The kidneys become smaller because the number of cells decreases. Less blood flows through the kidneys, at about age 30, they begin to filter blood less well. Especially the kidneys are a physical condition dependent organ. Persons with a good physical condition and active lifestyle favor positively of this with better functioning kidney system. As the year’s pass, they remove waste products from the bloodless well. They excrete too much water and too little salt, making dehydration more likely. Nonetheless, they almost always function well enough to meet the body’s needs.
Certain changes in the urinary tract may make controlling urination more difficult:
The maximum volume of urine that the bladder can hold decreases. Older people need to urinate more often.
The bladder muscles contract unpredictably (become overactive), regardless of whether people need to urinate (constant feeling of the need “to go” )
The bladder muscles weaken, the contraction is not maximal. As a result, they cannot empty the bladder as well, and more urine is left in the bladder after urination.
The muscle that controls the passage of urine out of the body (urinary sphincter) is less able to close tightly and prevent leakage. Older people have more difficulty postponing urination. These changes are one reason that urinary incontinence (uncontrollable loss of urine) becomes more common as people age.
In women, the urethra (the tube through which urine leaves the body) shortens, and its lining becomes thinner. The decrease in the estrogen level that occurs with menopause contributes to this and other changes in the urinary tract.
In men, the prostate gland tends to enlarge. In many men, it enlarges enough to interfere with the passage of urine and to prevent the bladder from emptying completely. As a result, older men urinate with less force, take longer to start the stream of urine, dribbling urine at the end of the stream, and to urinate more often. Older men are also more likely to be unable to urinate despite having a full bladder (called urinary retention). This disorder requires immediate medical care.