The elements are slaves to no being. One must learn to ask for their aid, the elements offer power to the humble. This is why no one is truly a master yet everyone is a student..
~The Apprentice of the Elements
This was considered a while back, but it was decided it would discourage interaction and roleplay, encouraging people to just go out and fight, get tired, lay down and sleep (preventing any other actions) only to get up, go out and fight, get tired, sleep, repeat.
They're free to lie down somewhere and enjoy the increased energy gain rate as normal. We're not going to give extra rewards for and encourage anti-social activity (or inactivity, I should say).