Do you routinely go to the bathroom before you leave the house, go into a meeting, go to bed, workout etc…? You may be training your bladder to signal your brain that it is time to empty before the bladder is actually full.
A healthy adult bladder can hold up to 2 cups or 16 ounces of urine during the day and can stretch more at night while you are sleeping. When the bladder is about halfway full, stretch receptors from the bladder muscle stimulate a reflex telling your brain you need to pee. We have something in our urethra called an external sphincter that we can voluntarily control. Relaxing or contracting this sphincter determines whether urine is allowed to exit the body. Contracting the external sphincter will calm the bladder and the urge to urinate will dissipate. Below is a picture of the micturition (voiding or peeing) reflex that shows how the brain and bladder communicate.
Reference: https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-control-nerve-disease
When you urinate “just in case,” you may be emptying your bladder when it is less than half full. Repeatedly doing this will train your bladder to think it is full when it is not. The stretch receptors in the bladder will begin to send signals to your brain at lower and lower thresholds, creating the urge to urinate more and more frequently.
In my practice as a pelvic floor therapist, I see the habit of “just in case” voids all too often. Usually, it starts as a behavior learned early in life or during pregnancy. Take note of your current habits. Do you void frequently during the day (> 7-8 times)? Do you void frequently during the night (>1-2 times)? Do you pee out of habit or truly when you feel a strong urge because your bladder is actually full? Just as the bladder can be trained to hold less urine, with physical therapy, the bladder can also be trained to comfortably hold more!