Sleeping less or more than seven to eight hours a night heightens the risk of death, a study suggested.

The study, conducted by a medical research team at Seoul National University, followed the sleeping patterns of 13,164 Koreans for 17 years since 1993 to determine the suitable amount of sleep.

Those who sleep less than five hours have a 21 percent of higher risk of death, while sleeping more than 10 hours can increase death risks by 36 percent, according to the research.

“We found out that sleeping more than recommended hours also can lead to higher mortality rate,” professor Yoo Geun-young, who led the study, was quoted as saying. He added that the amount of sleep is a crucial indicator to further studying the mortality rate.

The research was posted on the latest edition of Journal of Preventive Medicine and Public Health.

By Ock Hyun-ju, Intern reporter
(laeticia.ock@heraldcorp.com)