Pathfinder 1e Feat: Endurance

Endurance

Harsh conditions or long exertions do not easily tire you
 Prerequisites:
 Benefit: You gain a +4 bonus on the following checks and saves: Swim checks made to resist nonlethal damage from exhaustion; Constitution checks made to continue running; Constitution checks made to avoid nonlethal damage from a forced march; Constitution checks made to hold your breath; Constitution checks made to avoid nonlethal damage from starvation or thirst; Fortitude saves made to avoid nonlethal damage from hot or cold environments; and Fortitude saves made to resist damage from suffocation.   You may sleep in light or medium armor without becoming fatigued.
 Normal: A character without this feat who sleeps in medium or heavier armor is fatigued the next day