I'm interested in relationship between stress and brain function.
Mechanism of brain is very intersting because brain is very accurate organism.
When we feel about fear, stress, brain alart to amygdala in brain, then amygdala make signal to hypothalamus then hypothalamus makes singnal to hypophysis ,then hypophysis make signal to adrenal gland then adrenal gland release cortisol which is stress hormone.This route is called "HPA" .
Cortisol is circuited via blood around our body then affected many organ including brain.
Cortisol is good when emargence situation was happend, but when we continuously feel stress alltime, cortisol level is always high and it is bad for brain, especially for hippocampus which is important for memory.
My favorite book "Method of usage of waking up early" said that 3 important issue for health is "sleep 7 hours", "good food" and "good exercise". The author kisou kubota has jogging 3 days per week since he was 46.
I bought this book about 5 years before and has continued waking up about 4:30 AM, continuing jogging (recently walking or something like that) and eating breakfast with rice with fermented soybeans and yogurt.
This book said that good exercise stimulate prefrontal area which is major player in brain. And good exercise makes us good tiredness that make us sleep early.
Like my experience, during running, my brain works actively because I must watch if car's coming or bycles suddenly come.
And after running and sometimes one cup of beer!, good sleepiness come and sleep soon. This book said good sleep reduce level of cortisol. From my experience, when I waked up after good exercise, my brain is very fresh and keep good condition,so this triangle is very good for me.
And recently, I read Sparks which said almost same things.
So thinking stress from the point of brain mechanism is very intersting thing.