Nocturnal Polyuria

John Tiong, MPharm, PhD, RPh

Nocturnal polyuria is defined as the production of an abnormally large volume of urine during sleep. The measurement includes the total urine produced after going to bed, taking into account the first void after rising. [International Continence Society]

   “This is the third time tonight I am waking up to pee!
Will I ever get a proper sleep? I am so tired everyday!
At this rate, I am going die of fatigue” 

Does it ring a bell with you? If you often experience this, you may have a condition known as nocturia. Unlike enuresis, (also known as bed-wetting) where an individual does not arouse from sleep even when the bladder is full, patient with nocturia frequently wakes up at night due to bladder-voiding urge. Contrary to common belief, nocturia is not just a disease of the elderly men. In fact, nocturia can affect both male and female of all age groups although the disease does become more common with age [1,2]. Moreover, it is not just another lifestyle issue since sleep loss in the long run can actually lead to numerous insidious health complications.



“What is wrong with me?

    The need to wake up to pee boils down to two key factors:

    1. Bladder storage problem -
      Often linked to prostate enlargement in male and/or overactive bladder.
    2. Excessive urine production at night
      Also known medically as nocturnal polyuria, it has been shown by studies to be the most common cause of nocturia [3,4].

    It is worth pointing out that these conditions are not mutually-exclusive. In other words, it is possible for patients to concurrently have both bladder storage problem as well as excessive nightly urine production issue.


    What could be the reasons for nocturnal polyuria?

    While habits such as caffeine consumption or fluid over-consumption in the late evening/at night can lead to nocturnal polyuria, excessive urine production at night can also be a manifestation of other underlying medical issues such as heart failure, sleep apnea  and/or  disrupted production of anti-diuretic hormone which is involved in limiting water excretion through the kidney [5].


    How much urine is too much? Do I have nocturnal polyuria?

    In a normal individual, 24-hour urine production takes place predominantly during the day. When the night time urine production exceeds 20-30% of the total daily urine output (age-dependent), one is said to be suffering from nocturnal polyuria [6].

    More often than not, a proper diagnosis can be made through a detailed medical check-up in conjunction with the use of a voiding diary (example as shown below): 


    1. Bosch JL & Weiss JP. J Urol 2010;184:440–446; 2. Weiss JP et al. BJU Int 2013;111:700–716
    2. Weiss JP et al. J Urol 2011;186:1358–1363;
    3. Chang SC et al. Urology 2006;67:541–544
    4. Asplund R. Gen Pharmacol.1995 Oct;26(6):1203-9.
    5. Van Kerrebroeck P et al. Neurourol Urodyn 2002;21:179–183