This spell enhances the natural hardiness and stamina of the affected creatures by rendering them virtually immune to fatigue or exhaustion. During the casting of the spell, the caster must touch each creature to be affected. While under the spell's influence, the subjects may force march with no penalty, engage in up to 12 hours of hard labor per day with no fatigue (or up to 16 hours with moderate fatigue), and gain a +4 bonus to Strength/Stamina or Constitution/Fitness checks. In addition, the subjects gain a +4 bonus to saving throws against spells or magical effects that cause weakness, fatigue, or enfeeblement. Finally, an affected creature's fatigue rating (from Player's Option: Combat & Tactics) is doubled, and the subject gains a +4 bonus to his saving throws to recover from a fatigued or exhausted state.