Inspired by Refinery29’s Money Diaries and The Cut’s Sex Diaries, welcome to The Runner Diaries, where we’re sharing a behind-the-scenes look into a week of training with runners of varying ages, paces and GPS coordinates. This week, we have 36-year-old Marnie Kunz — a run coach, social media marketer/consultant, and founder of Runstreet, a running and event company based in New
