Circuit training rotates through a series of moderate-intensity exercises that target different muscle groups with almost no rest between each one. HIIT, on the other hand, can involve a single exercise or multiple ones that are performed at maximum intensity for short intervals, followed by rest.

A personal trainer breaks down 11 of his top-recommended interval training exercises to melt belly fat and slim down your midsection.

For instance, if your goal is to lose fat, you should also start strength training. Strength training helps your body burn fat, not just during your workout but long after it's complete. Putting on muscle affects your body composition and your metabolism in significant ways.