“Aerobic” exercise is typically touted as a great way to burn a lot of fat. While this is not necessarily incorrect, it can be misleading. For example, at about 25 percent of aerobic capacity (i.e., low intensity exercise), fat is the primary source of fuel, but you are not burning a significant number of calories. If your goal is to lose weight, the key consideration is the net deficit in calories, not where the calories come from. As exercise intensity increases, the number of calories burned also increases. Therefore, while it is true that fat contributes a greater percentage of the total energy during lower intensity exercise, at higher intensity exercise, the total quantity of fat utilized may be greater for exercise performed for an equivalent period of time.
If you do not have a specific goal in mind, but simply want to improve your overall health, the American College of Sports Medicine recommends moderate intensity physical activity performed for at least 20 to 30 minutes, excluding time spent warming up and cooling down, 3 to 5 times a week. If, on the other hand, you are training for some type of competitive event, make sure that your training program emphasizes the type of activity involved in that event. For example, if you are training for a high rank testing where you will have to spar many rounds against fresh opponents, engaging in a power lifting training program three days a week will not make the best use of your time. You need to engage actively in running, biking, and swimming. Finally, if your goal is to lose weight, caloric deficit is key. You should aim for a caloric deficit of about 500 calories a day through decreased energy intake, increased energy expenditure, or a combination of the two. Although there are numerous types of exercise that are effective for weight loss, a combination of regular aerobic exercise and resistance training is a good place to start.