Science Daily: A nap during the day won’t restore a sleepless night, says the latest study from Michigan State University’s Sleep and Learning Lab.

“We are interested in understanding cognitive deficits associated with sleep deprivation. In this study, we wanted to know if a short nap during the deprivation period would mitigate these deficits,” said Kimberly Fenn, associate professor of MSU, study author and director of MSU’s Sleep and Learning Lab. “We found that short naps of 30 or 60 minutes did not show any measurable effects.”

The study was published in the journal Sleep and is among the first to measure the effectiveness of shorter naps — which are often all people have time to fit into their busy schedules.

“While short naps didn’t show measurable effects on relieving the effects of sleep deprivation, we found that the amount of slow-wave sleep that participants obtained during the nap was related to reduced impairments associated with sleep deprivation,” Fenn said.

Slow-wave sleep, or SWS, is the deepest and most restorative stage of sleep. It is marked by high amplitude, low frequency brain waves and is the sleep stage when your body is most relaxed; your muscles are at ease, and your heart rate and respiration are at their slowest.

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