Who sleeps best? Longitudinal patterns and covariates of change in sleep quantity, quality, and timing across four university years.

This study tracked change over time in sleep quantity, disturbance, and timing, and sleep's covariations with living situation, stress, social support, alcohol use, and grade point average (GPA) across four years of university in 186 Canadian students. Women slept longer as they moved through university, and men slept less; rise times were later each year. Students reported sleeping fewer hours, more sleep disturbances, and later rise times during years with higher stress. In years when students lived away from home, they reported more sleep disturbances, later bedtimes, and later rise times. Living on campus was associated with later bedtimes and rise times. Alcohol use was higher and GPA was lower when bedtimes were later. The implications of these observed patterns for understanding the correlates and consequences of university students' sleep are discussed.