See You at the Finish Line by Sara Clement

Would you run a two hundred and forty mile race through the desert if it meant meeting the love of your life?

Paige Harrison is never quite satisfied. Having been a runner her entire life, she races through finish lines with ease. Too bad her love life doesn’t have the same track record. What will it take to get everything she’s ever wanted? The Moab240 entices her with its unrelenting elements and dangerous terrain, providing a distraction from her inner voice that longs for more.
Adam Ashford may be the greatest friend in the world. Forced by the laws of an IOU, he finds himself on the road to a two hundred and forty mile ultramarathon. When he asks a beautiful stranger at the starting line for a favour, his motivation improves drastically. Now it’s not about how fast he will run the course, but how far he will go for a woman he just met.