Causes of Frequent Urination at Night

Nocturia is the medical term used to describe the need to get up frequently at night to urinate. It is a condition that people commonly attribute to older age, but there are other reasons why it can occur. Some causes are benign and readily resolved with lifestyle changes; others may be persistent or signs of a serious illness.

Chronic nocturia can significantly affect a person's well-being and quality of life, causing sleep deprivation, daytime fatigue, impaired concentration, depression, and a loss of productivity.

Physiology

Older age is one of the primary factors associated with nocturia, with the majority of cases affecting people over the age of 60. There may be multiple causes for this, but one of the prime reasons is a condition known as nocturnal polyuria (NP) in which high volumes of urine are produced during sleep.

The size of a person's bladder also plays a large role in the risk of nocturia. This is especially true in younger people, in whom the volume of urine produced at night can often exceed the organ capacity.

Diet

The need to urinate at night may be diet-related, triggering nocturia either directly (by stimulating the production of urine) or indirectly (by compressing the bladder). Among some of the more common dietary causes are:

• Alcohol and caffeine: Both have diuretic properties that stimulate urine production.
• Dietary salt: Excessive salt (sodium) can trigger nocturia in people with obesity or poor cardiac output. Sodium increases fluid retention, the fluid of which may only be released at night when the bladder is full.
• Hyperhydration: Simply drinking too much water before bedtime is enough to trigger a middle-of-the-night bathroom visit.
• Low-fiber diet: Chronic constipation is a common consequence of a diet low in dietary fiber. At night, the buildup of stool can cause the bowel to distend, placing direct pressure on the bladder.

Pregnancy

Nocturia can occur during all stages of pregnancy but often for very different reasons. The times during which nocturia is common include:

• Early pregnancy: In early pregnancy, women often feel the need to urinate at night as rising progesterone levels promote bloating and water retention. In some cases, nocturia may be an early sign of pregnancy.
• Later pregnancy: During the second and third trimesters especially, it is not uncommon for women to experience frequent urination as the womb compresses the bladder. At night, certain body positions can intensify the compression and trigger nocturia.
• After pregnancy: Women will sometimes develop bladder and pelvic organ prolapse after delivery, both of which can exert pressure on the urinary tract.

Medications

Nocturia may be caused by the medications you take. In some cases, a drug may promote the release of acetylcholine, a compound that affects the system and can provoke bladder contractions.

At other times, it may impair the release of norepinephrine, a hormone that helps direct the relaxation of smooth muscles, including those of the bladder. Other drugs simply have a diuretic effect.

Some of the drugs commonly associated with nocturia include:

• Darvon (propoxyphene)
• Declomycin (demeclocycline)
• Dilantin (phenytoin)
• Diuretics, such as Lasix (furosemide)
• Lanoxin (digoxin)
• Lithium
• Penthrox (methoxyflurane)

The excessive use of vitamin D can also promote nighttime urination.

Acute Conditions

Nocturia may occur in tandem with an acute condition involving the urinary tract. The urologic conditions include:

• Bladder stones
• Interstitial cystitis (bladder infection)
• Kidney stones
• Pyelonephritis (kidney infection)
• Urinary tract infection (UTI)

With conditions like these, inflammation can trigger urinary urgency (the sudden need to urinate due to contractions with the urinary tract). Nocturia is often an extension of urinary urgency during the day. Once the cause of the inflammation is treated, the nocturia will almost invariably resolve.

Chronic Conditions

Nocturia may also be the result of a chronic condition and, as a result, may persist and be harder to resolve. Some of the causes are urologic and others aren't. The most common include:

• Benign prostatic hyperplasia (BPH)
• Bladder cancer
• Chronic heart failure (CHF)
• Diabetes
• Hypertension
• Multiple sclerosis (MS)
• Overactive bladder (OAB)
• Parkinson's disease (PD)
• Sleep apnea

Nocturia may be associated with reduced cardiac output and increased fluid retention, such as occurs with CHF. Hypertension and sleep apnea can both exert pressure on the heart and stimulate the release of a compound called atrial natriuretic peptide (ANP) that triggers the release of sodium and water.

Other conditions cause nocturia by compressing the bladder (BPH), reducing the capacity of the bladder (bladder cancer), or overstimulating the bladder (MS, OAB, PD). Elevated blood sugar levels also promote nighttime urine production.

A Word From Verywell

Nocturia may be considered a "sign of age" to some people, but it should never be ignored if it is severe and interfering with your ability to get a good night's rest. In some cases, it can be a sign of something that is either serious or imminently treatable. In younger people, nocturia should never be ignored.