Cortisol: The Muscle-Eating Hormone
When your body is put under stress, whether by an angry dog chasing you during a run or an
intense lifting session, it naturally produces a stress hormone called cortisol.
Cortisol is a lifesaver in certain situations, keeping your body from going into shock when
traumatized. It also helps energize protein synthesis following exercise. But in high chronic levels,
cortisol is catabolic. It breaks down muscle and contributes to increased belly fat. Studies have
shown that obese people have significantly higher levels of this hormone than thin people. Unfit
people typically have more cortisol than fit people do. More cortisol means less of the anabolic
hormones like testosterone and growth hormone.
The body releases cortisol in response to any type of stress, including exercise. Overtraining is a
type of body stress that triggers a great amount of cortisol to be released. This is why adequate rest
and recovery are so important to the training bodybuilder. To control levels of cortisol, the dieting
bodybuilder should consume enough protein, including branched-chain amino acids to enhance
recovery and get good sleep, at least 8 hours, and carefully plan workouts to ensure adequate
rest to avoid overtraining.