Easy check the elves hand book, it is also the reason elves are immune to sleep spells they simply do not sleep their for a spell that puts them to sleep is useless.
for some great elf info check
http://www.myth-drannor.net/Dlabradd...ome%20page.htm but remember it's general to most elves and some is specific to the forgotten realms and may or may not apply to Layonara. IE history is diffrent.
Unlike the other races an elf does not sleep. Instead to rest and refresh both mind and she enters a state of deep meditation – the reverie or trance. The elf reviews her memories and without this process it is doubtful an elf could remember all the things that happen to her in her very long life. Unlike dreaming this is a process of examining memories from outside, reviewing rather than reliving. During trance an elf's eyes are open, but she is unaware of her surroundings till she is aroused (similar to being woken).
A pregnant elf enters reverie in the mid to late stages of the pregnancy and stays in this state to commune with her child, teaching it language and much of the elven inheritance. This may account for the fact that even very young elves are well behaved and communicate well.
An elf will be refreshed in both mind and body after only 4 hours of trance. Their bodies are also renewed for another day, having healed as fully as a sleeper does after 8 hours of good rest. If this trance is part of an 8 hour period of rest it is sufficient for them to relearn any spells. Elves do not need to actually sleep to relearn spells. Elves entering reverie in trees have been known to lash themselves to the branches with vines or ropes - their muscles and bodies can totally relax, much the same as the bodies of dreamers.