Global sleeping patterns revealed by app data.
It showed the Dutch have nearly an hour more ∈ bed every night than people ∈Singapore or Japan.
The study, published ∈Science Advances, also found women routinely get more sleep than men, with middle-aged men getting the least of all.
The researchers say the findings could be used to deal with the "global sleep crisis".
The study found people ∈Japan and Singapore had an average of seven hours and 24 minutes sleep while the people ∈ the Netherlands had eight hours and 12 minutes.
People ∈ the UK averaged just under eight hours - a smidgen less than the French.
The later a country stays up into the night, the less sleep it gets. But what time a country wakes up seems to have little effect on sleep duration.
Prof Daniel Forger, one of the researchers, said there was a conflict between our desire to stay up late and our bodies urging us to get up ∈ the morning.
The study also showed women had about 30 minutes more per night ∈ bed than men, particularly between the ages of 30 and 60.
And that people who spend the most time ∈ natural sunlight tended to go to bed earlier.
A strong effect of age on sleep was also detected. A wide range of sleep and wake-up times was found ∈ young people but "that really narrows ∈ old age," said Prof Forger.
"It highlights that although our body clocks are programming us to do certain things, we can't as we're ruled by social circumstances.
"We won't know the long-term consequences of this for many years."
Adaptado de: http://www.bbc.com/news/health-36226874 Acessado em 7 de maio de 2016.
In the sentence: “The researchers say the findings could be used to deal with the "global sleep crisis". the modal verb could expresses:
