Quote Originally Posted by Eladrin View Post
Using a rest shrine is conceptually the equivalent of resting for eight hours, which is why non-permanent effects go away when you use one. At the end of the eight hours, fleshies are healed by their good night's sleep, and warforged are partially repaired.

Warforged do not naturally heal over time (though on the bright side, they don't bleed out either if rendered unconscious), which is why they do not receive their level in hit points after a night's rest in the equation.
Well. That makes sense.