Students who take a 20-minute nap during the day can improve their cognitive functioning, according to a study conducted by researchers from Stony Brook University. The results of the study are consistent with previous sleep studies which suggest the potential benefits of catching a few z’s during the day.

The study, led by researchers from Stony Brook University, was designed to test whether or not a short, mid-day nap during normal daytime duty hours would prove beneficial for internal medicine residents by making them feel less sleepy and improving their cognitive functioning. Involved in the study were 37 first-year residents who were divided into two groups: a nap group and a rest group. To measure their attention levels during the study, researchers connected all of the residents to a device designed to monitor how often their eyes rolled, an indication for attention failures. Then, in the middle of the day, both groups took a test called the Conner’s Continuous Performance Test to evaluate their cognitive functioning and afterwards were instructed to sit in a reclining chair designed for napping. Next, residents in the nap group slept for up to 20 minutes and the study authors chatted with residents in the non-nap group to prevent them from going to sleep. Immediately afterwards, residents from both groups took the Conner’s Continuous Performance Test again. Until the end of the day, the study authors recorded the residents’ attention failures monitored by the special sleep device.

When the study authors compared the outcomes of the two groups, they found that a short, mid-day nap can improve cognitive functioning and alertness among first-year internal medicine residents. “We found that, compared with the resting-but-awake residents, the residents who actually napped experienced fewer attention failures during their work later int he day as determined by a monitor of SEMs,” the authors wrote. “Further, we found that, compared with controls who rested by stayed awake for 20 minutes, residents who had the opportunity to nap for a maximum of 20 minutes demonstrated a faster reaction time and made fewer error of omission and commission as determined by a validated test of cognitive functioning.”

The study author’s acknowledged a few limitations of their study and noted that they did not take into account two factors which may have played a role in the outcome: caffeine intake and workload. “Despite its limitations, our study demonstrates the potential benefit of a short, mid-day nap for residents and highlights the need for further research to address the effect of a mid-day nape on the quality of patient care, resident education, and longer work shifts,” the authors concluded.

The results of this study were first presented at the Sleep Health and Safety meeting of the National Sleep Foundation in March 2011 and were published in the October 2012 issue of Academic Medicine.