@pineapplebrat: What's your vo2max?? Last week I added 4x4 intervals into my routine - 10 min warm up, 4 minutes hard, 4 minutes easy, repeated 4 times... 10 min cool down. The goal during the hard intervals is to get up around 85-95% of your max heart rate and the recovery lets you bring your HR back down. Cardio is something I've always had a love hate relationship with but it is pretty vital to upkeep for a healthy heart and lifestyle save this for your next run!