Issue link: http://cp.revolio.com/i/1129210
Page 14 | Abby's Magazine - www.AbbysMag.com I've read that if I want to burn more fat and lose more weight while exercising, I need to exercise in the fat burning zone. Is this true? The short answer is, no, not really. Although it's technically true that exercising in the so-called "fat burning zone" (at a lower intensity level of about 60% to 70% of maximum heart rate) does use a higher percentage of fat calories for fuel, the overall total calories burned is still fairly low. The reason is simple. Fat is a slow-burning fuel that requires oxygen to convert it to a usable energy, so it's great for long, steady, slow exercise, like backpacking, or cycling a long distance. Most people have enough stored body fat to fuel low level activity for days and days without running out of energy, but if you want to go fast, work all-out, or burn the most calories per minute, you need to rely on the faster-burning carbohydrate (glycogen) for energy. Converting fat to fuel takes longer, and requires lots of oxygen. In the strictest definition, this is called aerobic metabolism. High intensity training (HIT), on the other hand, tends to use anaerobic metabolism, or glycolysis, to quickly convert stored glycogen to energy for exercise. This process can happen with little to no oxygen. The downside of anaerobic metabolism is that it has a limited supply, and when you run out of stored glycogen, typically around the two hour mark, you'll have to slow down and start using aerobic metabolism or refill your glycogen stores with some easy to digest carbohydrates. To further complicate the fat-burning zone theory, you need to recognize that when we exercise we use a combination of energy systems throughout the workout. Athletes are rarely exclusively in the aerobic or anaerobic zone. Now to the real question. If your goal is weight loss, and burning calories is the way you are trying to lose weight, you are better off exercising at a higher intensity 2-3 times per week, and burning more overall calories from both fat and stored glycogen. While it is true that you burn a higher percentage of calories from fat in the low intensity "fat burning zone," you still burn more total calories, and more calories from fat, at a higher intensity. Pushing your pace, alternating bursts of high and low intensity (interval training), and adding some all-out efforts forces you to activate the anaerobic system (70-90% of your maximum heart rate), which results in a greater number of total calories burned during your workout, which is what ultimately determines fat loss from exercise. Calories Burned in Fat Burning Zone Still not convinced that the fat burning zone doesn't really burn more fat? Let's do the math. The chart below details the fat calories expended by a 130-pound woman during a typical exercise session. In this example, the woman burns more total calories and more fat calories at a higher intensity. Calories Burned at Low and High Intensity Low Intensity (60-65% MHR) High Intensity (80-85% MHR) Total calories burned per min. 4.86 6.86 Fat calories burned per min. 2.43 2.7 Total calories burned in 30 min. 146 206 Total fat calories burned in 30 min. 73 82 Percentage of fat calories burned 50% 39.85% Source: The 24/5 Complete Personal Training Manual, 24 Hour Fitness, 2000 The Skinny on the FAT BURNING ZONE