Try this slow-but-steady program if you can run or walk for 15 to 20 minutes at a stretch — or even if you're a walker who'd love to take it up a notch. "You'll ease into each distance-building run, so that you have fun as you gain momentum," says Troy Jacobson, official coach of Iron Girl and Ironman, who designed this plan exclusively for FITNESS. "It's simple: Every run, spend the time listed in a certain intensity zone to build your stamina." As you get fitter and more confident, cut back on walking and tack on more running until you hit 13.1 miles.
Must-Do Moves for Runners
Strengthen your lower body and get faster with these exercises.
Nutrition for Runners
Carbs are crucial to keep you energized. Fuel up without overdoing it with these meal plans and recipes.
Get a Running Buddy
Make FITNESS fashion assistant Marla Horenbein, 22, your running buddy as she trains for the MORE/FITNESS Women's Half-Marathon. "Short jogs have always been my way to de-stress, but after a recent breakup, I wanted to do something bigger."