Endurance represents how worn down you are by constant activity. It goes up naturally, and goes down as you move or perform other physical actions. When you run out of endurance, you'll be unable to perform many taxing physical actions and will fall unconscious for a short period of time. The rate at which your endurance recovers is determined by your statpack, race, and the Fitness miniskill. This rate is increased slightly when you sleep. There are many other methods of recovering endurance through skills and items within Aetolia, however we will leave that to you to find out.