too little use electronic devices such as computer tablets and mobile phones, the survey fou
nd, and youths whose parents use smartphones in front of them are more likely to have less sleep.
Other factors, such as noise and light pollution, contributed to the problem, the report said.
The survey also indicated that good sleep results in higher efficiency in study. Students who sleep longer generally fini
sh homework in two and three hours per day, while those who sleep less require four to six hours.
Gao Xuemei, vice-president of the society, said studies have shown that decreasing sle
eping time for children and teenagers has been a global trend in the past 10 years, but the problem appears to be
worse in East Asia, including China, largely due to a heavier load of school homework.