Naps Benefit Memory, Alertness, and Mood.

A recent study examined how mid-afternoon naps of differing durations benefit memory, alertness, mood, and sleepiness. 32 young adults with habitually short sleep of less than 7 hours took naps of 10 min, 30 min, and 60 min as verified with EEG. A 10-min test battery was delivered at a pre-nap, and at 5 min, 30 min, 60 min, and 240 min post-nap for each nap condition. The results indicated that the 10, 30, and 60 minute naps all increased positive mood and alleviated self-reported sleepiness up to 240 min post-nap. Compared to waking, only naps of 30 min improved memory. Improvements in alertness were moderate, and sleep inertia was observed for the 30 min and 60 min naps but was resolved within 30 min after waking.

In summary, naps ranging from 10 to 60 min had clear and lasting benefits for positive mood and self-reported sleepiness/alertness. Cognitive improvements were moderate, with only the 30 min nap showing benefits for memory. 30 min naps appear to have the best trade-off between practicability and benefit.