If you emit strange sounds, such as groaning or moaning, while you sleep, you may be experiencing nocturnal groaning. This condition is medically known as Catathrenia, classified as a sleep-related breathing disorder or a type of parasomnia. While the sound can be loud and alarming to anyone nearby, Catathrenia is generally considered benign and poses no immediate physical threat to the sleeper. The sounds are often not noticed by the person making them, and the most common reason for seeking treatment is a concerned bed partner.
The Specific Cause of Nocturnal Groaning
The distinct sound of Catathrenia is generated during a prolonged exhalation, which is the opposite of how snoring sounds are typically produced. Episodes often begin with a deep, silent inhalation followed by the breath being held against a closed airway, similar to a Valsalva maneuver. The resulting sound is a low-pitched, monotone moan or groan that can last anywhere from a few seconds up to nearly 50 seconds.
This vocalization originates in the larynx, or voice box, involving the active narrowing and vibration of the vocal cords as air is slowly forced out. Catathrenia episodes occur most frequently during Rapid Eye Movement (REM) sleep. While the precise underlying cause is not fully understood, research suggests it may be linked to the respiratory control center in the brain, which triggers this pattern of prolonged breathing.
How Catathrenia Differs From Snoring and Sleep Apnea
Catathrenia must be distinguished from other common, potentially more concerning, sleep issues like snoring and Obstructive Sleep Apnea (OSA). The most significant difference is the timing of the noise: Catathrenia sounds occur exclusively on the exhale, while snoring is primarily made during inhalation. Snoring is caused by the vibration of soft tissues in the back of the throat, whereas Catathrenia is a laryngeal sound produced by the vocal cords.
Unlike the loud, irregular sounds of snoring, Catathrenia is typically described as a monotone, almost humming vocalization. Catathrenia is not associated with breathing pauses, gasping, or significant drops in blood oxygen levels, which are the hallmarks of OSA. OSA involves a blocked airway and severe health risks, but Catathrenia does not involve airway obstruction. The person experiencing nocturnal groaning usually maintains normal breathing and oxygen saturation.
Addressing Catathrenia and When to Consult a Specialist
Since Catathrenia is not associated with health risks, treatment is generally only pursued when the noise severely impacts a bed partner or disrupts the sleeper’s own rest. Management strategies often begin with simple changes to mitigate the noise for others, such as a bed partner wearing earplugs or using a white noise machine. Some individuals may find relief through lifestyle adjustments that reduce stress or alcohol consumption.
A consultation with a sleep specialist is warranted if the groaning is accompanied by symptoms such as excessive daytime sleepiness, morning headaches, or unrefreshing sleep. These signs may indicate a co-existing sleep disorder like OSA. The specialist can perform a sleep study, or polysomnogram, to accurately diagnose Catathrenia and rule out other conditions. In severe cases where the groaning significantly affects quality of life, a Continuous Positive Airway Pressure (CPAP) device may be recommended, as it can often eliminate the symptom.