When teens get extra sleep on school nights, they might cut back mostly on sedentary activities like screen time without making major changes to their exercise habits, a small experiment suggests, reports the Deccan Chronicle.

Researchers asked 18 adolescents who regularly got 5 to 7 hours of rest a night to go to bed early and get an extra 1.5 hours of sleep on school nights for two weeks and wear activity trackers during the day. During a separate two-week period, researchers tracked the teens’ activity levels when they stuck to their habitual bedtimes and got their regular amount of sleep.

When they had to get extra rest, teens averaged 71 more minutes of sleep on school nights than they did before they started the experiment.

With this extra sleep, teens spent an average of 52 fewer minutes of the day being sedentary than they did when they were asked to follow their usual sleep schedules. But the amount of time they devoted to light or vigorous physical activity didn’t change much based on how much rest they got, according to the results in Sleep Medicine.