“Night owl” students who stay up later than their early riser peers tend to fare worse academically, a new study has found.

According to the report, which was co-authored by UC Berkeley postdoctoral fellow Benjamin Smarr, college students with later sleep cycles, or “chronotypes,” are likely to score lower than their early chronotype classmates across the board, regardless of class start times.

The study examined a sample of nearly 15,000 students at Northeastern Illinois University, or NEIU, over a two-year period — making the study the largest of its kind. Smarr worked with co-author Aaron Schirmer, an associate professor of biology at NEIU, to draw from a pool of data stored in NEIU’s learning management system.

Between 2014 and 2016, Smarr and Schirmer collected time stamp data from more than 3.4 million student logins to the website. The team aggregated the data to identify patterns about student sleep cycles on a schoolwide scale, while curbing the high costs associated with administering surveys or purchasing sleep trackers.

“What we found was that the study cost a combined total of $0,” Smarr said. “We could just do it in our spare time. Even so, it was the largest study of its kind that’s ever been done.”

The experiment also found that the average college student carries 30 minutes of “social jet lag” stemming from the discrepancies between their natural wake times and their school day wake times. Smarr added that even students who naturally rise earlier in the day can experience negative academic outcomes as a result of mismatches between their class schedules and biological sleep patterns. He stressed, however, that social jet lag should not be confused with sleep deprivation.

“(Social jet lag) is not necessarily sleep deprivation but happens when you have a jet lag-like event, so you have an internal loss of synchrony,” Smarr said.

Schirmer attributed the negative academic outcomes to the culture on college campuses, where students strive to experience every aspect of college life — often at the cost of a stable sleep schedule.

“Many students feel that they can do everything and keep pushing themselves,” Schirmer said. “Students are pulling all-nighters and they think they can perform.”

Sarah Naameh, a campus freshman who said her typical bedtime ranges from 2:00 to 3:00 a.m., also pointed toward campus culture as a cause of unbalanced sleep schedules.

“I think there’s a lot of social pressure — especially here at Berkeley — to be as productive as you can be,” Naameh said. “People are talking about pulling all-nighters all the time.”

Smarr said universities could better support their students by identifying “at-risk” students in their databases and making education more personalized.

“[The] university should try to … provide an emotionally supportive environment — and Berkeley already does better than other schools with this. Thinking about biological timing needs to become a part of that conversation,” Smarr said.