Do you look at the treadmill and think, “Treadmill…? More like DREADmill,” and then laugh at your own cleverness? Do you fall into a mind-numbing boredom ball while using the conveyor belt of monotony? This high-intensity interval routine will challenge your body and keep you brain engaged, boosting your fitness level as the minutes fly by. Interval training is the best when it comes to cardio conditioning.