After reading your symptoms, I don't think you have fear, rather stress. I have this stress only in big games or tournaments. I also get this kind of stress when a project deadline is coming up.
Stress has its upside and its downsides. The upside is the ability to hyper-focus on the task. The downside is if you don't manage it, your health may be worst off in the long term.
"I have been wondering if it is very dangerous for your health as I might one day have a stroke playing chess)). Would be not exactly the way I would like to go ))) And I do have somewhat elevated blood pressure. Anyway, wanted to share and was wondering if I am not alone in this fear."
Elevated blood pressure allows you to be hyper-focused.
"I think the human body is designed for stressful moments, it has the ability to process stress-induced hormones" however everyone is different. So check with your doctor about if your body can handle stress and how much. If you choose to continue to play, your doctor can provide a stress management plan.
To sum up:
I'm no health professional so consult them about your personal case. I get the stress too and I manage it.
I love chess. I played it since 7 years old. And I was progressing fast, even played against Karpov once (in simultaneous, of course) holding on for 45 moves, which I was very proud of! And then, when I was around 13, I just stopped, as I couldn't overcome my fear of playing anymore! I am now 50+, and I started playing online games again, thanks to chess.com and coronavirus. I still have the fear, which I constantly fight when play. Many of you won't understand it, it is not fear of loosing my rating or such. It happens even when I play fully anonymous chess here. No consequences! It is completely irrational fear! Yes, I know. Those who say that just playing more would cure it don't understand what they are talking about. Everybody has some fear of something. Some people, for example, are afraid of snakes or spiders. I mean non-venomous ones. If you are one of those people (by the way, I am completely not), telling you, comm'n, they are not gonna kill you, won't help at all. You're still afraid. Another example, for those of you who are afraid talking and meeting girls, can you just calm yourself down and say, like, hey, they not gonna bite me, etc. Would it help you to be not afraid of talking to a completely strange girl? I doubt it. You will still be terrified talking to them regardless.(By the way I have always been good with meeting girls, no problem))) This is the fear I am talking about. It is deeply subconscious fear. And cannot be dealt with reasoning. Anyway, I still play. And my concern is for my health. When I start, my brain switches to a full combat mode. It thinks that it is a real fight, so I experience adrenaline rush, 120-140 heart rate, tunnel vision, exactly the things I have experienced when got involved in numerous real physical fights especially when was younger. It is great for physical fight, but, obviously, not for chess, as it affects the thought process. I have been wondering if it is very dangerous for your health as I might one day have a stroke playing chess)). Would be not exactly the way I would like to go ))) And I do have somewhat elevated blood pressure. Anyway, wanted to share and was wondering if I am not alone in this fear. And maybe someone with similar experiences could suggest some mitigation techniques (beyond usual, hey, what are you afraid of? No consequence! ) Cheers!