The Interval Training Workout, cowritten by a doctor and a certified trainer, shows how interval training can be done practically anywhere and benefit anyone who wants to get healthy. The training has three key components: -Interval training workoutswith brief repetitions of intense exercise alternating with intervals of rest; (extended) workouts: longer weekly sessions which allow certain biochemical and muscular adaptations that improve fitness and burn fat; and-active rest days: steady, comfortably paced exercises that help the body rest and recover while still burning calories. The book also offers specific customizable programs for training and tips for assessing performance and tracking progress.