An application for smartphones enabled US researchers shed light on sleep habits in the world and clarify the role played by the pressures of society and biological rhythms, according to a study released Friday.
Scientists identified as age, sex and the amount of natural light to which a human being is exposed affect sleep duration in 100 countries and determine when people go to bed and wake up.
This work, published in the journal Science Advances, helped demonstrate how the pressures of social life affect circadian rhythms, the internal clock of people, mainly when going to bed.
"It seems that society and stimuli determine especially bedtime and that the internal body clock sets the time to wake up," even if professional obligations, children and the school also play a role, said Daniel Forger a mathematician at the University of Michigan, co-author of the research.
Sleep deficit is moreover linked to the time you go to bed, he added.
These same scientists used the free application for mobile phone "Entrain" which launched in 2014 to help travelers adjust to time differences, allowing them to collect large amounts of data about the sleep habits of thousands of people in different countries.