Sleep Apnoea and Nocturia: The Hidden Connection

Waking up several times a night to urinate—known medically as nocturia—is commonly attributed to prostate issues, ageing, fluid intake, or bladder conditions. However, an often overlooked and highly treatable cause is obstructive sleep apnoea (OSA).

For many patients, nocturia is not a urological problem at all, but a sleep-related breathing disorder.

What Is Nocturia?

Nocturia is defined as waking one or more times during the night to pass urine. While occasional nocturnal urination can be normal, waking two or more times per night on a regular basis is abnormal and is associated with:

• Poor sleep quality

• Daytime fatigue

• Reduced concentration

• Increased risk of falls (particularly in older adults)

Importantly, nocturia should not be dismissed as a normal part of ageing.

What Is Obstructive Sleep Apnoea?

Obstructive sleep apnoea is a common condition in which the upper airway repeatedly collapses during sleep, leading to:

• Intermittent pauses in breathing

• Drops in oxygen levels

• Frequent micro-arousals from sleep

Many patients are unaware these events are occurring, but the physiological consequences are significant.

How Sleep Apnoea Causes Nocturia

The link between sleep apnoea and nocturia is well established and involves several physiological mechanisms:

1. Increased Atrial Natriuretic Peptide (ANP)

During apnoeic episodes, the chest works harder to breathe against a blocked airway. This increases pressure within the heart, triggering the release of atrial natriuretic peptide, a hormone that signals the kidneys to excrete salt and water. The result is increased urine production overnight.

2. Sleep Fragmentation

Repeated arousals from sleep make individuals more aware of bladder sensations that would normally be ignored during deep sleep. Patients may wake “to urinate” when in fact the awakening was caused by an apnoea event.

3. Hypoxia-Driven Hormonal Effects

Low oxygen levels during sleep apnoea can disrupt normal antidiuretic hormone regulation, further contributing to nocturnal urine production.

Key Clues That Nocturia May Be Sleep-Related

Nocturia is more likely to be related to sleep apnoea if it occurs alongside:

• Loud or habitual snoring

• Witnessed breathing pauses during sleep

• Unrefreshing sleep

• Excessive daytime sleepiness

• Morning headaches

• Hypertension or atrial fibrillation

• Obesity or increased neck circumference

Notably, many men undergo prostate treatment with little improvement in nocturia because the underlying sleep apnoea has not been addressed.

Does Treating Sleep Apnoea Improve Nocturia?

Yes. Effective treatment of obstructive sleep apnoea—most commonly with CPAP therapy—has been shown to significantly reduce nocturia frequency, often within weeks.

Patients frequently report:

• Fewer night-time awakenings

• Improved sleep continuity

• Better daytime energy and concentration

In some cases, nocturia resolves completely once sleep apnoea is adequately treated.

When Should You Be Assessed?

You should consider a sleep assessment if you:

• Wake two or more times per night to urinate

• Have persistent nocturia despite urological treatment

• Snore loudly or feel unrefreshed despite adequate sleep time

A sleep study can determine whether sleep apnoea is contributing to your symptoms.

Take-Home Message

Nocturia is not always a bladder or prostate problem. For many patients, it is a key symptom of undiagnosed obstructive sleep apnoea. Identifying and treating sleep apnoea can dramatically improve night-time urination, sleep quality, and overall health.

If nocturia is affecting your sleep or quality of life, a comprehensive sleep assessment may be the missing piece.