There is research going on with every aspect of our brains that when we search for all the parts, we can see a much clearer picture of what the challenge looks like for Post Traumatic Stress Disorder(PTSD).
This is a long read, but if you take it in in small bites, you can get through it. The formatting of the article could have been done a little better, but the information is interesting.
With PTSD this is a highly used function of the brain, so understanding how it works will help us to understand how it malfunctions.
When I would go out alone, just as I started my first round of therapy, I would be exhausted when I would get home or somewhere I felt safe because I would be on extreme high alert for threats. I would actually be sweating from the stress, and sometimes I would have an anxiety attack, but I would always be physically exhausted from the tenseness in all my muscles. It isn’t as bad now, but I do occasionally have that intense of an experience when I am in a large crowd.