Starting later can help night owls get more sleep and do their best

If you’ve always felt sharper at night and groggy in the morning, your body clock may simply run late. You’re not lazy. A new study shows that when night owls started their day later, they got more sleep and did as well on exams as natural early risers.

The researchers worked with first-year medical students whose body clocks sat far from their school schedules. Those who started class at 10:00 a.m. slept longer, had steadier daily rhythms and matched the early birds on test scores. Fitting the day to your clock works.

How the study worked

The team gave 220 incoming first-year medical students a questionnaire about their natural sleep timing. The 71 with a big gap between their body clock and their school schedule, known as social jetlag, were randomly placed into one of two groups. Thirty had classes starting at 10:00 a.m. or later, and 41 kept the standard 8:00 a.m. start. Wrist devices tracked sleep, activity and light, and body temperature rhythms showed each student’s inner clock. The results were published Oct. 29, 2026, in Chronobiology International, and since the work took place at one medical school, it speaks most directly to students like these.

What they found

On the early schedule, students with a late inner clock scored lower on exams than students with an early inner clock. Across all students, the later the inner clock, the lower the exam score, and that link showed up most clearly among those starting at 8:00 a.m.

Then came the good part. Night owls on the later schedule scored about the same as the early birds. They also slept longer, and their daily rhythms were steadier. Their rest and activity pattern held more regular from day to day, and so did their exposure to blue light, the kind that comes from screens and daylight.

In plain words, the lower scores were not about effort or brains. They were about timing. When the schedule matched the body clock, the gap went away.

What is social jetlag?

Social jetlag is the gap between the time your body wants to sleep and the time your job, school or family life asks you to be up. It feels like jetlag, but you never left home. Night owls often have the biggest gap, because most schedules start early.

What you can do today

Find out when your body naturally wants to sleep and wake. For the next three days, write down what time you first feel sleepy at night and when you wake up without an alarm. If you have any say over your schedule, such as a later meeting, a later workout or a later start for a teen at home, use what you learn to move things closer to your clock.