Trends in Timing of Sleep in the General Population of Norway: 1980 to 2000

Abstract

The aim of the current study was to examine whether the timing of sleep have changed over the last two decades. As part of a general survey of activities throughout the 24-hr. cycle, collected in 1980, 1990, and 2000 by Statistics Norway, information on sleep timing was obtained for every 15-min. interval for 1 wk. All three samples were representative of Norwegians. The age span was from 16 to 74 years. Timing of sleep was significantly delayed in 2000 compared to 1990 and especially so in 1980, but with no change in total amount of sleep. From 1980 to 2000, there was an increasing discrepancy in sleep or wake timing between weekdays and weekends. The current analyses show that people sleep as much as before but do so at different times. The increased discrepancy between weekdays and weekends indicates that overall sleep habits are poorer now than previously.