Marathon runners can be compulsive beasts by nature. So it should be no surprise that a rising number of runners have decided to take their marathoning to the next level. Not by running ultra marathons, races that exceed the 26.2 miles of a standard marathon, but by running multiple marathons within a short period of time.

I should know. I’m one of them. This year I decided to dip my toe into the world of multiple marathoning by doing what I soon learned was a “classic double” — running two marathons back to back: the Chicago Marathon on Oct. 6 and the New York City Marathon on Nov. 4.

To be clear, many marathon organizers, including those in Chicago and New York, do not encourage it. Run our marathons, they say, but if you want to do more? Well, be careful.

My sister, an accomplished running coach, rolled her eyes when I told her my plans. “You’re an idiot,” she said. Siblings.