How Stress Affects The Body
When the body is faced with a stressful situation, it initiates the stress cascade:
Cortisol is produced to help get the body back in a steady state of homeostasis in order to overcome the situation at hand. There is a redistribution of energy toward critical organs like the brain and heart and away from the digestive system and reproductive system.
If the threat is resolved, the system is shut-down, and there is no long-term impact on your health. But, lots of stressors don't just go away quickly.
When the threat cannot be overcome or one is chronically exposed to stress, the system is over worked and is harmful to the brain and heart. The immune system is suppressed, which is not a problem if the stress is only for a short time...but when faced with chronic stress we become vulnerable to biological attacks on our bodies. The production of cortisol hampers the proliferation of T-cells and the function of white cells.
The Hypothalamus stimulates the anterior pituitary with corticotropin, which causes the release of ACTH, which then stimulates the adrenal to secrete cortisol.