Jim Sullivan is a big shot in the national electric union but it's his hobby that's truly shocking.

The 55-year-old has completed 240 marathons and apparently that wasn't enough. So, now, he's into ultramarathons, which are usually 50 or 100 miles long and involve extreme courses.

He describes to Growing Bolder what the appeal of these endurance events are and why the average competitor is 44 years old.

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