Discussion
The present study adds to the existing literature on nap optimization for cognition by comparing 10 min, 30 min, and 60 min naps on their benefits to memory encoding, as well as extending test intervals to investigate self-reported and objective metrics of mood and performance. We found that all nap durations showed benefits for self-reported alertness and positive mood up to 240 min after napping. Only naps of 30 min significantly benefitted memory encoding compared to wake, and sleep inertia did not account for the differences in encoding performance. Factors that may have contributed to these effects, including extent of prior sleep deprivation and test delay interval, are discussed.