In addition to lower blood pressure, cholesterol and stress levels, adding cardio training to your workout routine is a tried-and-true method of shedding a few extra pounds. When you perform cardio exercises, weight comes off as your body burns fat and carbohydrate stores for energy. How much of each you burn depends on the pace you keep up throughout your workout.
It's no secret that cardio workouts burn calories, but the actual metabolic process that dictates what type of calories you burn is a bit more complicated. Either way, if your main goal is to lose weight with cardio, it doesn't matter how many of the calories you burn come in the form of fat or carbs. Weight loss depends on calorie burn exclusively, not calorie composition.
Fat vs. Carbs
If it's important to you to understand how your pace affects what type of calories you burn during a run, consider that lighter exercise burns more fat relative to carbs. Conversely, keeping up an intense pace burns more carbs relative to fat. Generally, hovering between 50 and 70 percent of your maximum heart rate during a morning run will encourage your body to burn mostly fat, while pushing yourself about 80 percent puts you into carb-burning mode.
Fat Burn Zone Myth
Because you burn more fat relative to carbs at lower intensities, there is a myth in the fitness industry that suggests your appearance will benefit from remaining in this "fat burn zone" rather than pushing yourself to higher intensities. However, pushing yourself into the anaerobic zone causes you to burn more total calories, including more calories from fat, even if a higher percentage of them come from carbohydrate stores.
A 2012 study conducted by researchers in Sydney, Australia, found that men who performed sprint training for 60 minutes per week burned the same amount of body fat as those who jogged for seven hours per week. Interval training is an effective way to burn a serious amount of weight by alternating between periods of low-intensity cardio and high-intensity anaerobic work.
Steven Kelliher is an experienced sports writer, technical writer, proofreader and editor based out of the Greater Boston Area. His main area of expertise is in combat sports, as he is a lifelong competitor and active voice in the industry. His interviews with some of the sport's biggest names have appeared on large industry sites such as ESPN.com, as well as his own personal blog.