Operators such as YeloSpa and Spa Eastman which offer short sleep sessions to weary customers (see below) could be helping them to maintain their memories and enhance their capability to learn as well as recharge their batteries, according to a new, albeit small, study.

A group of researchers at Saarland University in Germany have discovered that a snooze lasting 45-60 minutes leads to a five-fold improvement in how the brain retrieves information.

Memory test
The study involved a memory recall exam of 41 university students. The volunteers were asked to learn 90 single words and 120 word pairs and were tested on what they could remember immediately afterwards. The word pairs were essentially meaningless, using random duos such as ‘milk-taxi’, so that participants would not have heard them before and would not recall them due to familiarity.

After the initial memory test, one half of the participants was allowed a brief nap, sleeping for an average of 64 minutes. The other half (the control group), sat down to watch a DVD. All of the participants were then retested to see how many of the words they could recall again.

The results, published in the Neurobiology of Learning and Memory* journal, showed that while there was no memory improvement in those who slept, they could still remember a similar amount of words from before. Their memory was “just as good as it was before sleeping,” says research supervisor Axel Mecklinger.

In comparison, those who watched the DVD performed significantly worse when it came to remembering word pairs.

Sleep spindles
The researchers also used an EEG to measure the brainwave activity of those who slept to see if there was a correlation with how they performed in the memory test. They focused on the role of the hippocampus, a part of the brain where memories are consolidated and transferred into long-term memory storage.

Sara Studte, a graduate specialising in neuropsychology, who also worked on the research says: “We examined a particular type of brain activity, known as ‘sleep spindles’, that plays an important role in memory consolidating during sleep.” A sleep spindle is shown on an EEG as a short burst of rapid oscillations. The findings confirmed that the greater the number of sleep spindles, the better a person can remember things.

Although the number of participants in the study was limited, Mecklinger still feels the overall findings are telling. He concludes: “A short nap at the office or in school is enough to significantly improve learning success.”

*Studte S et al. Nap sleep preserves associative but not item memory performance. Neurobiology of Leaning and Memory. Feb 2015.