Almost everyone who learns about catathrenia learns about it from someone else — a partner who's been kept awake by a strange, long, groaning sound. It's a drawn-out vocal noise, almost a moan, made on the out-breath during sleep, sometimes for several seconds, often repeating. The person making it has no idea and wakes up feeling fine. It's odd, it's under-recognised, and it's usually harmless — but it's worth knowing what it is, because it's frequently mistaken for something it isn't.
What catathrenia actually is
The name means "to groan" (from the Greek), and that's exactly what it is: nocturnal groaning. During sleep the person takes a breath in, then releases it slowly through a partly-closed voice box, producing a long, monotone groan or moan. It tends to happen in clusters, often in the second half of the night, and more during REM sleep. Sleep specialists classify it as a parasomnia; unlike snoring it happens on the exhale, and unlike sleep talking it's a wordless sound. Crucially, it usually doesn't fragment the sleeper's own sleep — the main casualty is the bed partner.
Why it happens (and who gets it)
Honestly, the cause isn't fully pinned down. It's linked to the way breathing and the voice box are controlled during sleep, and it appears in otherwise healthy people, often younger adults. It's not the same as snoring and it's not a form of pain or distress, despite how mournful it can sound. Research is ongoing into airway shape and jaw position as contributors, and a mandibular advancement device has been trialled with mixed results.
It sounds like suffering and isn't. The groan is the machinery of breathing and voice overlapping in sleep — nothing more sinister.
When to see a doctor
Catathrenia is generally benign, so treatment is often unnecessary — but it's worth a professional opinion if it's straining a relationship, if there's any doubt about whether it's actually catathrenia versus snoring with breathing pauses, or if it comes with gasping, choking, witnessed pauses or daytime tiredness (which point toward sleep apnea instead). A sleep study can tell them apart cleanly.
Where SleepTrace fits
This is exactly the kind of thing a phone is good at. SleepTrace records the sounds of your night on your iPhone and lays them over your sleep stages, so instead of relying on a bleary partner's description you can actually hear the sound, and see whether it lands on the out-breath in REM (more like catathrenia) or comes bundled with inhale-snoring and pauses (worth checking for apnea). It won't diagnose, but it turns a vague "you make a weird noise" into something specific.
References
- Alonso J, Camacho M, Chhetri DK, Guilleminault C, et al. Catathrenia (nocturnal groaning): a social media survey and state-of-the-art review. J Clin Sleep Med (2017). Europe PMC
SleepTrace is a wellness app, not a medical device. This article is general information, not medical advice. If your symptoms are frequent, severe or worrying, please talk to a doctor.
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