I know a lot of people don't like competition but I have found Judo competition to be very helpful dealing with the adrenaline dump. When I was younger I would get an uncontrollable rush of adrenaline but now I remain relatively calm.
After a several years of Judo I had someone try for 10 minutes straight to intimidate me by posturing, circling around me, staring, talking smack etc. I remained calm and I had a very slight adrenaline dump but it was just enough to quicken my reflexes a little, it didn't take control over me. It was similar to having a couple cups of coffee. The key thing I think is actually being ready to fight if you have to, I was comfortable with that prospect.
I was calm with him and was even slightly arrogant towards him at a certain point. At the end I invited him to come to my wrestling class and we could spar, he promptly left. I think wrestling works better than saying Judo, more people know what wrestling is and Judo is a type of wrestling anyway.
In order to remain I calm you have to be able to resign yourself to fighting if necessary. At least that is what works for me.