Elsevier Mosby; 2007:chap 44.