Do Elves sleep?

[Anarya SilverBranch]

The thing is, elves don't really sleep. It's more like resting. They fix their eyes on something beautiful and think about elvish things. Like in the two towers When Aragorn, Legolas, and Gimli are chasing after the orcs, it says that while they are running
Leoglas would rest,

If sleep it would be called by men, resting his mind in the strange paths of elvish dreams, even as he walked open-eyed in the light fo this world.- The Two Towers

So you see its not really sleeping.