Catathrenia is a disorder that causes vocal groaning during sleep and can last for an extended amount of time, occurring on a nightly basis.
The groaning can be quite loud and your breathing slows when it occurs. Taking a deep, slow breath, you make a long moaning, humming or cracking sound while exhaling. The duration can range from a few moments to over forty seconds, usually ending with a sigh or grunt. Clusters of groaning may recur many times during the night, lasting two minutes up to an hour.
Facial expressions remain relaxed and don't indicate any distress. Despite the moans, it does not seem to be indicative of any emotion. It can accompany lying in any posture; yet usually stops when you move around in bed. Nonetheless, it may recommence later on during your slumber.
If you moan without being conscious of it, this may be more disturbing to those around you such as your bed partner, roommate or family.
Other descriptions of the groaning sound include the following:
- High-pitched or cracking sounds
- Loud humming
- Loud roaring
The cause of sleep-related groaning remains a mystery, and there is no evidence indicating it is connected to any issues in breathing, abnormal brain activity, medical conditions revealed through physical exams, or mental disorders.
It is possible to experience mild symptoms related to sleeping, such as restlessness and daytime lethargy due to groaning. In most cases, there are no major sleep issues. The morning could also present with hoarseness of the voice and a sore throat.
There are four stages of sleep which make up one sleep cycle. Each cycle generally takes around 90-120 minutes and you usually experience four to six per night. REM (Rapid Eye Movement) sleep is the fourth period and is normally around 20-25% of your total sleep time, varying with age. It's during this stage that groaning often occurs.
The initial REM stage typically lasts a few minutes. Each sleep cycle sees it become increasingly extended, with the ultimate episode potentially reaching up to an hour in length. Groaning typically happens during this final REM period but may feature from time to time during alternate phases of sleep too.
A moaning sound can also be experienced during an epileptic seizure, making it distinct from the groaning that occurs on a regular basis. Snoring also produces a moaning type of sound when one inhales, in contrast to groaning which takes place on exhalation. Furthermore, people may make a harsh, shrill, creaking sound known as stridor while breathing, primarily when they sleep. However, this is not intermittent like groaning; rather stridor happens with almost every breath taken.