The Shake It Out Songfacts reports that the song is about having a hangover and wanting to shake it out. Speaking to XFM radio, Florence explained: "I wanted to just shake something out, shake out these regrets, shake out these things that haunt you. It was one of those songs that came in about half an hour and when you've got a hangover, it is almost like a hangover cure. You're like, thank you!"
She continued: "I don't want everyone to think that I always write songs with a hangover! Cause I don't, I really don't. .