And you thought your hubby snores a lot as you change positions to catch some sleep. He may actually be a nocturnal groaner.
Called catathrenia, groaning at night is a relatively new diagnosis. The noise is produced when the sleeper is exhaling, which separates it from the sound of snoring that usually comes during inhaling.
It usually occurs in the latter part of sleep, with each groan lasting up to 50 seconds.
The groans may be very loud and can occur hundreds of times a night, researchers said.
Moreover, groaners may also experience embarrassment and anxiety because the noises they produce can sound sexual.
It is three times more common in men than woman.
"It often starts around the age 19. It may run in families, and can occur with other sleep problems, such as sleepwalking," said researchers from the British Snoring and Sleep Apnea Association.
Another research at Stanford University has also found that in 14.8 percent of cases, there is a family history of groaning.
People suffering from groaning experience next day fatigue and chronic sore throats.
Depression and anxiety may also be more common in people living with the condition, the study added.
According to researchers, polysomnography - monitoring brain waves, the oxygen level in the blood, heart rate and breathing, as well as eye and leg movements during sleep - can detect groaning and its further treatment.