Attending classes and sleeping well are important for students’ academic success. Here, we tested whether early morning classes are associated with lower attendance, shorter sleep and poorer academic achievement by analysing university students’ digital traces. Wi-Fi connection logs in 23,391 students revealed that lecture attendance was about ten percentage points lower for classes at 08:00 compared with later start times. Diurnal patterns of Learning Management System logins in 39,458 students and actigraphy data in 181 students demonstrated that nocturnal sleep was an hour shorter for early classes because students woke up earlier than usual. Analyses of grades in 33,818 students showed that the number of days per week they had morning classes was negatively correlated with grade point average. These findings suggest concerning associations between early morning classes and learning outcomes.

上课和睡得好对于学生的学业成功很重要。在这里，我们通过分析大学生的数字痕迹来测试早课是否与出勤率较低、睡眠时间较短和学业成绩较差有关。 23,391 名学生的 Wi-Fi 连接日志显示，与较晚的开始时间相比，08:00 的课程出勤率大约降低了 10 个百分点。 39,458 名学生的学习管理系统登录日间模式和 181 名学生的体动记录数据表明，早课的夜间睡眠时间缩短了一个小时，因为学生比平常起得早。对 33,818 名学生成绩的分析表明，他们每周上早课的天数与平均绩点呈负相关。这些发现表明清晨课程与学习成果之间存在关联。