THE concept of healthy sleep has won increasing attention in China in recent years due to improvements in medical techniques and in the public's awareness of health issues.

　　Besides insomnia and disturbed sleep, snoring is a common phenomenon. It is, in fact, a sign of unhealthy sleep, even though many people think loud snoring means good and deep sleep.

　　According to a random sample survey of 6,826 individuals aged over 30 years conducted by the Sleep Respiratory Disorder Studysgroupsat Ruijin Hospital, about 57.1 per cent snore during sleep, with 23.7 per cent snoring to a moderate or severe degree. The incidence of snoring increases with age and is more common among men than women.

　　Medical research shows that snoring and insomnia are related phenomena: about 37 per cent of individuals who snore moderately or severely are also insomnia patients.

　　However, few people have paid much attention to the problem of snoring. Over 36 per cent of the individuals surveyed by Ruijin Hospital didn't regard snoring as a sleeping disorder; about 29 per cent believed that the disorder did not merit medical treatment. Only 34 per cent accepted the idea that the disorder should and could be treated.

　　Loud snoring is not only a terrible nighttime disturbance for roommates, it can also be a potentially harmful disease for snorers themselves. This is because snoring is an early symptom of sleep apnea/hypopnea syndrome (SAHS), a chronic respiratory disorder.

　　In China, about 36 individuals among every 1,000 are estimated to suffer from SAHS, but most people have a poor awareness of this disease.

　　Stop breathing

　　The shocking fact is that SAHS patients stop breathing many times during sleep although patients themselves are not aware of that.

　　The repeated breathing lags result in insufficient gas exchange in the blood which means less oxygen in the blood and excessive amounts of carbon dioxide. This can damage the brain, lungs, heart and other internal organs which are harmed by prolonged oxygen deficiency.

　　The disease also threatens people's life in the long term, contributing to serious diseases including high blood pressure, heart disease, cardiovascular diseases and impotence.

　　Though the symptoms above are not easily detected by patients themselves, they usually notice a dry mouth after sleep, headaches or feelings of extreme sleepiness during the day.

　　One woman patient, 59, could fall in sleep after standing still for just a few seconds in the metro. Although she tried to keep herself awake, she still found on numerous occasions she had fallen asleep at her lab desk.

　　In such cases, the disease can be very dangerous for machine operators and drivers. Statistics show traffic accidents among SAHS patients are from 2 to 13 times higher than among normal drivers.

　　Anyone of any age can develop a sleep disorder, but surgery or a continuous positive airway pressure device (like an oxygen mask) can ease the symptoms.

　　(Li Qingyun is a doctor in the Respiratory Department of Ruijin Hospital)