Britney Spears “Toxic” Cardio Workout By The Fitness Marshall • September 21, 2015 Is there a better song to do your cardio to? I think not! Let’s get dancing and forget about the fact that today is Monday. WATCH MORE: Nicki Minaj Cardio Workout WATCH MORE: Rihanna Cardio Workout *This video was originally published on The Fitness Marshall’s Youtube channel. For more workout videos visit www.youtube.com/user/TheFitnessMarshall.