08 July, 2011
How Does Exercising Burn Fat?
Exercise is an integral part of any weight-loss program. Resistance exercises strengthen and tone the muscles while aerobic exercises condition your cardiovascular system and flexibility exercises increase your range of motion. Additionally, all types of exercise burn extra calories which, in turn, burns body fat. When combined with a healthy diet, you can burn more fat than you would with diet or exercise alone. To understand how exercise burns fat, you should understand how the body uses energy.
Your metabolism is similar to the production floor in a factory and runs in a continuous cycle, 24 hours a day. Tiny structures within the cells, called mitochondria, convert glucose into a fuel called ATP which the body then uses to run all of its processes, the same way a car uses gasoline. The mitochondria get the glucose from sugar in the blood stream, which comes from the foods we consume. The amount of ATP you need depends on how active you are, your body size and gender. The amount of ATP you need also influences how much food you need to consume in a given day.
Body fat is stored energy. The mitochondria converts most of what you eat into energy but if you consume more than you need in a day, your body stores the excess for later use. Fat cells are like pouches, which expand as they fill with fat. If you consistently consume more energy than you need, your fat cells will continue to enlarge. If you store more fat than the existing cells can hold, your body will make more cells.
Aerobic Exercise Fat Burning
Aerobic exercises raise your heart rate for a prolonged period, such as with running or a dance class. As stated before, the mitochondria in your cells make ATP based on your energy needs. If you are sedentary, you only need the minimum amount of energy and the mitochondria don’t make as much ATP. Aerobic exercise works your muscles and increases your heart and breathing rate, all of which require more energy. During an aerobic session, the mitochondria will tap into the blood sugar stores to get the sugar they need to make ATP. When the sugar stores run low the body breaks down, or burns, body fat and use that to make ATP.
Anaerobic Exercise and Fat Burning
Anaerobic exercise burns calories but it does not consistently raise your heart rate the way aerobic exercise does. For example, your heart rate may fluctuate during a yoga or weight training session, but it will not stay consistently high the way it would if you were running. As with aerobic exercise, these exercises will increase the immediate energy demand and cause you to tap into your fat stores when your sugar stores run low. They won’t, however, burn as much fat per session as aerobic exercises. The benefit of anaerobic exercise is in the long-term fat burning. These exercises build muscle tissue, which has constant energy needs. The more muscle mass you have, the more ATP your body needs.
- Mayo Clinic: Metabolism and Weight Loss: How You Burn Calories
- TeensHealth: Metabolism
- “Physiology of Sport and Exercise” Dr. Jack H. Wilmore, et al; November 2007
- Jupiterimages/Photos.com/Getty Images