Stalwart, Improved (Feat), Tenacious Survivor (Feat), Survivor (Feat)
Benefit: You reduce all environmental damage you suffer by 4 points, as though you had 4 points of ER or DR of the appropriate type to resist the environmental damage in question. Environmental damage is damage caused by the environment, and not by a creature, or by an effect designed by a creature (such as a trap). A rock falling off a cliff during a storm is environmental; a rock thrown by a troll is not. (See Environmental Effects for details.)
This protection increases by an additional +1 per experience tier you have after the first (i.e. 5 points at 6th level, 6 points at 11th level, 7 points at 16th level, etc., to a maximum of 10 points at 31st level).
This protection is in effect even if the character falls unconscious or is rendered helpless.
This protection can be stacked with any other form of protection against environmental damage, but does not stack with any source of DR or ER that provides mitigation against normal damage.
Special: You may sleep in light, medium or heavy armor without becoming fatigued.
Normal: A character without this feat who sleeps in medium or heavier armor is fatigued the next day. All creatures are normally susceptible to the effects of weather and other environmental conditions.