Abbreviated GP.
The Grace Period determines the period, in turns or rounds, between the imposition of exhaustion penalties. It is calculated as 6+Dice+Stat. A character can perform a number consecutive (and/or simultaneous) actions equal to their Grace Period without penalty.
The relevant Stat for physical exhaustion is Endurance.
The relevant stat for mental exhaustion is Willpower.
The relevant stat for emotional exhaustion is Courage.
Typically, only the Grace Period for physical exhaustion is listed on the Character Treatment, as this is by far the most common sort of exhaustion.