Later College Class Start Times Reduce Grade Inequity in Minority Groups

Historically marginalized college students, such as black and Hispanic students, are often receiving lower grades than their white classmates. While many factors play into this disparity, one such factor that has yet to be considered is the time of day at which classes are offered. It is known that there is a biological delay sleep-wake cycles in students that are around college age, leading to a natural later bed time, than older individuals. Indeed, it has been shown that classes that start later in the day positively impacts student performance. However, it has yet to be determined how class start time impacts college students in a sex, race/ethnicity and age specific manner. We hypothesized that young, male black and Hispanic students would benefit more from starting class later in the day. To determine this, we analyzed over 1 million grade and class start time entries from Michigan State University, examining the start times of classes and the resulting student grades. We confirmed that starting classes after 10 am correlates with a higher GPA, and that male students on average have lower GPAs than female students. We also found that male and female black and Hispanic students have lower GPA as compared to white of the same sex students, though this difference in GPA is smaller later in the day. These data highlight that later start times for college classes can reduce inequity in grades between students. BVL was supported by T32HD087166 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.