Starvation

Starvation
"You've been burning through energy without really having any, and right here is your receipt of the transaction. You have suffered Starvation damage."
Treated with	Nothing
Cause	Going under 2000 Energy
Penalties	None
Rewards	None
Go to Wounds page

Going under 2000 Energy will cause periodical HHP damage. Initially very slow, especially if you're barely under the threshold. If you let the total energy get even lower you eventually start taking heavy damage even when simply idling.

Only heals if your energy increases to over 8000 energy. Will not heal by sleeping, only if you are logged in.