Kevin Hart took the stage at the Wall Street Journal’s Tech D.Live conference with plenty of professional accomplishments to talk about, from his national comedy tour that sold over 1 million tickets to his film, Night School, that brought in nearly $100 million in worldwide box office.

Here’s one feat that might have escaped notice: Hart said he ran the Chicago marathon on the same day that he performed a comedy show in Nashville.

The comedian committed to the 26-mile endurance event to send more kids to school. It was only later, Hart said, that he realized he was scheduled to perform later that night.

“I couldn’t feel my legs — true story,” Hart joked. “It was a horrible marathon. It was one of those marathons, that while running it, you just question your life.”

Hart said he promised himself “he crowd is ever going to know how much pain I’m in,” even though he actually felt his legs go out from under him at one point during his comedy routine (the audience thought it was part of the act.)

The comedian turned philosophical, saying that the endurance feat illustrates a key to his professional success.

“I’ve made it this far by constantly pushing myself, by constantly putting my foot on the gas,” Hart said.

The 26-mile ordeal of a marathon was a mental battle, where he persevered despite that part of his brain that kept insisting that he couldn’t go on.

“There’s so many things in life that say, ‘You can’t do it,’ and another part of you that says you can,” said Hart. “That constant tug of war is why I sit where I sit today.”