Urinating is a routine biological process. Delaying urination is common, as the urinary system is built with a certain tolerance for temporary storage, allowing individuals to maintain continence until an appropriate time and place. However, the body is not engineered for indefinite retention, and frequently ignoring the urge to void can put undue stress on the system, leading to various health issues.
How the Bladder Manages Storage
The urinary bladder is a hollow, muscular organ whose primary function is the temporary storage of urine. This storage capacity is made possible by the detrusor muscle, a smooth muscle that forms the wall of the bladder and relaxes to allow the organ to fill and stretch. An adult bladder can typically hold up to 400 to 500 milliliters of urine before the urge to urinate becomes strong.
As the bladder fills, stretch receptors in the wall send signals via the nervous system to the brain, communicating the sensation of fullness. To keep urine contained, two sphincter muscles control the exit of the bladder into the urethra. The internal urethral sphincter, made of smooth muscle, is under involuntary control, while the external urethral sphincter is composed of skeletal muscle, which allows for conscious, voluntary control over when to urinate.
During the storage phase, the sympathetic nervous system promotes relaxation of the detrusor muscle while stimulating the internal sphincter to contract. When a person is ready to void, the parasympathetic nervous system takes over, signaling the detrusor muscle to contract and the sphincters to relax. Deliberately holding urine involves consciously maintaining contraction of the external urethral sphincter against the increasing pressure from the full bladder.
Short-Term Health Risks
The most immediate concern from delaying urination is the development of a Urinary Tract Infection (UTI). Regular expulsion of urine helps flush out any bacteria that may have entered the urinary tract. When urine is held for an extended period, the resulting urinary stasis provides an environment where bacteria can multiply rapidly.
This proliferation of bacteria within the bladder increases the likelihood of an infection, which can cause symptoms like a burning sensation during urination or a constant, strong urge to void. Holding urine can also cause acute discomfort and pain in the bladder or lower abdomen due to the stretching of the organ walls. Upon finally attempting to urinate, some individuals may also experience temporary difficulty initiating the flow, known as hesitancy, because the muscles have been strained from prolonged voluntary contraction.
Potential Long-Term Damage
Habitually holding urine can lead to serious, chronic issues that affect the structure and function of the urinary system. Persistent overstretching of the bladder can cause the detrusor muscle to become weakened. This weakening, often referred to as bladder overdistention, can impair the muscle’s ability to contract effectively, leading to chronic urinary retention.
Chronic urinary retention means the bladder is unable to empty completely, leaving residual urine after voiding. This incomplete emptying further perpetuates the risk of recurrent UTIs and, in severe cases, can lead to the formation of bladder stones. The most severe complication arises when the high pressure from the retained urine causes it to back up through the ureters toward the kidneys, a condition known as vesicoureteral reflux.
This backward flow can transport bacteria from the bladder directly into the kidneys, resulting in a kidney infection (pyelonephritis), which can lead to permanent renal scarring and a decline in kidney function over time. Consistently ignoring the body’s signals places unnecessary strain on the entire urinary tract, making the practice medically discouraged.