Taking naps may help boost memory and a 90-minute daytime snooze might help the most, a new study revealed.

Long-term memory refers to memories that stay with us for years, such as "what" memories - a car accident that happened yesterday - or "how to" memories, such as one's learned ability to play the drums or tear it up in a game of football.

Brain researcher Avi Karni of the University of Haifa in Israel instructed participants to learn a complex thumb-tapping sequence, then split the study subjects into two groups: one that napped for an hour, and one that didn't. The people who took an afternoon snooze showed sizeable improvement in their performance by that evening.

After a night's sleep the two groups were at the same level, but the group that slept in the afternoon improved much faster than the group that stayed awake. An additional leg of the study showed just how much faster a 90-minute nap could help lock in long-term memories.