I'm sure we've all seen on tv adds claiming that Cortisol is the main cause of weight gain brought on by all the stresses in your life. Your morbid obesity is not your fault-you've been exonerated for the last box of Krispy Kremes you scarfed down. Fitness enthusiasts need to know how cortisol works so they can better manage it's effects. In fact, the cortisol levels during and after training could be the most important factor affecting the anabolic response to your workout. Put more simply, the greater damage to the muscle, the greater the cortisol response.

However, things get dicey when cortisol levels reach unnaturally high amounts that are beyond normal. That's when negative side effects, such as weight-gain, bone-mass loss, and increased abdominal fat, can occur. Too much cortisol can also cause more ominous problems, such as muscle tissue breakdown. Cortisol can wreak havoc with building new muscle by inhibiting it's growth.

Catabolic activity is what you want to avoid-that's muscle breakdown. Anabolic activity is what you're shooting for-the process of building lean muscle