SINGAPORE - Researchers at the Duke-NUS Medical School have found that university students who have classes in the morning have worse grades than those who have fewer or no morning classes.

The study looked at the scores of 33,818 students at the National University of Singapore (NUS) across six semesters between 2016 and 2019. The students were from all faculties except medicine, which has a different grading system.

Students’ grades were lower when they had morning classes on more days of the week. The researchers defined morning classes as any class that starts before noon.

Associate Professor Joshua Gooley in the neuroscience and behavioural disorders programme at Duke-NUS Medical School, one of the co-authors of the study, said students who go from having no morning classes to having morning classes on three or more days of the week may see their grades drop from an A- to a B+, or from a B+ to a B for a course.

The Duke-NUS study also found that students with 8am classes are more likely to skip class and have less sleep than those with classes that start later.

Researchers said the lack of sleep impairs one’s attention and memory processes, which may prevent students from reaching their full learning potential in class.

Singaporeans clocked only 6.6 hours of sleep on weekdays in 2020, with a final average score of 6.8 hours daily, down from 7 hours in 2019, according to the Philips 2021 global sleep survey.

Fatigue and oversleeping are also commonly why university students skip classes, another factor for the poorer performance, according to the Duke-NUS study, published in the journal Nature Human Behaviour in February.

Researchers found the attendance for 8am classes to be about 10 per cent lower than for all other classes that started later, according to the study.

These insights were drawn using the Wi-Fi connection logs of 23,391 students to estimate students’ lecture attendance rates as well as activity data from special sensing watches, which use a motion sensor to track whether the wearer is awake or asleep, of 181 students over six weeks.

To determine if early morning classes were linked to students getting less sleep, the researchers also analysed activity data with the day and night patterns of digital learning platform logins of 39,458 students.

The study stated that even though students frequently slept past the start of 8am classes, they still lost about an hour of sleep on average compared to days with only afternoon classes or no classes.

There have been calls by MPs and experts in the past for schools to start later, but usually for primary and secondary students.

Prof Gooley said: “The take-home message from our study is that universities should reconsider mandatory early morning classes.”

He added that 10am would be a good time to start classes for most students and faculty members.

“There are some students, such as night owls, who would still lose out on sleep if classes were pushed back to 10am, but most students would be able to sleep in longer and reach class on time,” he said.

Undergraduate Aw Yuh Shi, 24, is among those who prefer afternoon classes as she is most productive at night, at times going to bed only at 6am. She has five morning classes, with the earliest starting at 9.30am.

While she attends morning classes that are graded, she skips the recorded ones as she would rather watch them online than wake up early for class.

“Whenever I force myself to attend morning classes, I find myself zoning out a lot, not being able to absorb the knowledge and think critically, especially with insufficient sleep,” the mechanical engineering student added.

However, some students favour morning classes as they end school earlier and spend the afternoon studying on their own.

Mr Jason Chan, 23, who has only one morning class, said he is not as productive in the afternoon compared to mornings.

“When I have lessons in the morning, I’m forced to go to school earlier and can spend my time in school fruitfully before going home,” said Mr Chan, who is majoring in communication studies with a minor in translation.

“Though some people prefer burning the midnight oil, I like to work in the day and find myself procrastinating when I have afternoon classes,” he said.

The researchers are also now studying the differences between class attendance, sleep, well-being and academic performance between early birds and night owls.

Correction note: This article has been edited for clarity.