Study Finds Short Naps Do Not Relieve Sleep Deprivation

A recent study from Michigan State University’s (MSU) Sleep and Learning Lab found that a nap during the day will not restore a sleepless night.

“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 study author Kimberly Fenn, director of MSU’s Sleep and Learning Lab, in a press release. “We found that short naps of 30 or 60 minutes did not show any measurable effects.”

This study was among the first to measure the effectiveness of shorter naps, according to the study authors.

“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 in the press release.

The deepest and most restorative stage of sleep is known as slow-wave sleep (SWS), which is marked by high amplitude, low frequency brain waves, and is the sleep stage when the body is most relaxed.

“SWS is the most important stage of sleep,” Fenn said in a press release. “When someone goes without sleep for a period of time, even just during the day, they build up a need for sleep; in particular, they build up a need for SWS. When individuals go to sleep each night, they will soon enter into SWS and spend a substantial amount of time in this stage.”

Fenn and her research team recruited 275 college-aged participants for the study who completed cognitive tasks when arriving at MSU’s Sleep and Learning Lab in the evening. They were then randomly assigned into 3 groups: the first group being sent home to sleep, the second staying in the lab overnight and having the option to take either a 30- or 60-minute nap, and the third did not nap at all in the deprivation condition.

The next morning, participants resumed in the lab to repeat the cognitive tasks, which measured attention and placekeeping, or the ability to complete a series of steps in a specific order without skipping or repeating them even after interruption.

“The group that stayed overnight and took short naps still suffered from the effects of sleep deprivation and made significantly more errors on the tasks than their counterparts who went home and obtained a full night of sleep,” Fenn said in a press release. “However, every 10-minute increase in SWS reduced errors after interruptions by about 4%.”

According to Fenn, these numbers are significant when considering the types of errors that are likely to occur in sleep-deprived operators, such as surgeons or police officers, and the 4% decrease in errors could potentially save lives.

“Individuals who obtained more SWS tended to show reduced errors on both tasks. However, they still showed worse performance than the participants who slept,” Fenn said in a press release.

Fenn and her team hope these findings highlight the importance of prioritizing sleep and that naps cannot replace a full night of sleep.

REFERENCE

Scrap the nap: study shows short naps do not relieve sleep deprivation. MSU Today. August 12, 2021. Accessed August 17, 2021. https://msutoday.msu.edu/news/2021/napping-effectiveness