WHAT IS INSANITY? INSANITY® is a 60-day, cardio- based, total-body conditioning program that’s the most intense workout ever put on DVD. Fitness expert Shaun T drew on his collegiate track-and-field training, plus his subsequent years of experience as an elite trainer, to create a program that takes total-body conditioning to an extreme level. Just as P90X® is the height of resistance training, INSANITY is the pinnacle of cardio training. WHY IS IT EFFECTIVE? Interval training allows you to beat the “stress adaptation response,” which is what happens when your body gets used to exercising at one level of exertion and stops improving. An interval workout includes a set where you perform at your maximum, followed by one of lower intensity, with the cycle repeated to achieve a cumulative effect.