Imagine you’ve worked hard. You’ve worked long. Mentally, physically you’re done.

But then I offer you $1,000 if you can keep going for another 10 minutes.

And suddenly you’re good to go.

Hold that thought.

Mental toughness. Determination. Willpower. Perseverance. However you describe it, the ability to push through mental and physical fatigue to achieve long-term goals is often what sets successful people apart. When others stop trying, the last person to give up—especially on themselves—is often the person who succeeds.

But why do some people keep going when others won’t? In part because they understand, if only intuitively, the 40% rule, a concept popularized by Dave Goggins in Jesse Itzler’s book Living With a SEAL.

The premise is simple. When our minds say we’re exhausted, fried

See Full Page