A GLOBAL Internet study has found that Chinese people have reduced the amount of time they sleep and have pushed back their bed time.

　　The survey shows one in every four Chinese do not usually go to bed until after midnight and over half (58 per cent) are up before

　　7 am in the morning, reported

　　ACNielsen, a leading provider of consumer and marketplace information.

　　A quarter of Chinese respondents go to sleep after midnight with another quarter going to sleep between 10 pm and 11 pm. The most popular time slot, between 11 pm and midnight, sees 40 per cent of Chinese off to bed. Only one in 10 head to bed before 10 pm.

　　"The phenomenon reveals an evolution in the lifestyles of people in China, who used to rise early and rest early 10 years ago," said Professor Jiang Fan, an expert on sleep problems from Shanghai Children's Medical Centre.

　　Habit is considered a major factor dictating Chinese people's sleep schedule, according to the survey.

　　Night owls

　　The number of night owls is especially big in Shanghai and still rising, according to Jiang.

　　There is evidence all around us that people are pushing back their bed times, with the increasing number of round-the-clock services available for consumers, the growing importance of round-the-clock convenience stores, and of course the world of the Internet, which never sleeps.

　　The 24/7 convenience chain-stores that provide food and drink are easy to find on many streets. Bars and other entertainment facilities remain open until 2 am in the morning.

　　"Our customers crowd in after 11 at night and we keep busy until the middle of the night when we close the door," said Zhang Hua, an employee of a bar on Hengshan Lu. "But during the day time, few customers come."

　　Paul Xu is one of the night owls who prefers to spend his time after work in bars.

　　He arrives at a bar or party late at night with his friends and stays until 2 am.

　　"I enjoy the night life in Shanghai. Although I sacrifice some sleep, I feel good being with my friends drinking and chatting in the bars," he said.

　　"Actually I don't need to sleep eight hours a day. Life is short. It is not wise to spend one third of life sleeping and dreaming."

　　Work hours are another reason given for diminished sleep. IT employees, officials working in accounting firms and investment banks, taxi drivers and teachers top the list of people with increasing sleep deprivation.

　　He Yonghua, a technical director of an IT firm, admitted he would stay up until 3 am in the morning and rise again at 8 am.

　　"I cannot sleep as long as others because of my work," said He.

　　He has at times had to work for 24 hours or more, after which he would sleep a whole day to "repay" the sleep debt, but he admitted that fatigue was still serious afterward.

　　Professor He Yanling from Shanghai Mental Health Centre said nearly three out of four professional women in China do not get eight hours of sleep every night.

　　Inadequate sleep is becoming an epidemic among this group.

　　School students are another group suffering from sleep deprivation, due to the burden of homework from teachers and parents. Research by the local education bureau found that poor performance by students in their studies and aggressive behaviour are linked to a lack of sleep.

　　Experts proposed postponing the first class in the morning to give students more sleep time.

　　Health hazard

　　"Our society is adapting to a longer waking day as people juggle their time between work and family," said Glen Murphy, managing director of ACNielsen China. "The luxury of a solid eight-hour sleep or an early night is long gone as people have gradually become accustomed to sleeping less and their body clocks have adjusted accordingly."

　　"The increasing pressure from career and life are factors causing less sleep," said Jiang Fan. "For those people, the reason for less sleep is not that they have trouble sleeping rather they have trouble getting to sleep."

　　Sleep apnoea, narcolepsy, insomnia are a few of the recognized disorders that prevent people from getting enough sleep.

　　"The city's insomnia is getting worse and worse as sleeping pills sales sky-rocket in Shanghai," said Jiang.

　　"Sleep deprivation can be dangerous," said Jin Xingmin, a sleep expert from Shanghai Second Medical University.

　　Professor He Yanling from Shanghai Mental Health Centre has undertaken research into the problem.

　　"A lack of sleep may lead to depression and napping during the day," said He.

　　Americans have been sleeping for fewer hours in recent years and they have also been more likely to become obese. Could there possibly be a connection?

　　Yes, say researchers at the University of Chicago.

　　They studied a group of healthy young men given a regime of only four hours sleep for a couple of nights. Hormone measurements showed a decrease in leptin, which controls appetite, and an increase in ghrelin, which increases hunger. Accordingly, the volunteers recorded an increase in desire for fatty, sweet and salty foods after their sleep deprivation.

　　The link between sleep deprivation and overeating has also been noted in animal studies.

　　"But people who suffer from inadequate sleep are not aware of the passive impact it has," said Professor Jin.

　　According to Chinese medical experts, many professional women who suffer from inadequate sleep do not realize the adverse effects this might have on their health. Only 4 per cent would see a doctor to seek help.

　　"It all depends on how much time for sleep different people require. The problems is that we cannot live without sleeping," said He.