Why Do I Make Humming Noises In My Sleep? The Reason

Waking up to a strange sound — or having your partner tell you about it — can be unsettling. If that sound is a steady, low-pitched hum, you likely want a clear answer about what is happening. Most often, humming noises during sleep are caused by a condition called catathrenia, a rare breathing disorder where you hum or groan while exhaling. The sound is usually harmless, but it can disrupt your sleep and your partner’s, so understanding the cause is the first step toward managing it.

What Is Catathrenia and How Is It Different From Snoring?

Catathrenia is the medical term for groaning or humming sounds made during sleep. It is a type of parasomnia, which is a category of sleep disorders involving unwanted events during sleep. The key feature is that the sound happens during exhalation — when you breathe out.

Snoring, by contrast, happens during inhalation — when you breathe in. This is the most straightforward way to tell the two apart. Snoring is caused by air struggling to pass through a narrowed airway. Catathrenia involves a slow exhale against a partially closed voice box, which produces the humming tone. Some people describe the sound as a long, monotonous groan or a high-pitched hum. It can last anywhere from a few seconds to over a minute.

Catathrenia is not dangerous in itself. It does not appear to cause oxygen drops or heart strain like obstructive sleep apnea does. But it can be loud enough to wake a bed partner, and it can occasionally interrupt your own sleep, leaving you feeling tired during the day.

Why Do I Make Humming Noises In My Sleep? The Reason Explained

The exact reason catathrenia happens is not fully understood. What is known is that it involves a specific pattern of breathing. During the sound, you take a slow, deep breath in, then exhale very slowly while partially closing the vocal cords. The air passing through that narrow opening creates the humming vibration.

Research suggests this may be a learned breathing pattern or a subtle brainstem issue that affects how the breathing muscles coordinate during sleep. Some studies have found that catathrenia occurs most often during REM sleep, the stage where dreaming happens. This is a strong clue because REM sleep naturally suppresses muscle tone, and the muscles that keep the airway open may behave differently during this stage.

Catathrenia is rare. It is not a sign of a serious underlying illness, and it is not linked to emotional or psychological problems. It is a mechanical quirk of breathing during sleep, not a response to stress or unresolved feelings. If you are the one making the sound, you likely have no idea it is happening unless someone tells you or you hear a recording.

Who Gets Catathrenia and When Does It Start?

Catathrenia can appear at any age, but it is most commonly reported in young adults and middle-aged people. Some research suggests it may be slightly more common in men, though the evidence is not strong enough to state this with certainty. It is not a condition you are born with, and it does not run clearly in families.

Unlike some sleep disorders that appear suddenly, catathrenia often develops gradually. People may have it for years before it is noticed, simply because it rarely wakes the person making the sound. Most people who seek help do so because a partner mentions the noise or because they feel unrefreshed in the morning.

There is no evidence that catathrenia is linked to any particular personality type, mental health condition, or lifestyle habit. It is not caused by alcohol, caffeine, or eating before bed, though these can affect sleep quality in other ways. If you are wondering whether something you are doing is causing the hum, the honest answer is that no reliable evidence points to a specific trigger.

When Should You See a Doctor About Sleep Humming?

If the humming is occasional and quiet, it may not require medical attention. But you should consider a medical evaluation if the sound is loud enough to disturb your partner, if you regularly wake up feeling exhausted, or if you notice gasping, choking, or pauses in breathing during the night.

Those additional symptoms could point to obstructive sleep apnea, which is a different and more serious condition. Sleep apnea involves repeated pauses in breathing during sleep, often followed by a gasp or snort. It causes oxygen levels to drop and can strain the heart over time. If you have any suspicion that your breathing is stopping during sleep, do not brush it off. This requires proper testing.

A doctor will usually start with a careful history. They will ask about your sleep habits, your partner’s observations, and any daytime sleepiness. If catathrenia is suspected, the definitive test is an overnight sleep study, called polysomnography. This test records your brain waves, breathing, oxygen levels, heart rate, and muscle activity while you sleep. It can confirm whether the hum is catathrenia or something else, and it can rule out sleep apnea.

Is There a Treatment for Catathrenia?

There is no standard treatment for catathrenia, and that is the honest truth. Because the condition is rare and generally harmless, most doctors do not treat it aggressively. If it is not affecting your sleep quality or your relationship, the most reasonable approach may be to simply be aware of it and not worry.

Some case reports and small studies have described improvement with a breathing technique called continuous positive airway pressure, or CPAP. This is the same machine used for sleep apnea. It delivers a steady stream of air through a mask to keep the airway open. Some people with catathrenia have reported that CPAP reduces or eliminates the humming, but the evidence is limited to small studies and individual cases. It is not a guaranteed fix, and it is not approved specifically for catathrenia.

Other treatments that have been tried include speech therapy to retrain breathing patterns and certain medications, but none have been studied in large trials. No medication is approved for catathrenia. If a clinician suggests a treatment, it is reasonable to ask what evidence supports it and what the expected benefit might be.

If the sound is only bothering your partner, practical steps can help. A white noise machine, earplugs, or sleeping in separate rooms can reduce the impact. These do not treat the condition, but they address the real-world consequence of it.

What If It Is Not Catathrenia?

Not every nighttime noise is catathrenia. Several other conditions can produce sounds during sleep, and it is worth knowing the difference.

Snoring is the most common. It happens on the inhale and is often louder with certain sleep positions, especially on your back. It can be a sign of sleep apnea, so it deserves attention if it is loud and persistent.

Sleep talking can sound like mumbling, and occasionally it can have a humming quality. It usually happens during lighter sleep stages and is generally harmless.

Bruxism, or teeth grinding, produces a grinding or clacking sound rather than a hum. It can cause jaw pain and tooth damage, and it is worth addressing with a dentist.

Seizures during sleep are rare, but they can produce unusual vocalizations. If the sound is accompanied by jerking movements, confusion, or wetting the bed, this is a medical emergency that requires immediate evaluation.

If you are unsure what the sound is, a sleep study is the most reliable way to find out. Recording the sound at home with a phone can also help your doctor understand what is happening.

Does Catathrenia Affect Your Health Long Term?

Current evidence does not show that catathrenia causes long-term health problems. It is not associated with heart disease, cognitive decline, or any other chronic condition. The main consequences are social — a disturbed bed partner — and potentially sleep quality if the sound is frequent enough to cause micro-arousals.

Some people with catathrenia report waking up with a dry throat or a mild headache, but these are not consistently reported symptoms. The condition does not appear to worsen over time, and some people find that it comes and goes without any clear pattern.

The most important thing is to distinguish catathrenia from sleep apnea. Sleep apnea is a serious condition with real long-term risks, including high blood pressure, heart disease, and stroke. If there is any doubt about which condition you have, a sleep study is the only way to be sure. Do not assume a humming sound is harmless until you have confirmed that your breathing is not pausing during the night.