The Metabolic Afterburn
When people speak about adrenaline, the common term used to describe this hormone is Fight or Flight. This exact concept is how weight training is successful for those whom perform it properly, partial to their goals and aspirations. Our bodies are designed to use sugar for energy in this Fight or Flight mode, which is quickly depleted and causes a production of lactic acid. When lactic acid (hydrogen, actually) builds up, the body begins to slow down and releases testosterone and human growth hormone to work through this stoppage.
So let’s examine an intense resistance-training workout. After 10-15 grueling, intense sets, your muscular system is weakened and damaged and your body is exhausted. Now the ever-important rest phase begins. The rest period allows the body to rebuild, regenerate, and recycle energy. Since sugar stores are now depleted, energy from fat is used to repair the body and partly regenerate sugar reserves.
Wait, I’m burning more fat while resting then exercising? YES. Not just calories; you are burning fat for recovery. Also, you have caused your body to use fat instead of sugar for fuel. So your body that was operating at a certain level is going to repair itself and become more efficient at its normal operating speed. This is also why weight training is far superior to cardiovascular exercise, in terms of the lasting effect on the body.