What Is Catathrenia? Nocturnal Groaning Explained
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is catathrenia?
Catathrenia is a sleep-related breathing disorder that causes moaning or groaning while exhaling during sleep, lasting from a couple of seconds up to 40 seconds. [4] A bed partner usually notices it first. The exact cause is unknown. [4] It is not dangerous to physical health but can affect sleep quality, mood and relationships. [4] Oral appliances and CPAP machines are treatment options. [4] [6]
What the research says
The groan comes from the vocal cords, and daytime sleepiness shows up in about a third of cases. A 2024 systematic review concluded the sound is produced by the vocal cords, is associated with excessive daytime sleepiness in about one-third of cases, and that the cause and best treatment of the typical form are still unknown (Martel et al., Sleep Med Rev, 2024) [1].
Treatment response depends on the type of catathrenia. In a cohort of 66 patients diagnosed by overnight audio/video polysomnography who sought treatment with a mandibular advancement device or CPAP, patients with smaller upper airways and more breathing-related arousals (n=49) responded better to treatment than the other group (n=17): 82.6% versus 41.2% (Yu et al., Nat Sci Sleep, 2024) [2].
It is not linked to physical harm, but it can disturb sleep. A review of 15 case reports and 17 case series describing 191 patients, plus questionnaires from 47 people with catathrenia, found no association with risk of physical harm, although the groaning disturbs bed partners and has been linked to unrefreshing sleep and fatigue (Alonso et al., J Clin Sleep Med, 2017) [3].
Key takeaways
Catathrenia causes loud moaning or groaning during sleep that happens on the exhale, lasts up to 40 seconds, and can occur nightly in both REM and non-REM sleep. [4]
Your bed partner usually notices first, because most people never hear themselves groaning as it happens. [5]
The exact cause is unknown, but research points to malfunctioning nerve cells in the brain's respiratory center causing prolonged exhaling. [4]
It is not dangerous to your physical health, though it can harm sleep quality, mental health, and social well-being. [4]
Treatments work: oral appliances, CPAP machines, and surgical evaluation can reduce or eliminate nightly groaning for many people. [4]
What Is Catathrenia?
Catathrenia is a sleep-related breathing disorder that causes moaning or groaning during sleep. The noise happens as you exhale. It is loud and lasts for a couple of seconds or up to 40 seconds. [4] It can happen nightly, during both REM (rapid eye movement) sleep and non-REM sleep. [4]
Nocturnal groaning may wake you up. But most often, you will not notice or hear yourself as it happens. Your sleeping partner or someone within your household is usually the first to tell you that they heard you. In the morning, you may feel like you did not get a full night's rest.
How Common Is Catathrenia?
Two studies in different parts of the world calculated that catathrenia is uncommon. It affects 0.17% of people (25 of 15,052 people over 10 years) in Japan and 0.4% of people (4 of 1,004 people in one year) in Norway. [4] The frequency may be underreported because many people do not realize they have the condition or mention it to their healthcare provider. Catathrenia may also be mistaken for snoring. [4]
Symptoms and Causes
What Are the Symptoms of Catathrenia?
The main symptom of catathrenia is moaning or groaning during sleep. It happens when you exhale and stops when you inhale. [4]
Sound Characteristic | Description |
Loud | Audible to anyone in the room, often waking a bed partner |
Monotone | A steady, unvarying pitch |
Sexual | Can sound intimate, causing embarrassment |
Gloomy | A deep, mournful tone |
Humming | A continuous humming vibration |
Cracking | A cracking quality to the sound |
Ending with a grunt or sigh | The groan may finish with a grunt or a sigh |
This symptom typically occurs nightly. While many people with catathrenia do not have any sleep-related complaints, some may report snoring, mouth breathing, and sleep interruptions. [4]
In the morning, you may experience fatigue, grogginess, dry mouth, a hoarse voice, a sore throat, a headache, and difficulty concentrating. [4]
Morning symptoms happen because of the breathing technique used when sleeping (using your mouth only). They also affect your quality of sleep. You may sleep lighter or wake up often during the night. [4]
What Causes Catathrenia?
The exact cause of catathrenia is unknown. [4] Research suggests it could happen due to malfunctioning neurons (nerve cells) in your brain at the respiratory center, known as the medulla oblongata. These neurons cause prolonged exhaling. When you exhale, your vocal cords vibrate to create a moaning or groaning sound. [4]
Can Anxiety Cause Catathrenia?
It is not clear if anxiety causes catathrenia. Studies are still ongoing to learn more and to determine if other conditions like stress can trigger symptoms. [4]
Is Catathrenia Hereditary?
Current research suggests you are more at risk of nocturnal groaning if someone in your biological family also has this condition. [4]
Is Catathrenia Dangerous?
Catathrenia is not dangerous to your physical health, but it can affect how well you sleep (sleep quality) and your interpersonal relationships. [4] Catathrenia can cause stress or social embarrassment. [4] It can be frustrating not to be in control of the noises your body makes as you sleep. As a result, you might avoid certain situations like overnight stays with others to prevent them from hearing you.
Catathrenia vs. Snoring
Catathrenia and snoring are both noises you can make during sleep, but they come from different mechanisms.
Feature | Catathrenia | Snoring |
Breathing phase | Happens as you exhale | Happens as you inhale |
Sound source | Larynx (voice box) | Pharynx (throat) |
Sound quality | Moaning or groaning, up to 40 seconds | Rattling, snorting, or vibrating sound |
Sleep stage | Occurs in REM and non-REM sleep | Varies |
Awareness | You rarely hear yourself | May or may not be noticed |
Diagnosis and Tests
How Is Catathrenia Diagnosed?
A healthcare provider will diagnose catathrenia after a clinic visit, which will include taking a medical history to ask about signs and symptoms, a physical exam, and possibly further testing. [4] Your provider will ask how you feel when you wake up and what other people have heard or observed while you are sleeping.
If possible, record yourself sleeping so your provider can play back the audio and listen. This can help them rule out other conditions like sleep talking or snoring. [4]
A primary care physician may refer you to a sleep specialist (somnologist). You may need to participate in a sleep study (polysomnogram). This overnight test at a sleep center monitors your brain activity, breathing, and how other body systems work as you sleep. [4]
Management and Treatment
How Is Catathrenia Treated?
Catathrenia does not always require treatment. [4] However, a healthcare provider may recommend one or a combination of the following treatments:
Treatment | How It Works |
Oral appliances | Wearing an oral appliance (like a retainer) keeps your upper airway open at night |
CPAP machine | Using a continuous positive airway pressure (CPAP) machine at night; many people notice their symptoms stop with CPAP |
Surgical evaluation | Referral to an ear, nose and throat specialist (otolaryngology) for a surgical evaluation |
Your provider will likely offer nonsurgical treatment options first. [4] Many people find comfort in speaking with a mental health professional if their symptoms affect their mental health or social well-being. [4]
Questions to Ask Your Healthcare Provider
Do I need to participate in a sleep study?
Do you want to talk to my bed partner about what they heard while I was sleeping?
What type of treatment do you recommend?
Are there side effects of treatment?
When Should You See a Healthcare Provider?
Visit a healthcare provider if you experience nighttime groaning or someone lets you know that they heard you. Always talk to a provider if you are not getting the quality or amount of sleep you need.
Outlook / Prognosis
What Is the Outlook for Catathrenia?
There are no known long-term health consequences of catathrenia. [4] Though it may sound alarming to your friends or family who hear you at night, this condition can have a significant impact on your mental health. [4]
Treatment options are available to reduce or eliminate nightly groaning. Many people notice their symptoms stop when they use a CPAP machine. [4]
Prevention
Can Catathrenia Be Prevented?
Because the exact cause is unknown, catathrenia cannot be reliably prevented. What you can do is protect your sleep and your well-being: mention any nighttime groaning to a provider early, seek treatment if the groaning disrupts your rest or relationships, and consider talking with a mental health professional if the condition affects your self-esteem or social life. Early treatment can reduce or eliminate nightly groaning before it takes a toll on your mental health.
Conclusion
Catathrenia is one of those sleep disorders that sounds far more alarming than it actually is. Nightly groaning from your own voice box can rattle a bed partner and leave you waking with a dry mouth, a sore throat, and a headache, but it does not threaten your physical health. The real costs are to sleep quality, confidence, and social life, which is exactly why it deserves attention. A provider can record the sounds, rule out sleep talking and snoring, and run an overnight sleep study if needed. Nonsurgical options such as oral appliances and CPAP machines come first, and many people find their groaning stops completely.
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Frequently Asked Questions (FAQ)
What is catathrenia?
Catathrenia is a sleep-related breathing disorder that causes moaning or groaning during sleep. The noise happens as you exhale, is loud, and lasts for a couple of seconds or up to 40 seconds. [4]
What does catathrenia mean?
Catathrenia is a term of Greek origin used for groaning during sleep. It is also called nocturnal groaning. [4]
Is catathrenia common?
No. Two studies found it affects 0.17% of people in Japan (25 of 15,052 people over 10 years) and 0.4% in Norway (4 of 1,004 people in one year). It may be underreported because it is often mistaken for snoring. [4]
Do people with catathrenia hear themselves groaning?
Most often, no. You usually will not notice or hear yourself as it happens. A sleeping partner or household member is usually the first to tell you. [4]
Does catathrenia happen every night?
This symptom typically occurs nightly, during both REM and non-REM sleep. [4]
How long does each groaning episode last?
Each episode lasts for a couple of seconds or up to 40 seconds. [4]
Can catathrenia wake you up?
Yes. Nocturnal groaning may wake you up, and in the morning you may feel like you did not get a full night's rest. [4]
What does catathrenia sound like?
The moaning or groaning can sound loud, monotone, sexual, gloomy, humming, cracking, or end with a grunt or sigh. [4]
Does the groaning happen on inhale or exhale?
It happens when you exhale and stops when you inhale. [4]
What other sleep complaints do people with catathrenia report?
While many people have no sleep-related complaints, some report snoring, mouth breathing, and sleep interruptions. [4]
Why do I wake up with a dry mouth and sore throat?
Morning symptoms such as dry mouth, sore throat, hoarse voice, headache, fatigue, grogginess, and difficulty concentrating happen because of mouth-only breathing during sleep, and they also reflect reduced sleep quality. [4]
What causes catathrenia?
The exact cause is unknown. Research suggests malfunctioning neurons (nerve cells) in the brain at the respiratory center (the medulla oblongata) cause prolonged exhaling, and vocal cord vibration during exhaling creates the groaning sound. [4]
What is the medulla oblongata?
The medulla oblongata is the brain's respiratory center, and it is where researchers suspect malfunctioning neurons cause the prolonged exhaling behind catathrenia. [4]
Can anxiety cause catathrenia?
It is not clear if anxiety causes catathrenia. Studies are still ongoing to learn more and to determine if conditions like stress can trigger symptoms. [4]
Is catathrenia hereditary?
Current research suggests you are more at risk of nocturnal groaning if someone in your biological family also has this condition. [4]
Is catathrenia dangerous?
No. Catathrenia is not dangerous to your physical health, but it can affect sleep quality and interpersonal relationships. [4]
How does catathrenia affect mental health?
It can cause stress or social embarrassment. [4] It can be frustrating not to control the noises your body makes while sleeping, and some people avoid overnight stays with others to prevent being heard.
How is catathrenia different from snoring?
Snoring happens as you inhale, while catathrenia happens as you exhale. [4] Catathrenia groaning comes from the larynx (voice box), while the snoring sound comes from the pharynx (throat).
Can catathrenia be mistaken for sleep talking?
Yes, which is why a provider may ask you to record yourself sleeping so they can play back the audio and rule out sleep talking or snoring. [4]
How is catathrenia diagnosed?
A provider diagnoses it after a clinic visit that includes a medical history about your signs and symptoms, a physical exam, and possibly further testing such as a sleep study. [4]
What questions will my provider ask?
Your provider will ask how you feel when you wake up and what other people have heard or observed while you are sleeping. [4]
What is a sleep specialist?
A sleep specialist (somnologist) is a doctor who specializes in sleep disorders. Your primary care physician may refer you to one. [4]
What is a sleep study (polysomnogram)?
A sleep study is an overnight test at a sleep center that monitors your brain activity, breathing, and how other body systems work as you sleep. [4]
Why should I record myself sleeping?
A recording lets your provider play back the audio and listen, which helps rule out other conditions like sleep talking or snoring. [4]
Does catathrenia always require treatment?
No. Catathrenia does not always require treatment [4], but options are available if the groaning disrupts your sleep or relationships.
What are oral appliances for catathrenia?
An oral appliance (like a retainer) keeps your upper airway open at night. [4]
What is a CPAP machine?
CPAP stands for continuous positive airway pressure. [4] It is a machine used at night that delivers gentle air pressure to keep the airway open.
Does CPAP stop catathrenia groaning?
Many people notice their symptoms stop when they use a CPAP machine. [4]
When is surgery considered for catathrenia?
A provider may refer you to an ear, nose and throat specialist (otolaryngology) for a surgical evaluation [4], usually after nonsurgical options.
What treatment does a provider try first?
Providers will likely offer nonsurgical treatment options first [4], such as oral appliances or CPAP.
Can mental health support help with catathrenia?
Yes. Many people find comfort in speaking with a mental health professional if their symptoms affect their mental health, self-esteem, or social well-being. [4]
Are there long-term health consequences of catathrenia?
There are no known long-term health consequences of catathrenia. [4]
What questions should I ask my provider?
Ask whether you need a sleep study, whether your bed partner should describe what they heard, what type of treatment is recommended, and what side effects treatment may have. [4]
When should I see a healthcare provider?
Visit a provider if you experience nighttime groaning or someone tells you they heard you. Always talk to a provider if you are not getting the quality or amount of sleep you need. [4]
Can catathrenia be prevented?
Because the cause is unknown, it cannot be reliably prevented, but early evaluation and treatment can reduce or eliminate nightly groaning and protect your sleep quality and mental health.
Related Reading
References
Martel Q, Maranci JB, Philippe C, et al. Lamentations in the night: A systematic review on catathrenia. Sleep Med Rev. 2024;75:101944. PMID: 38718707. https://doi.org/10.1016/j.smrv.2024.101944
Yu M, Hao Z, Xu L, et al. Differences in polysomnographic and craniofacial characteristics of catathrenia phenotypes: a cluster analysis. Nat Sci Sleep. 2024;16:625-638. PMID: 38831958. https://doi.org/10.2147/NSS.S455705
Alonso J, Camacho M, Chhetri DK, et al. Catathrenia (nocturnal groaning): a social media survey and state-of-the-art review. J Clin Sleep Med. 2017;13(4):613-622. PMID: 28095968. https://doi.org/10.5664/jcsm.6556
Cleveland Clinic. Catathrenia (Nocturnal Groaning). Cleveland Clinic Health Library. Last updated August 28, 2024. https://my.clevelandclinic.org/health/diseases/catathrenia
American Academy of Sleep Medicine. What is groaning? Sleep Education. Last reviewed December 2020. https://sleepeducation.org/sleep-disorders/groaning/
Sleep Foundation. Catathrenia: Why Do I Moan in My Sleep? Sleep Foundation. Updated May 29, 2026. https://www.sleepfoundation.org/sleep-related-breathing-disorders/catathrenia
Medical disclaimer
This article is for general informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider for diagnosis and treatment decisions related to your individual health situation.
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