Generally, the unloaded muscle is used as a main power source fatty acids from fat. However, if we start training, swim, skate ... burn the fat need more energy faster delivery than in dormancy. Fats, however, can not meet this requirement. Fat is too slow. At this point, focus on stressed muscles sugars-carbohydrates. He likens it to gasoline and diesel. Carbohydrates (glucose), like gasoline, are much faster and more dynamic source of energy than the quiet and slow or fats. diesel. The diesel engine is worth a longer relaxing transportation, but Benz is more suitable for shorter-term, more "aggressive" driving.
Athlete, or a person accustomed to regular strenuous physical activity, places much greater demands on carbohydrates as an energy source. During exercise, or any intense activity, the body uses the "fast" calories from carbohydrates. In resting conditions or during low activity, in which so much fitness not rise significantly and heart rate, "going in fat". Carbohydrate stores are very poor, they will last us for a short time. But the fat and lean individuals have always had plenty of energy. Body stressed demanding, long-term and often repetitive physical activity removes large amounts of storage forms of carbohydrates stored in the form of glycogen in the muscles and liver. Because he knows that this limited power source will need it again for the next demanding physical work, learn in resting conditions, even when moving at a lower intensity, more use of fats. See the example in the article bicycle ride. That's exactly what we aim for weight reduction - burn in increased fat reserves. Trained people are far better for burning fat and much less risk of being fat.
Each person has a chance suitably chosen, regular physical activity gradually teach the body to burn fat. Unfortunately, we do not get this ability within 1-2 weeks. The method of obtaining energy, the nature of metabolism varies gradually and over a longer period of time. During the half year to year, regular physical activity, we can feel each other clear changes. However, when we cease to increased loads, gradually returning everything back. This indicates that, as for one month with practice, it will lose in one week ... learn the body to burn fat lasts 4x longer than lose this ability.