Article by Jane Porter on fastcompany.com
References separate research work at Yale, Harvard, and Berkeley.
Key points:
1. Chronic stress generates long term changes in the brain that lead to anxiety and mood disorders.
2. Stress literally shrinks the size of your brain
3.There are some types of healthy stress.
4. Mindful meditation and exercise have been shown to increase grey matter in key parts of the brain.
http://www.fastcompany.com/3040734/how-to-be-a-success-at-everything/how-stress-shrinks-our-brains-and-what-to-do-about-it
Hosting
In the short-term cortisol presumably helps the brain to cope with the life-threatening situation. However, if neurons become over-loaded with calcium they fire too frequently and die they are literally excited to death.