Holding urine has all the harms but none of the benefits. First of all, I would like to introduce you to a concept: safe bladder capacity Urine production is a continuous process, and urine is produced from the kidneys and then transported into the bladder by the ureter. In a normal state, the ureter has the function of stopping the reflux of urine into the kidneys. When the bladder receives urine to expand, it closes because of the pressure at the entrance, and this stops the reflux of urine inside the bladder into the kidneys. However, once the bladder holds more than a certain volume of urine, the anti-reflux mechanism disappears, and urine may reflux from the bladder into the kidneys when the pressure inside the bladder continues to rise. When does urine reflux? Do you remember that we used to use liquefied gas and usually a safety valve was added to remind the pressure inside the gas tank not to be too high? So is there a safe pressure for the bladder? Yes, there is, and it should not exceed a pressure of 40 cm of water column. We urologists usually consider the bladder capacity when the forced urinary muscle pressure reaches 40 cm H2O as the relatively safe capacity. With high pressure, the gas tank will explode, while in general, the bladder will not explode, but the urine will have to find an outlet, either running upwards (reflux into the kidneys) or downwards (incontinence). Usually, we go to pee before the pressure in the bladder is that high – it’s a self-preservation instinct. However, in some special circumstances, such as free highways, long lines at the girls’ restrooms, buying train station tickets for the Spring Festival, or staying under the covers at night in winter, etc., people will intentionally or unintentionally postpone urination or even hold back urination, and when the urine in the bladder exceeds the “safe capacity”, it will produce various The hazards. 1, urinary tract infection: it is often said that running water does not rot, once the urine in the bladder for a long time, it will easily lead to acute bladder inflammation, which is very common in women of childbearing age. Many of the female patients with cystitis seen in outpatient clinics have a predisposing factor of holding urine. In addition, the kidneys and ureters are usually sterile, and when the bladder has a reflux of urine due to holding urine, it can bring bacteria from the bladder or from outside into the kidneys, causing a retrograde infection. The presence of pyelonephritis causes much more harm than cystitis and is relatively complicated to treat. 2, bladder rupture: the bladder is a “flexing and stretching” organ, no urine when the bladder wall is very thick, and when filled with urine after the muscle layer is rapidly thinning, after holding urine bladder overfilled its thickness is even only a few millimeters, is very weak. At this time, if you encounter external force or violent blows (such as not quite fall, or small abdominal impact), the bladder is more likely to rupture. I once treated a case of betting on drinking beer to hold back urine and finally break the bladder. 3, difficult to urinate: long-term holding urine, so that the bladder’s forced urinary muscle continues to expand, resulting in a state of excessive fatigue, when you want to urinate instead of play a role. If there are underlying diseases such as prostate enlargement, this condition is very likely to cause acute urinary retention, and once it happens, emergency catheterization is needed. For young people or children, holding urine for a long time may also cause a contradiction in the work between the bladder and urethra (dysfunction of the synergistic muscles of the detrusor), causing difficulty in urination and impairing bladder function. 4, induce tumors: Although there is no direct evidence to confirm that holding urine will lead to bladder tumors, the longer urine stays in the bladder, the stronger the damage to the bladder mucosa from harmful substances, and the higher the risk of bladder tumors is presumed to occur. It can be seen that holding urine for a long time can damage your body in many ways, so for your health, please try not to hold urine.