Which countries get the best night’s sleep?

SLEEP IS ESSENTIAL to human health. It takes up around one-third of people’s lives. And yet surprisingly little is known about it. Understanding of how sleep varies across countries is particularly limited. It is well known, for example, that people in east Asia tend to sleep less than those in America or Europe, but not whether the quality of their sleep is better or worse. Surveys show that some countries are peopled by night owls, but others by early birds. But why this is so remains an open question.

A new paper attempts to fill some of the gaps. Using anonymised data collected from a popular wearable device between January 2021 and January 2022, researchers from the National University of Singapore and Oura Health, a Finnish sleep-tech startup, analysed the sleep habits of more than 220,000 people across 35 countries. Whereas sleep research has historically relied on survey data collected from a small number of people at a single point in time, sleep-tracker apps can track sleep objectively, from the movements, heart rates and body temperatures of large samples of users over long periods. You can see how countries stacked up in our interactive Lie-in-dex below.