Students Achieve Poorer Grades When Classes Don’t Sync with Biological Clocks

Might it be possible to blame your college grades on whether you are a natural night owl or an early bird? Possibly to some extent, according to the results of a two year study involving nearly 15,000 students. The study, by the University of California at Berkeley’s Benjamin Smarr, Ph.D., and Northeastern Illinois University’s Aaron Schirmer, Ph.D., found that students perform less well academically when their class times don’t sync with their natural biological clocks. This mismatch causes a phenomenon known as social jet lag (SJL) – effectively deficits in learning and attention that occur when the natural circadian rhythms of an individual are not in sync with real-world commitments such as class times at college. 

“We found that the majority of students were being jet-lagged by their class times, which correlated very strongly with decreased academic performance,” Dr. Smarr says. “Our research indicates that if a student can structure a consistent schedule in which class days resemble non-class days, they are more likely to achieve academic success,” adds professor Aaron Schirmer, an associate professor of biology at Northeastern Illinois University.

The researchers publish their findings in Scientific Reports, in a paper entitled, “3.4 million real-world learning management system logins reveal the majority of students experience social jet lag correlated with decreased performance.”

Owls performed worst of all the groups due to chronic social jet lag. [Benjamin Smarr]

The inbuilt human circadian system coordinates each person’s natural internal body clock and aligns daily (circadian) rhythms to the 24 hour day, the researchers note. This stable internal clock determines our individual ‘chronotype’. Some of us are naturally more alert and active in the mornings, while some of us perform better in the afternoon or evening and prefer to stay up later. Our circadian clock, and so ‘chronotype’, is determined largely by genes, the researchers write. There are patterns, however, prior studies have also found that men have later sleep times than women and so are more active at night, and while young adults have a later sleep-wake cycle during puberty, older people tend to be more active earlier. Circadian rhythms do also shift with seasonal changes in light.

But we can’t always choose to carry out our daily activities at times that match our chronotype. And this mismatch between an individual’s circadian phase and their environment because of social imposition, or social jet lag, has been linked with increased risks of disease. Chronotype can also feasibly also impact on education. Many school timetables, for example, are set around the 8 am to 4 pm period of the day, which is better suited to early chronotypes. Previous research has indicated that  “late chronotype students are at a greater risk for persistent SJL relative to their academic environment,” the authors note. This can impact on poorer academic performance at every level, from primary school right through to college and then medical or professional education. 

However, studying the relationship between chronotype and academic performance is tricky because creating personal profiles of sleep and circadian rhythms for individual students is costly and time consuming.  This “limits our ability to create large scale maps of how SJL manifests over real-world populations, and this in turn limits our ability to assess how educational policies aimed at improving learning outcomes are hampered by SJL,” the researchers note.  “… without the ability to make personal profiles automatically, it is impossible to generate profiles for the entire student population, which would allow for identification of at-risk students and the implementation of targeted interventions.”

As an alternative approach Dr. Smarr and Professsor Schirmer tracked the daily online activity profiles of thousands of students logging in to campus servers. They categorized each student as a “night owl,” a “daytime finch,”, or a “morning lark,” based on their online activities on their days off college, and compared a student’s chronotype with class times throughout the day and academic outcomes.  They took into account how the students had scheduled their classes during different semesters over the two year online activity monitoring period. “We hypothesized that, overall, early chronotypes would have an advantage, but that later chronotypes would have a relative advantage in later classes, when their SJL is lowest,” they note.

The results showed that 60% of students experienced an average daily SJL of more than 30 minutes. However the 40% or so of students whose biological clocks were most in sync with their class times performed better and recorded better grades. Another 50% of students had scheduled classes before they had reached full alertness, while the remaining 10% had peaked before their classes started. Interestingly, the night owls seemed to be at the greatest overall disadvantage. “… owls showed a significant academic performance deficit at all class times,” the researchers note.

“Because owls are later and classes tend to be earlier, this mismatch hits owls the hardest, but we see larks and finches taking later classes and also suffering from the mismatch,” Smarr says. “Different people really do have biologically diverse timing, so there isn't a one-time-fits-all solution for education.” However, he adds, “rather than admonish late students to go to bed earlier, in conflict with their biological rhythms, we should work to individualize education so that learning and classes are structured to take advantage of knowing what time of day a given student will be most capable of learning.”