What is considered frequent urination?

Frequent urination, also known as urinary frequency, excessive urination or an overactive bladder, describes the need to urinate more than eight times a day or waking up more than once during the night to go to the toilet (also known as nocturia).

A healthy bladder can hold between 1.5 to 2 cups of urine (300 to 500 ml), how often a person needs to urinate will depend on how quickly their kidneys produce urine which fills the bladder¹. When the bladder fills to capacity, signals will be sent to the brain to inform the person that they may need to urinate soon.

** My Med Memo - The average person urinates between four and seven times when drinking roughly two litres of fluid a day.

The most obvious cause of frequent urination is drinking excessive amounts of fluid. In this instance, reducing fluid intake will remedy the issue. Medically, frequent urination may be a primary health issue or a symptom of an underlying health-related concern.

Frequent urination can affect anyone at any age but becomes increasingly common in middle age and during pregnancy. There are also a number of medical reasons why one may suffer from the condition, the most common of which is due to an infection of the urinary tract or bladder which causes the bladder to contract and reduces the bladder’s ability to hold urine. Click on the navigation panel above to explore the other causes of frequent urination.  

While it may cause inconvenience to the sufferer and keep those suffering from nocturia out of sleep, it is generally a manageable condition and any underlying causes can usually be treated successfully. 

How does my bladder work?

Before we get into the details of frequent urination, it is important to understand the physiology involved and how the bladder works.

The bladder is situated in the lower abdomen. This hollow organ is responsible for storing and expelling urine. When emptied, the bladder is the size and shape of a pear, as urine starts to accumulate within it, the muscles of the bladder walls relax in order for it to expand. As the bladder empties when urinating, the muscles contract in order for the urine to be squeezed out through the urethra (the tube that connects the bladder to the outside of the body and transports urine).

If something irritates the bladder, such as an infection, the resulting inflammation will lead to a stiffening of the bladder lining/wall and make it difficult for the bladder to expand fully when urine begins to fill it. This can lead to a frequent urge to urinate even when the bladder does not contain a large quantity of urine. 

How does urination work?

Urination is a more complex process than one may think. When your bladder begins to fill with urine, nerves in the bladder wall communicate with the brain and spinal cord (also known as the CNS (central nervous system), informing them that you need to go to the toilet.

As a response to this, the spinal cord will send a message to your bladder, informing it to contract, this is known as the voiding reflex. If you ignore the urge to urinate, then your brain will override the voiding reflex. When you do go to the toilet and allow this reflex to take place, urination will occur, and voiding will be sustained until the bladder has sufficiently emptied itself of urine.

Any issues affecting the muscles of your bladder wall or this pathway of nerves and communication, may result in bladder dysfunction such as frequent urination.

^References:

^{1.NIDDK.  The Urinary Tract & How It Works. Available: https://www.niddk.nih.gov/health-information/urologic-diseases/urinary-tract-how-it-works [Accessed 24.10.2017]}