Recent studies have discovered a pathway that links stress to the onset of disease through the activation of certain genes.  The experience of psychological stress activates transcription factors that activate genes. In a study by Cole et al., it was concluded that GABA -1 transcription factor activates the interleukin -6-gene. This gene codes for a protein that activates the inflammatory response which directs an immune response to the site of the inflammation.  Chronic inflammation makes an individual more susceptible to diseases such as cancer , heart disease , and diabetes .
The levels of hormones in the body can be regulated by several factors. The nervous system can control hormone levels through the action of the hypothalamus and its releasing and inhibiting hormones. For example, TRH produced by the hypothalamus stimulates the anterior pituitary to produce TSH. Tropic hormones provide another level of control for the release of hormones. For example, TSH is a tropic hormone that stimulates the thyroid gland to produce T3 and T4. Nutrition can also control the levels of hormones in the body. For example, the thyroid hormones T3 and T4 require 3 or 4 iodine atoms, respectively, to be produced. In people lacking iodine in their diet, they will fail to produce sufficient levels of thyroid hormones to maintain a healthy metabolic rate. Finally, the number of receptors present in cells can be varied by cells in response to hormones. Cells that are exposed to high levels of hormones for extended periods of time can begin to reduce the number of receptors that they produce, leading to reduced hormonal control of the cell.
Small increases of cortisol produce positive effects like improved memory, reduced sensitivity to pain, and increased sustained energy. However, elevated cortisol levels from prolonged or chronic stress can cause side effects such as suppression of thyroid function, cognitive impairment, increased blood pressure, decreased bone density, and blood sugar imbalances. High levels of cortisol can also lower your immunity and inflammatory responses, as well as slow down the wound healing process. [Cortisol and The Stress Connection. John R. Lee, . and Virginia Hopkins Virginia Hopkins Health Watch, One-to-One Inc., 2009] Chronic stress leads to chronically high levels of cortisol in your body. This creates a need for higher levels of other hormones (. thyroid, insulin, estrogen and testosterone) in order to do the same job.