For many, sleep is a quiet, restorative process, but some individuals experience sleep humming, a curious nocturnal sound. It involves vocalizations during sleep, ranging from soft, continuous sounds to louder groans. While the person humming is typically unaware of these sounds, a bed partner or family member often notices them, leading to questions about their origin.
Understanding Sleep Humming
Sleep humming, also known as nocturnal groaning or catathrenia, is a distinct sleep vocalization. It manifests as a low, continuous, monotonous hum or moan. These sounds primarily occur during exhalation, distinguishing it from snoring, which typically happens during inhalation due to airway vibrations. Unlike sleep talking, which involves coherent or incoherent speech, sleep humming is wordless. While it can occur in any sleep stage, it is often observed during rapid eye movement (REM) sleep, and may also appear in non-REM sleep stages, particularly stages 1 and 2.
Why It Happens
The exact reasons for sleep humming are not fully understood, but several factors contribute to its occurrence. One physiological explanation involves partial airway resistance or obstruction, which can cause vocal cords to vibrate during exhalation. This is a characteristic feature of catathrenia, a sleep-related breathing disorder producing sounds specifically during exhalation. Some theories suggest that malfunctioning neurons in the brain’s respiratory center might lead to prolonged exhalation, resulting in these vocalizations.
Sleep humming can also manifest as the brain and body transition between sleep stages. As individuals move through sleep cycle phases, involuntary vocalizations can occur. While catathrenia itself is not directly linked to psychological stress, broader sleep vocalizations can be influenced by psychological factors. Daily stress, anxiety, or processing emotions from the day might contribute to these nocturnal sounds.
Certain medications can alter sleep architecture, potentially leading to vocalizations. Antidepressants and sedatives, for instance, can influence sleep patterns and result in such sounds. Sleep humming might also be associated with underlying conditions, such as sleep apnea or other sleep-related breathing disorders. These conditions are less common primary causes for isolated humming, which often presents without the more severe symptoms of those disorders.
When to Consult a Professional
While sleep humming is often harmless, certain indicators suggest consulting a healthcare professional. If the humming is accompanied by other concerning symptoms, such as gasping, choking sounds, or noticeable pauses in breathing, a medical evaluation is advised. Excessive daytime sleepiness, morning headaches, or difficulty concentrating can also be signs that the humming is related to a more significant sleep issue.
Professional advice is also recommended if sleep humming significantly disrupts the sleep quality of the individual or their bed partner. A sudden onset or noticeable change in the humming’s pattern, intensity, or frequency warrants attention. Individuals with pre-existing health conditions, such as heart disease or obesity, should also consider a medical consultation, as these factors increase the risk of sleep-disordered breathing. If there is any concern regarding nocturnal vocalizations, discussing the matter with a doctor or sleep specialist can provide peace of mind and appropriate guidance.