Seoul, May 2 : Six out of every 10 South Korean school children spend more hours studying than recommended, a survey by a children's welfare foundation showed on Thursday.

ChildFund Korea released the result after surveying 10,140 students from elementary freshmen to high-school sophomores in December, Yonhap news agency reported.

Of those surveyed, 65.1 per cent were spending longer hours studying than deemed appropriate, while nearly 13 per cent of the middle and high school students surveyed thought the time they normally spend studying to be "excessive."

The survey showed the average study hours outside schools reached two hours and 17 minutes for lower-year elementary schoolers and two hours and 47 minutes for higher-year elementary school students.

The corresponding figures for middle and high school students were three hours and 12 minutes and three hours and 33 minutes, respectively.

Based on relevant data, the foundation recommended study time, except for school hours, to be less than an hour for lower-year elementary schoolers and less than two hours for higher-year elementary schoolers.

Up to two-and-a-half hours of studying was recommended for middle school students, and up to three hours for high schoolers.

The survey also noted that 18.8 per cent of children slept less than recommended.

Elementary schoolers slept nine hours on average, while the corresponding averages for middle and high school students stood at seven hours and 51 minutes and six hours and 32 minutes, respectively.

More than 60 per cent of those surveyed were found to spend their free time watching videos on smartphones at home alone, rather than spending time with friends or family.

Some (over 13 per cent) also suffered from insomnia, attributable, most of all, to late-night smartphone use, noise, or other environmental reasons and unfinished tasks, according to the survey.

The foundation urged the government to provide national guidelines to guarantee sleep hours and reduce study time for children to help them achieve a balanced lifestyle.

/IANS