What Is Nocturnal Polyuria (Nocturia)?
Having a consistent bedtime routine and reducing your fluid intake might reduce how much you urinate at night.
Medically reviewed by Jamin Brahmbhatt, MD
Nocturnal polyuria is voiding a high urine volume at night. Some people confuse nocturnal polyuria with nocturia, or frequent nighttime urination, though your bladder is not actually full. Instead, nocturnal polyuria is a common cause of nocturia. Nocturnal polyuria affects about 88% of people with nocturnia, which includes nearly 50 million people in the U.S.
Nocturnal polyuria is a natural part of aging. The symptom often occurs with health conditions like diabetes and heart and kidney problems. A healthcare provider can diagnose nocturnal polyuria by asking you to keep track of how much urine you expel at night. A volume greater than 20% to 33% of your overall 24-hour urine volume may signal nocturnal polyuria.
At what point does waking up frequently at night to pee signal a larger problem, and what can you do about it? Read on to learn what nocturnal polyuria is, including symptoms, causes, ways to cope, and more.
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Nocturnal Polyuria Symptoms
Polyuria, or frequent voiding due to a high volume of urine, is a symptom of diabetes, heart and kidney problems, and other age-related conditions, S. Adam Ramin, MD, a urologist based in Los Angeles, told Health. Nocturnal polyuria simply means urinating a lot during the evening or nighttime hours.
According to Dr. Ramin, you may have nocturnal polyuria if you:
Have daytime polyuria
Have health conditions that cause excess fluid build-up or increase urine production
Take medications with a diuretic effect
Void substantial amounts of urine each time
Wake up frequently at night to urinate, or more than twice per evening
Related: What Is Polyuria—And Why Do I Pee So Much?
What Causes Nocturnal Polyuria?
Polyuria has to do with the position of your body while you sleep. The supine, or lying down, position often leads to excess fluids recycling back through your kidneys. That fluid turns into urine in a process known as "third spacing," Mark Ellerkmann, MD, a urogynecologist based in Baltimore, told Health.
Many people with polyuria frequently urinate during daytime and nighttime hours. Still, some only have it in the evening: "If you have polyuria during the daytime, you'll have it at nighttime, as well. However, there is a subset of people who only have nocturnal polyuria," said Dr. Ramin.
Having an abnormally high amount of fluid in your body due to a health condition means you may only have polyuria in the evening since you are lying down. The same thing can happen to people who spend hours every day on their feet, said Dr. Ellerkmann.
Risk Factors
Factors that increase your risk of nocturnal polyuria are the same as they are for polyuria. Nocturnal polyuria is not a separate condition but the timing of when you have symptoms.
Those factors include:
An imbalance of calcium
Certain medications (e.g., diuretics and lithium)
Chronic venous insufficiency, which causes the veins in your legs to not allow for proper blood flow
Diabetes
Diabetes insipidus, which causes your body to produce excess urine
Drinking too much alcohol, caffeine, or water
Sickle cell disease, which causes C-shaped red blood cells that impair blood flow
Sleep disorders like sleep apnea
Age also plays a big role in nocturnal polyuria. Some hormones decrease as you get older. For example, older adults have low levels of the hormone vasopressin, which usually suppresses urine production at night. Certain health conditions that link to polyuria are more common in older adults than others.
"Older men who have an enlarged prostate but also have cardiac problems, like hypertension, are likely to have nocturnal polyuria," said Dr. Ramin. "Women with an overactive bladder may also have other conditions like diabetes, congestive heart failure, and varicose veins."
How Is Nocturnal Polyuria Diagnosed?
It's essential to see a healthcare provider to diagnose nocturnal polyuria and determine the cause. One of the easiest ways to do this is with a 24-hour voiding diary. You'll measure how often you urinate and how much. Keeping a careful log in the evening can help a healthcare provider confirm nocturnal polyuria.
Nighttime urine volume greater than 20% to 33% of your overall 24-hour urine volume may indicate nocturnal polyuria. For example, you might have nocturnal polyuria if you produce 3,000 milliliters of urine in a 24-hour period but pass 990 milliliters or more at night.
In addition to performing a physical exam, a healthcare provider may use diagnostic tests like:
Cystoscopy: This procedure allows a healthcare provider to look inside your bladder and urethra.
Lab tests: A healthcare provider might want to check your A1C and glucose levels to rule out diabetes. They might also check your serum electrolytes and renal function. Urinary osmolality measures how much chloride, potassium, sodium, and urea are in your urine.
Urodynamics: This is a set of tests examining how well your bladder and urethra work.
Treatments for Nocturnal Polyuria
You do not need to treat nocturnal polyuria unless it significantly interferes with your sleep. There are a couple of options that might reduce how much urine you produce at night.
Treat the Underlying Cause
It's important to know what's causing your body to produce excess amounts of urine. You may not be able to discern that for yourself. A healthcare provider can identify the source of your problem and what treatments may work best. For example, some evidence suggests that using a continuous positive airway pressure (CPAP) machine nightly reduces your urination if you have obstructive sleep apnea.
You might work with a healthcare provider to time when you take your medications. Research has shown that taking a diuretic midday, instead of before bed, reduces nocturnal polyuria.
Use an Antidiuretic
Desmopressin, a neuropeptide that mimics the body's production of hormones like vasopressin, might treat nocturnal polyuria. Research has found that desmopressin is an effective treatment, especially if you take it about one hour before bedtime. A healthcare provider will monitor your use to avoid hyponatremia, or serum sodium levels. Hyponatremia can be fatal if untreated.
How To Prevent Nocturnal Polyuria
It might be difficult to prevent nocturnal polyuria. Increased urine production at night is a common cause of nocturia, which is a natural part of aging. Still, there are some ways that you might be able to reduce the number of times you get up to go to the bathroom.
Prevention includes:
Avoid standing for long periods.
Do not drink fluids within two to three hours before bedtime.
Elevate your legs or use support hose before bedtime.
Limit your daily fluid intake to two liters per day.
Make a consistent bedtime.
Reduce your protein and salt intake.
Regularly exercise but not too close to bedtime.
Take time to unwind 20–30 minutes before bedtime. Do breathing exercises, listen to calming music, practice some yoga, read, or take a warm bath.
Try pelvic floor exercises.
Complications
Nocturnal polyuria might affect your sleep quality. One of the most common complications is sleep deprivation, which causes decreased cognitive function, fatigue, and mood changes. Older adults with sleep deprivation have an increased risk of falls, which may result in injuries.
Experts have linked sleep deprivation to other complications, such as:
Depression
Diabetes
Heart and kidney disease
High blood pressure
Obesity
Stroke
Living With Nocturnal Polyuria
Nocturnal polyuria may impact your quality of life if it interferes with how well you sleep. It's essential that you reach out to a healthcare provider if nocturnal polyuria affects your physical and mental health.
They may advise some ways to cope, including:
Absorbent underwear
Cleansing cloths, lotions, and soaps that prevent skin irritation if you experience bedwetting
Leg elevation
Mattress covers
Naps during the afternoon
Reduced fluid intake
Support hose
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