Endurance

You gain a +4 bonus on the following checks and saves: Swim checks made to resist nonlethal damage; Stamina checks made to continue running; Stamina checks made to avoid nonlethal damage from a forced march; Stamina checks made to hold your breath; Stamina checks made to avoid nonlethal damage from starvation or thirst; Fortitude saves made to avoid nonlethal damage from hot or cold environments; Fortitude saves made to resist damage from suffocation. You may also sleep in light or medium armor without becoming fatigued.