BEIJING - Nearly 60 percent of young Chinese interviewed in a recent survey by China Youth Daily said they habitually go to bed late and don't fall asleep until after 11 pm.

The survey was conducted to mark the 21st World Sleep Day, which falls on Sunday.

Of the 2,002 survey respondents aged between 18 and 35, only 8.5 percent said their average sleeping time exceeds eight hours, and over four-fifths usually sleep between six and eight hours a night.

Hu Bo, a 29-year-old man who works in a private company in Beijing, rarely goes to sleep before midnight. "I come home from work every day after 8 p.m., sometimes with an empty stomach. I use my computer or mobile phone for a while after getting everything done before bed, and by then it's already late," he said.

Despite going to bed late, Hu said it usually takes him over half an hour to fall asleep. Like him, over 11 percent of the respondents are unable to drop off to sleep within 30 minutes after going to bed.

When asked about their sleep quality, less than half of young Chinese said they sleep well. Excessive dreaming (46 percent), light sleeping (45.4 percent) and early awakening (33.1 percent) are the most common sleep problems among young Chinese.

Poor sleep quality is harmful to both physical and mental health, weakening the immune system or causing emotional irritability, said Zhang Xiaowei, a health expert with the Hebei General Hospital.

To improve their sleep quality, 55.4 percent of the respondents said they would improve their bedtime habits, 41.7 percent said they would listen to soothing music before going to bed and 35.8 percent said they would increase their amount of exercise during the daytime.