Usually holding urine can be harmless, but there are some cases in which this practice can pose a threat to your health, especially if it becomes a habit.
Dr. Jason Kim, a clinical associate professor of urology at the Renaissance School of Medicine at Long Island University in New York, said that there is a complex nervous system that controls urination. Your kidneys make urine, and then it is collected in the bladder through two tubes called ureters.
Once the bladder is about half full, nerve receptors tell the brain that it is time to urinate, and the brain signals the bladder that it is time to urinate.
Holding urine at such a point can increase your risk of developing a urinary tract infection (UTI), which can result in bacteria infecting the urethra.
Holding urine can lead to bacterial growth. This is why people, especially women, are told to urinate after sex because sex introduces bacteria into the urethra.
If left untreated, a UTI can progress to the kidneys, leading to a kidney infection, and if not treated early, it can lead to urosepsis, which is an infection of the urinary tract.
Furthermore, if you hold your urine for a long time, it can weaken the bladder muscles over time. As a result, the bladder is unable to fully empty itself. In other words, urine left in the bladder increases the risk of infection.