Book excerpt: A complete guide to the most intense interval training you can handle! Your pizza was delivered in 30 minutes or less, why not work off the calories in the same amount of time? High-Intensity Interval Training (HIIT) increases your glucose metabolism, and most of the exercises don’t even require equipment. This guide offers step-by-step instructions for highly intense workouts. It will also give you plenty of tips to prevent injury, and pre-planned exercise routines that are sure to help you get fit fast. Modification options allow you to make workouts harder or easier based on your fitness goals. Intensify your workouts and see results!