Singaporeans sleep the least - blame it on society
Social pressures are forcing people to cut back on their sleep, contributing to a "global sleep crisis".
The study based on research collected through smartphone app Entrain also shows people in Singapore having the lowest average amount of sleep. Entrain was launched in 2014 to help users fight jetlag.
The average amount of sleep in the world varies from a minimum of 7 hours 24 minutes in Singapore and Japan to a maximum of eight hours 12 minutes in the Netherlands, the study found.
The app enabled scientists from the University of Michigan to track sleep patterns around the world - gathering data about how age, sex and the amount of natural light to which people are exposed affect sleep patterns in 100 countries - and better understand how cultural pressures can override biological rhythms.
"The effects of society on sleep remain largely unquantified," said the study published in the journal Science Advances, AFP reported.
"We find that social pressures weaken and/or conceal biological drives in the evening, leading individuals to delay their bedtime and shorten their sleep."
Lack of sleep is mostly affected by the time people go to bed, the study, released on Friday, found.
Middle-aged men get the least amount of sleep - less than the recommended seven to eight hours. And age is the main factor determining amount of sleep.
Scientists asked some 6,000 people aged 15 and older to send anonymous data about sleep, wake-up and lighting environment. The app asked users to submit their age, sex, country and time zone.
Although a difference of 48 minutes may seem inconsequential, a lack of sleep for half an hour can have significant effects on cognitive function and health, the researchers said.
People who need sleep suffer a reduction in their cognitive abilities without really being conscious of it, according to the new study.
"Impaired sleep presents an immediate and pressing threat to human health," it says.
Chronic lack of sleep increases the risk of obesity, diabetes, hypertension and cardiovascular disease, according to the Centers For Disease Control And Prevention.
The study also found that women sleep 30 minutes longer than men on average by going to bed earlier and rising later, and that people exposed longer to natural light every day often go to bed earlier.