Kiwis are among the earliest sleepers and risers in the world, according to new research on sleeping patterns. A University of Michigan study using data from Entrain, a smartphone app aimed at reducing jetlag, found Kiwis on average go to sleep at 10.48pm and wake at 6.54am - an average of 8 hours and 6 minutes sleep. Kiwis' sleep time was the second earliest average sleep time of the 100 countries involved in the study. Australians were the first, with an average sleep time of 10.45pm. Kiwis were the fifth earliest to rise, behind Americans, Australians, the Danish and Belgians. The app asked users for their normal sleep times, home time zone and typical lighting. It also recorded hourly light, sleep schedules and subjective experiences of jetlag. There were 5400 participants in the study. The good news for Kiwis: the study authors Olivia Walch, Amy Cochran and Daniel Forger concluded there was a direct correlation between an early bedtime and a quality night's sleep. The news wasn't so good for Spaniards who were the last to to go to sleep with an average sleep time of 11.45pm. Meanwhile, United Arab Emirates citizens enjoyed the longest sleep-in, waking up at 7.45am on average. The Dutch reported the most amount of sleep of any nation, averaging 8 hours and 12 minutes, while sleep-deprived people from Singapore and Japan managed just seven hours and 24 minutes. Societal factors such as social pressures were found to govern bedtime, while the body's internal clock governed wake time. The body has an internal clock, known as a circadian rhythm, which works on a 24-hour schedule and synchronises with daily signals from the environment, mainly light and darkness. People slept less and woke earlier until they reached 50 to 60 years when the trend reversed. The study also found women slept about 30 minutes more than men across nearly every age group by both going to bed earlier and waking up later. University of Auckland Professor of statistics Thomas Lumley warned that data were probably not representative of all New Zealanders. "It's people who use a smartphone app to reduce jetlag, so it's probably not representative of a large portion of the population." He also said New Zealanders represented less than two per cent of participants in the study - likely less than 100 people.
• The study used sleeping data from 5400 respondents across 100 countries. People regularly waking up before 3am or after 11am were excluded from the research, as were people who reported regular sleep durations of shorter than four hours or more than 11 hours. • The nationalities most represented in the study were: United Kingdom, USA, Australia, New Zealand, Belgium, United Arab Emirates, Germany, Canada, France, Japan, Singapore, Spain, Brazil, Denmark, Switzerland, China, Hong Kong, Italy and Mexico.