Catathrenia is a rapid eye movement sleep parasomnia consisting of end-inspiratory apnea (breath holding) and expiratory groaning during sleep. Catathrenia is distinct from both somniloquy and obstructive sleep apnea. The sound is produced during exhalation as opposed to snoring which occurs during inhalation. It is usually not noticed by the person producing the sound but can be extremely disturbing to sleep partners. Bed partners generally report hearing the person take a deep breath, hold it, then slowly exhale; often with a high-pitched squeak or groaning sound.
Catathrenia typically, sometimes even exclusively, occurs during REM sleep, although it may also occur to a lesser degree during NREM sleep. Catathrenia begins with a deep inspiration. The sufferer holds her or his breath against a closed glottis, similar to the Valsalva maneuver. After a period of time and some blood oxygen desaturation, there is an arousal, followed by expiration. Expiration can be slow and accompanied by sound caused by vibration of the vocal cords or a simple rapid exhalation with no sound.
There is debate about whether the cause is physical or neurological, a question that requires further study. While some speculate about a direct correlation to high anxiety and stress or the concept that catathrenia is purely psychological, there is only anecdotal evidence of either proposed cause.
Catathrenia has been defined as a parasomnia in the International Classification of Sleep Disorders Diagnostic and Coding Manual (ICSD-2), but there is debate about its classification.
There are a few other similaritiesamongst catathrenia sufferers that have not yet been studied properly:
Because catathrenia itself is not considered life-threatening, there has been very little research done in the medical community, and many experts assume that the way to treat catathrenia is to treat the underlying sleep apnea, though there is no conclusive evidence published that catathrenia results from sleep apnea, and sleep studies show that not all sufferers of catathrenia have been diagnosed with sleep apnea.
While doctors tend to dismiss it as an inconvenience, sufferers routinely describe the condition's highly negative effects on their daily lives including tiredness, low energy, dizziness and vertigo, work problems, relationship and social issues, and other physical and mental problems that could be associated with low sleep quality.
Possible remedies
Sleeping in a more upright position seems to lessen catathrenia (as well as sleep apnea). Performing regular aerobic exercise, where steady breathing is necessary (running, cycling etc.) may lessen catathrenia. Strength exercise, on the other hand, may worsen catathrenia because of the tendency to hold one's breath while exercising. Yoga and/or meditation focused on steady and regular breathing may lessen catathrenia.