A must read...

You will find there great information by Peter Levine.

Marc Lewis, PHD
Understanding Addiction
A new perspective linking Brain, Behaviour, and Biography

Gabor Mate, MD
When the Body Says No
The Cost of Hidden Stress

Check out Lisa Feldman Barrett's book, How Emotions Are Made

Check out Joseph Ledoux's book, Anxious

Systema is a unique Martial Art based on holding no tension in the body.