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How Do We Pee?

Hi friends! Are you one of the unlucky ones who has a “weak bladder?” Do you avoid drinking water because you fear it will need to make you go to the bathroom more urgently or more often? Are you running to the bathroom in the morning after drinking coffee? This week we are going to talk about how the process of peeing works in our bodies.

When we are infants, peeing happens through a reflex that we are unable to control. At anywhere from three to five years old we start to be able to gain control of this process. It is a complex process involving the brain, spinal cord, and nerves which are controlled by electrical impulses and chemicals called neurotransmitters.

The bladder is essentially a hollow ball of muscle with two modes: storage (holding pee in) and elimination (peeing).

At rest, this muscle should be relaxed, and the pelvic floor muscles are closed which allows the bladder to slowly fill with urine. In this storage phase, certain chemicals are released to prevent the bladder muscle from contracting while also keeping the opening of the bladder closed. When we are ready to pee, the bladder muscle (called the detrusor) squeezes and the pelvic floor muscles relax to open the urethra to that pee can exit the body.

As the bladder fills, it begins to expand. Receptors in the bladder send a message to the brain via the spinal cord to let it know it is starting to fill up. This first signal to void typically happens when the bladder is about 40% full. Once the brain receives the signal it will run through many different questions to decide whether to pee or whether to continue storing. Am I in the bathroom at the toilet? Is there a bathroom nearby? Is the bathroom clean? Am I in the middle of doing something? What will happen if I stop what I am doing to go to the bathroom?

Anxiety, including worrying about not being able to find a bathroom in time or others knowing we’ve had leakage, can make this urge to pee even stronger. It’s important to try to stay calm with strong urges, but that can take practice. Using distraction techniques and putting your mind on something else can help ease the sense of urgency.

Once we have made the decision to pee and find ourselves at the toilet or urinal the brain flips the switch to change from storage mode to elimination mode. This tells the bladder muscle to begin to squeeze to empty pee while telling the urethral sphincters and pelvic floor muscles to relax to allow pee to exit the body. Because the bladder muscle squeezes to empty, we should not need to strain or push to pee.

Once we are done peeing, the switch is flipped back to the storage mode telling the sphincters and pelvic floor muscles to engage and telling the bladder muscle to relax. The process is then starts over until the bladder fills and we feel the need to pee again.

This is the process for a normally functioning bladder and nervous system. If this process is disrupted, we can find ourselves in the bathroom frequently and with urge urinary incontinence. The normal time frame between trips to the bathroom should be about every two to four hours. This give the bladder adequate time to fill up and need to empty. However, there are several diseases and disorders that can alter the functioning of this system. Some common ones are an enlarged prostate, interstitial cystitis, stroke, and spinal cord injury.

Caffeine and alcohol are two of many common bladder irritants. When we consume these, our bodies feel an urge to empty quickly rather than waiting for the bladder to stretch as it fills up. Below you will find a list of some of the common bladder irritants. Keep in mind that this is not a list of things to never consume again, but rather a list to help you make smart decisions to avoid incontinent episodes. For example, if you will be without access to a bathroom for several hours, consuming these bladder irritants may not be a smart decision.

Techniques like bladder retraining can help when we are peeing too often. Your provider may have you fill out a bladder diary to keep track of your daily habits including how much and what you are drinking , how often you go, how strong the urge to go is, etc.

A pelvic floor therapist can help you develop good bladder habits and ensure you pelvic floor is working at its best. Ask you provider for a referral or find one near you at

Ready to learn more about your pelvic floor muscles? Here are some helpful resources:

For providers, check our online courses to help your clients. Consider joining our Ambassador Program and most of our courses are included with your membership!

Written by Emily Reul, PT, DPT


  1. Fowler CJ, Griffiths D, de Groat WC. The neural control of micturition. Nat Rev Neurosci.2008,l9(6):453-466.

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