In the simplest sense, cardio will help you burn fat because when you exercise, your body is using energy and burning calories, Davon said. To fuel your workout, your body will draw from its energy (calorie) stores: glycogen, or the glucose that your body stores after consuming carbs, as well as fats.
It follows that the most effective form of cardio is the one that increases your heart rate the most and burns the most calories. That means high-intensity interval training (HIIT), said Davon and fitness coach Nick Leyden, MS. "HIIT workouts burn a lot of calories in a short time and keep your body burning calories throughout the rest of the day, at a higher rate than just doing 30 or 45 minutes of steady-state cardio," Nick told POPSUGAR. That's due to the EPOC effect (excess postexercise oxygen consumption), a mode your body enters when it's trying to replenish the "oxygen debt" you have after a hard workout, Nick explained. Your body draws in more oxygen even after the workout is finished, which leads to slightly more calories burned for one to two hours after your workout.
HIIT workouts are more efficient as well. You can burn about the same amount of in-workout calories as you do during a longer, steady-state session, Davon told POPSUGAR, but in less time. This beginner's HIIT workout is a good place to start.
Image Source: Getty / Martin Novak