Forty-five minutes of snoozing during the day can really help your brain function and memory, according a study conducted by researchers from the Experimental Neuropsychology Unit at Saarland University in Germany. A quick nap allows your brain to retain what it learned during your waking hours.
The researchers used 41 study subjects. Each participant was shown a list of 90 single words and 120 unrelated words, or word pair. "A word pair might, for example, be 'milk-taxi.' Familiarity is of no use here when participants try to remember this word pair," study leader Alex Mecklinger said, according to Medical News Today (MNT), "because they have never heard this particular word combination before and it is essentially without meaning. They therefore need to access the specific memory of the corresponding episode in the hippocampus."
The participants were immediately tested on how well they recalled the words. Then, half of the study subjects were sent to watch a DVD, while the other half were told to nap for up to 90 minutes. The nappers were hooked up to an electroencephalogram (EEG) that measured "sleep spindles" - a gush of activity in the hippocampus, which plays a large role in memory consolidation.
"We suspect that certain types of memory content, particularly information that was previously tagged, is preferentially consolidated during this type of brain activity," Mecklinger said, according to MNT.
After the nap or DVD, the study subjects were again asked to recall the words. Those that took a nap were able to remember word pairs five times better than those who watched the DVD.
"Positive correlations were observed between spindle density during slow-wave-sleep and AM posttest performance as well as between spindle density during non-REM sleep and AM baseline performance, showing that successful learning and retrieval both before and after sleep relates to spindle density during nap sleep," study authors wrote."Together, these results speak for a selective beneficial impact of naps on hippocampus-dependent memories."
Siesta, anyone?
