How many would like to be chased by a wild animal. How about having to actually fight all of the time. Our body's fight or flight system at one time was actually really useful. If you were in a cave and there was an animal that came after you, you had to fight it or flight-run.
In today's world there are not as many real stressors like this. I'm not saying they don't exist, but in much smaller occurances. The subconscious mind and its comonents don't know this though. They treat thoughts or lighter stressors as real as the tiger running after you. This causes the adrenaline and blood flow to those parts of the body to run, to stay on.
This is how my body has ran for years. Mine it usually a scary thougth that will cause it. This is the worse, since it isn't even anything but an ability-the thought. I am smart enough to know this, but I let them get me hopped up anyway.
Life is even more stressful than even a few decades ago. You had three television stations to choose from, now you have hundreds, plus the on demand Tubi, Netflix, and Youtube. The more choices you have somethimes spells more stress. Then take the phone. Shopping for cell phone plans didn't exist a few decades ago. You only had one phone for the house, instead of multiple lines. Imagine this for all the technology we have. Lets not forget the money stress paying for all this, that we didn't have to worry about.
I am not saying to give up all of these but it has to be watched. Find a way to make the best choices and go with it. Also, make sure that you don't spend more than you can afford. I am just pointing out that our modern world brings many more stressors than it used to. You have to find the right way to combat the stress. Slowing down and meditating come to mind. Good luck in our go go world.