Extra 19 minutes of sleep linked to better college grades in field experiment

Researchers at the University of Pittsburgh and collaborating institutions conducted a field experiment published in the Journal of Political Economy to test whether increasing sleep duration causally improves academic performance. The study enrolled 1,149 college students across several waves, all of whom received Fitbit devices to track sleep objectively.

At baseline, participants averaged 6.6 hours of sleep per night and slept less than six hours on nearly 29 percent of weeknights. Students were randomly assigned to a treatment group that received personalized bedtime reminders and a financial incentive of $4.75 per night for four weeks if they reached at least seven hours of sleep, or to a control group that wore the devices but received no prompts or rewards.

During the intervention period, the treatment group increased the share of nights meeting the seven-hour target by 26 percent and raised average nightly sleep by 19 minutes. After the reminders and payments ended, a smaller gain of about eight minutes per night persisted relative to baseline.

Using official university transcripts, the researchers found that students in the treatment group improved their average course performance by 0.075 to 0.089 grade points during the intervention semester. A similar improvement appeared in the following semester, indicating the academic benefit outlasted the active intervention.

The authors describe the grade improvements as modest and emphasize that replication is needed. They note that prior research had largely shown correlations between sleep and grades, whereas this experiment demonstrates a causal link by manipulating sleep directly.

Health economist Osea Giuntella said the simplicity of the intervention — reminders and small incentives — makes it adaptable for other settings such as high schools and workplaces. The study was funded by the National Science Foundation and the National Institute on Aging.