Increase your CON score by 1 to a maximum of 20.

You do your best work under extreme physical duress. When your Hit Points fall below 1/4 of your maximum (rounded up), you gain the following benefits:

• You have advantage on all STR checks and saving throws
• You ignore all effects of Exhaustion that don't kill you
• Your speed (walking, swimming, flying and other special speeds) increases by 50% (rounded down)
• You are immune to the frightened condition

When your Hit Points remain above 1/4 of your maximum for 10 minutes the effects of this Feat end and you gain a level of Exhaustion.