Excessive Urination at Night (Nocturia)

What counts as nocturia

Most adults can sleep 6 to 8 hours without needing to pee, because the body releases more antidiuretic hormone (vasopressin) at night, which concentrates urine. Nocturia is any waking to pass urine, with each void preceded and followed by sleep. Getting up once a night is common over age 60. Getting up 2 or more times is linked to poorer sleep, daytime tiredness and falls in older adults, and often signals a treatable cause.

Nocturia differs from bedwetting (passing urine while asleep) and from daytime frequency, though they often occur together.

Causes of excessive urination at night

Making too much urine at night (nocturnal polyuria)

When more than about a third of the day's urine is produced at night in older adults (a fifth in younger adults), it is called nocturnal polyuria. Causes include:

• Evening fluids, especially caffeine (coffee, tea, cola, energy drinks) and alcohol, which both increase urine output
• Fluid in the legs: swelling from heart failure, venous insufficiency, low protein or some medicines (such as amlodipine) collects in the legs by day. Lying down returns it to the circulation and the kidneys excrete it at night.
• Obstructive sleep apnea: pauses in breathing strain the heart, which releases a hormone (natriuretic peptide) that makes the kidneys produce more urine
• Diuretics taken in the afternoon or evening
• Reduced night-time vasopressin, common with age

Making too much urine all day (global polyuria)

• Diabetes: high blood sugar spills into the urine and pulls water with it, causing thirst and frequent urination day and night
• Diabetes insipidus: a rare lack of, or resistance to, vasopressin
• High calcium levels
• Drinking large volumes (for example, more than 3 liters a day), including psychogenic polydipsia
• Lithium and some other medicines

Reduced bladder capacity

• Benign prostatic hyperplasia: an enlarged prostate narrows the urethra, so the bladder never empties fully and fills quickly. Weak stream, hesitancy, dribbling and urgency are typical.
• Overactive bladder: sudden strong urges and frequency by day and night
• Urinary tract infection: burning, urgency and frequency
• Interstitial cystitis, bladder stones, bladder cancer, pelvic radiotherapy
• Pregnancy: the growing uterus presses on the bladder, and fluid shifts at night
• Menopause: thinning of the urethral and bladder lining increases urgency

Sleep problems

Insomnia, pain, restless legs, anxiety and depression make people wake, and once awake they notice the bladder. Sleep apnea causes both waking and extra urine production.

Clues to the cause

How doctors diagnose nocturia

• Bladder diary (frequency-volume chart): for 3 days, record the time and amount of every drink and every void, plus bedtime and waking time. This is the most useful single test, separating nocturnal polyuria from small bladder capacity.
• Urine test: for glucose, blood and infection.
• Blood tests: blood sugar or HbA1c, kidney function, calcium, sodium, and sometimes BNP for heart failure.
• Prostate examination and PSA discussion in men.
• Bladder scan after voiding to check for incomplete emptying.
• Sleep study if sleep apnea is suspected.
• Medicine review, including timing of diuretics.

Treatment and what helps

Self-help

• Stop drinking 2 to 3 hours before bed, but keep total daily intake normal (about 1.5 to 2 liters for most adults unless told otherwise).
• Avoid caffeine after midday and limit alcohol in the evening.
• If your ankles swell, raise your legs above heart level for an hour or two in the afternoon or evening, or wear compression stockings during the day. This moves fluid out before bed.
• Empty your bladder just before sleep, and try double voiding (pee, wait a minute, then try again).
• Make the route to the toilet safe and lit to prevent falls.

Medical treatment

• Change timing of diuretics to the morning or early afternoon, with your doctor's guidance.
• Overactive bladder: bladder training, pelvic floor exercises, and medicines such as antimuscarinics or beta-3 agonists.
• Enlarged prostate: alpha-blockers, 5-alpha-reductase inhibitors, or procedures to reduce prostate size.
• Sleep apnea: CPAP often reduces nocturia markedly.
• Diabetes and heart failure: better control of the underlying condition.
• Desmopressin: a synthetic vasopressin that reduces night-time urine production in selected adults with nocturnal polyuria. It can cause low sodium, especially in people over 65, so blood sodium is monitored.

Frequently asked questions

Why do I pee so much at night?

Common reasons include drinking fluids, caffeine or alcohol in the evening, an enlarged prostate, overactive bladder, leg swelling that returns to the circulation when you lie down, diabetes, heart failure and sleep apnea. A 3-day bladder diary usually shows which is responsible.

How many times is it normal to pee at night?

Most younger adults do not need to wake to pee. Getting up once a night is common and usually normal over age 60. Waking 2 or more times a night regularly is considered bothersome nocturia and is worth discussing with a doctor.

Is nocturia a sign of diabetes?

It can be. Undiagnosed or poorly controlled diabetes causes thirst and frequent urination day and night, often with tiredness and weight loss. A simple urine or blood sugar test can check. Most nocturia, however, has other causes such as evening fluids or prostate enlargement.

Can sleep apnea cause frequent urination at night?

Yes. Breathing pauses in sleep apnea strain the heart, which releases a hormone that makes the kidneys produce more urine. People with sleep apnea often wake several times to pee, and treatment with CPAP frequently reduces night-time urination.

What is the best treatment for nocturia?

It depends on the cause. Cutting evening fluids, caffeine and alcohol, raising swollen legs in the evening and moving diuretic doses earlier help many people. Treating an enlarged prostate, overactive bladder, diabetes or sleep apnea helps others. Desmopressin is used in selected cases with monitoring.