Cortisol, also known as the ""stress hormone"", because of its response to stresses such as: emotional, trauma, infection, surgery, and perhaps the most common to bodybuilders, the stress of physical exertion.
Coritsol is a steroid hormone. It is a four ringed structure like testosterone, but has a far different impact on the body. Coritsol, when released into the bloodstream, reacts throughout the body to control the body’s supply of carbohydrates, fats and proteins. It also suppresses the immune system, preparing us to carry on in the face of life’s various stresses.
Coritsol is released by the adrenal cortex, which is located above the kidneys. Parvocellular neurosecertory, cells that are found in the anterior pituitary gland in the brain, control the adrenal cortex and determine whether a stimulus is stressful or not, as defined by the release of cortisol. These neurons lie in the hypothalamus, namely in the periventricular zone of the hypothalamus and release a peptide called corticotropin-releasing hormone (CRH) into the blood. CRH travels the a short distance into the anterior pituitary, where within a small time frame, it stimulates the release of corticotropin, or adrenocorticotropic hormones (ACTH). ACTH enters the blood stream where it stimulates cortisol release.
Blood levels of cortisol are, in general, regulated. As mentioned earlier, cortisol is a steroid, whose precursor is cholesterol. Thus, cortisol is lipophilic, or a "fat-loving" molecule, which can easily pass through membranes and readily cross the blood-brain barrier. In the brain, cortisol interacts with specific receptors that lead to the inhibition of CRH release, ensuring that circulation cortisol levels do not get too high. Interesting enough, neurons with cortisol receptors are found throughout the brain, and not just in the hypothalamus.
Once cortisol is released into the blood stream, it has the potential to decrease amino acid transport into the cell. This decreases anabolism and stimulates protein breakdown, where amino acids are the result, this happens in all cells except the liver. The circulation delivers these freed amino acids to the liver for gluconeogenesis -- the creation of glucose from a non glucose source. Coritsol also serves as an insulin antagonist, by inhibiting glucose uptake and oxidation.
In instances where there are elevated and extended levels of serum cortisol, this can lead to excessive protein breakdown, tissue wasting and negative nitrogen balance. All of which are counter productive to bodybuilders.
Bodybuilders go to the gym to build their muscles, which is named hypertrophy. They must stay in a positive nitrogen balance for muscles to grow. Insulin is also important as it helps drive much needed nutrients into the cell, especially after a workout. There is discussion that two supplements, glutamine and phosphatidylserine are used to produce an anticortisol effect, however, I believe all this comes down to a matter of personal opinion. To keep your cortisol levels low, there are a few choices, two of which are, you could resort to medication or try to stay relatively stress-free. Generally speaking, the less stress there is, the lower your cortisol levels, but keep in mind, there are times when being stress free is difficult, namely after a workout.
- Kurt Kuhn - www.FUSIONBodybuilding.com