Frequent urination (polyuria): Causes, associated symptoms and treatment

Key takeaways

• Frequent urination, or polyuria, is the excretion of excessive amounts of urine. Individuals with this condition can pass out more than 3 liters of urine in 24 hours. 
• People who commonly experience polyuria are the elderly, pregnant women, and individuals with underlying health issues such as diabetes mellitus, diabetes insipidus, primary polydipsia, and chronic renal failure.
• When polyuria occurs at night, it is called nocturia. Bladder storage problems and sleeping disorders are possible causes of nocturia. 
• Reducing your alcohol and caffeine intake, as well as overall fluid intake, especially before bed, can help prevent frequent urination if it isn't caused by any underlying health issues. 

Frequent urination, also known as polyuria, is a health condition characterized by increased or excessive excretion of urine from the body. This condition can affect both men and women. 

When you drink water, most of it is absorbed into your blood. Once in the bloodstream, the kidneys filter out excess water, electrolytes, and toxins, forming urine. This urine gradually accumulates in the bladder until it’s eventually passed from the body.

On average, the kidneys make about 1.7 liters of urine daily. However, the bladder's capacity is limited to only fitting a 500–700 ml volume, meaning you have to use the restroom more than once a day. Furthermore, the urge to urinate begins before the bladder is full, typically when it contains about 200 or 350 ml of urine.

A daily urine output below 3 liters is considered healthy for most people. Hence, exceeding this amount every day may be regarded as polyuria.

If you’re drinking more water, you’ll consequently make more urine. Polyuria is mostly common in pregnant and older people, but it could also be a sign of more serious underlying health problems. Frequent urination can affect a person’s daily life by causing discomfort and inconvenience because of the urge to urinate regularly. 

Possible causes of frequent urination

Let's have a look at some of the possible causes of polyuria. 

1. Diabetes mellitus

Polyuria is common in patients with type 1 or type 2 diabetes mellitus, a health condition that causes an abnormal spike in blood glucose levels. 

The body rids itself of the excess glucose in the bloodstream through the kidneys to restore balance. However, the excess sugar now in the urine also drags along extra water, thus increasing the total volume of urine produced.  

The increased water loss in polyuria results in polydipsia (excessive thirst), causing people with this condition to drink water excessively. This is another common symptom of diabetes.

2. Diabetes Insipidus

Diabetes insipidus is another form of diabetes that causes polyuria, which in turn results in polydipsia. In diabetes insipidus, the blood glucose level is normal; however, the kidneys struggle to concentrate urine due to a malfunction in the brain or problems with a hormone called vasopressin. 

Vasopressin, or antidiuretic hormone, helps your kidneys conserve fluid by reabsorbing water from urine. When levels of this hormone are too low, this water reabsorption fails to occur, resulting in excessive fluid loss. 

3. Pregnancy

Pregnant people can experience frequent urination due to hormonal changes that occur during the early stages of pregnancy and physical changes like weak pelvic floor muscles, which are the muscles that support organs like the bladder, uterus, and bowel. 

Pregnant women can also suffer from gestational diabetes insipidus. Gestational diabetes insipidus is a rare, temporary condition that can induce polyuria and polydipsia (excessive drinking) during pregnancy. Thankfully, these symptoms gradually disappear a few weeks after childbirth.

4. Enlarged prostate

The prostate is a male organ located just below the bladder and slightly above the urethra (the tube connecting the bladder to the penis). When it’s enlarged, the prostate puts pressure on the bladder and urethra, increasing the urge to urinate while decreasing outflow. 

The prostate may be enlarged due to conditions like prostate cancer and benign prostatic hyperplasia.

5. Age

As we get older, the storage capacity of the bladder decreases. This explains why polyuria is more common with older age.

Certain health conditions that are common in elderly individuals, such as hypertension, diabetes mellitus, diabetes insipidus, congestive heart failure, and sleep apnea, can also contribute to the development of polyuria.

6. Medications

Some commonly prescribed drugs that can make you urinate more frequently include oral estrogens, alpha-blocking agents, benzodiazepines, antidepressants, antipsychotics, angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), narcotics, and calcium channel blockers.  

Recent research studies also linked glycopyrrolate (an anticholinergic drug used to reduce airway and gastric secretions) as well as other medications like dexmedetomidine, sevoflurane, methotrexate, lithium, cimetidine, and gemfibrozil to polyuria.

Additionally, diuretics are another group of medications that are well-known for causing polyuria. These medications are commonly prescribed to patients with heart failure and high blood pressure. Some common diuretics are furosemide (Lasix), hydrochlorothiazide, and indapamide (Lozide).

7. Primary polydipsia

Primary polydipsia entails the excess consumption of water or other fluids, thereby resulting in the frequent urination of dilute urine. This may ultimately cause hyponatremia (an excessive loss of sodium in the blood).

There are two types of primary polydipsia. 

• Psychogenic polydipsia: This is usually seen in psychiatric patients who have the unusual compulsion to consume large volumes of water.
• Dipsogenic polydipsia: This is seen in individuals who knowingly and excessively consume water and/or other health fluids due to certain perceived health benefits or due to damage to their hypothalamus. 

8. Chronic kidney/renal failure

The kidneys' main function is to maintain the balance between water intake and water loss. In renal failure, the kidney’s ability to filter and absorb fluid and electrolytes is disrupted, throwing off water balance.

The two most common causes of chronic kidney/renal failure are diabetes and high blood pressure.

9. Lower urinary tract infections

Lower urinary tract infections (UTIs), also known as uncomplicated urinary tract infections or cystitis, affect the urethra and the bladder. These conditions may be caused by bacteria that live in the digestive system, skin, or anus. The causative organisms enter the urethra through various means, including sexual intercourse, and then proceed to cause harm.

Lower UTIs are primarily seen in females and are also one of the most common causes of polyuria, dysuria (painful urination), and hematuria (blood in urine). 

10. Sickle cell disease

Sickle cell disease is one of the most frequently inherited hematologic diseases globally,  with sickle cell anemia being its most common and severe form.

Among the many manifestations of this disease is renal dysfunction, characterized by chronic kidney disease, impaired urinary concentrating ability, blood in urine (haematuria), and increased risks of urinary tract infections. Ultimately, these conditions could result in polyuria, commonly seen in sickle cell disease.

11. Lifestyle

Taking large amounts of caffeine and alcohol may increase the amount of urine an individual produces and lead to frequent urination. A research study published in 2011 suggests that caffeine, when taken at 4.5mg/kg or above, can cause polyuria in individuals, especially patients with an overactive bladder.

Alcohol, on the other hand, has been reported to increase thirst and promote oral dryness. This thirst and oral dryness prompt you to consume more fluids, which causes polyuria during the alcohol-induced hangover.

Nocturia

Simply put, nocturia is the consistent, frequent urge to urinate at night. This condition is said to affect 65% of adults over the age of 50. Research studies claim that 24% of individuals over the age of 65 will have two or more nocturia episodes per night.

Frequent nighttime urination can lead to long-term sleep deprivation, mood swings, fatigue, cognitive dysfunction, and lethargy, decrease productivity, and increase the risk of falls and injuries at night.

Causes of Nocturia

There are four leading causes of nocturia, and they include: 

• Increased production of urine at night: This is known as nocturnal polyuria and is characterized by making more than 20% of your 24-hour urine output at night, or over 33% in older adults. Nocturnal polyuria is common, accounting for  88% of all nocturia complaints. It is associated with congestive heart failure, obstructive sleep apnea, and the evening use of diuretics.
• Overproduction of urine throughout the day: This is known as global polyuria and typically results in a urinary output of more than 40 mL/kg per 24 hours. Global polyuria is associated with increased water intake due to health conditions like diabetes mellitus or diabetes insipidus.
• Bladder storage problems: People who wake up multiple times at night to urinate without any apparent cause of polyuria might have bladder problems like small bladder volume and overactivity of the bladder muscle. Excessive consumption of caffeine and alcohol, enlarged prostates in older men, or post-menopausal changes in women can all cause bladder storage problems.
• Sleeping disorders: Sleeping disorders like insomnia can cause you to wake up multiple times at night to pass urine. Studies have shown that 50% of patients with obstructive sleep apnea would experience nocturia. This is linked to the increased production of atrial natriuretic peptide (ANP) (a diuretic hormone produced by cells of cardiac muscles), resulting in more urine production at night.

Associated symptoms of frequent urination

Specific symptoms can be associated with polyuria. These symptoms include:

• Polydipsia (increased/excessive thirst) 
• Fatigue
• Dehydration
• Nocturia
• Weight loss

These symptoms may also indicate other underlying illnesses. Therefore, if you experience all these symptoms together, you should book an appointment with your primary healthcare provider. 

Treatment for frequent urination

Treatment for polyuria differs for various patients. This is due to the fact that there are numerous conditions that can cause polyuria.

Your doctor will help you diagnose the cause of your polyuria and determine the proper course of treatment. 

Tips for preventing frequent urination

Here are some useful suggestions to help you manage polyuria if there are no underlying medical conditions. 

• Don’t take too much fluid close to bedtime. 
• Watch your overall fluid intake.
• Reduce your daily caffeine and alcohol intake, especially if you have an overactive bladder. 

When to seek medical help

If you’ve been urinating more frequently than usual, you might want to seek medical advice from your doctor. A urologist can help investigate and diagnose why you’re experiencing polyuria, especially if it’s getting in the way of your usual daily activities. 

On the other hand, if your polyuria is unrelated to any medical condition, simply applying lifestyle tips like watching your water intake and limiting caffeine might help. 

Closing remarks

Frequent urination, or polyuria, often means your body makes more urine than usual. This could be because you’ve been drinking more water, but it may also indicate more severe health problems. 

Medical conditions that impair kidney function, like diabetes mellitus, diabetes insipidus, and sickle cell disease, can cause polyuria. Frequent urination is also more common during pregnancy and in the elderly. 

Frequent urination at night, known as nocturia, could be caused by a generalized increase in urine output (global polyuria) or increased urine production at night (nocturnal polyuria). It may also be due to bladder problems or sleep disorders. 

Simple lifestyle changes like limiting water, alcohol, and caffeine intake can help manage polyuria unrelated to any disease. Nevertheless, you should consult a health provider if polyuria is disrupting your life.