From your brain to the bottom of your feet, this handy infographic details what you're signing your body up for when you run a race

By Charlotte Hilton Andersen
June 08, 2015
Corbis Images

Some of us do it to get healthier, others do it as a way to lose weight loss. Still others just want the thrill of doing something they once thought impossible. But no matter how you look at it, running a marathon is a huge accomplishment. All the training, sweat, and, yes, tears that go into running 26.2 miles make it one of the toughest things you can do, both mentally and physically. (See 17 Things to Expect When Running Your First Marathon.)

But what does race day actually do to you? You may have heard that Pheidippides, the ancient Greek who ran the first marathon, dropped dead after his epic run. And while it's true that four(ish) straight hours of exercise has a huge effect on your whole body, the latest research thankfully shows that not only are you unlikely to drop dead (Pheidippides was in the middle of a war, after all), but that running has powerful life-long benefits-as long as you do it sensibly.

First off, you burn ten times more energy while running a marathon than you would doing your normal activities. The average female runner will torch about 2300 calories over the course of those 26 miles. And while you'd think your legs would bear the brunt of it, you'll feel the effects of your run from head to toe and then some. (Don't worry, Your Brain Forgets the Pain of Your First Marathon.) Before you register for the big race, here's a sneak peek at what you're actually signing up for.