None of these responses seem at the ELI5 level. Let me try:
“Stress” is your brain thinking there is a threat and telling your body “do what you have to so you can get through *right now* and we’ll sort it out later.” So your body floods itself with chemicals that it thinks will help you overcome whatever threat the world has thrown at you – this is when people talk about “super human strength” for example.
The goal of this is to fight off a bear or out run another predator. These chemicals that get dumped into our body are highly toxic to us in the long run, but what does that matter if you die to this threat *right now*?
The issue for public health is that your brain is setup for living in the wild and doesn’t know that an unexpected meeting with your boss is not a threat to your life. So now we have a situation where we are constantly dumping toxic chemicals into our bodies for prolonged periods which causes all the problems you mentioned.
Stress *is* physical.
Oh sure it can have a psychological cause, and colloquially those might be what the word is used for, but what it actually is is a heightened state of activation of the sympathetic nervous system, the body’s fight or flight response.
High blood pressure is an intended feature of the sympathetic nervous system. It helps get blood to your muscles if you’re trying to outrun a lion.
Maintaining high blood pressure for months or years in a row isn’t great for your heart.
All the blood vessels going to your digestive system get partially shut off since really if you’re running away from a lion you don’t have time to worry about digestion right now. Do *that* for too long and your stomach lining might not be able to rebuild itself as fast as your stomach acid is dissolving it.
When you experience stress, your body will respond by preparing for danger, it is designed to do so. It is a great system for when you think a lion may be near.
Increased cortisol heigtens your alertness, adrenaline increases heartrate. You are ready for fight or flight. You’re basically a racecar in the red. Like racecars, your body is not designed to be in the red all the time. Stuff starts breaking down after a while.
Sorry, I need to ask to clarify and put in simpler terms of what people are saying:
So the “stress” or pain in my chest area is not just me imagining it, but a physical reaction? (I don’t have high blood pressure and heart diseases, yet.)
Ex. When I feel hurt emotionally/breakup, my heart hurts literally.
Ex. When I procrastinate and can’t focus on finishing schoolwork, I feel a clenching feeling in my chest.
It’s kind of an evolutionary leftover.
Your stress response is part of your fight or flight mechanism. You come under attack and your body prepares itself to fight or escape: Your heart rate picks up, you breathe harder and faster, your blood pressure increases, your blood stream is flooded with adrenaline… all the things you need to make you more alert, more resistant to pain, able to fight harder or run faster.
The problem is our fight or flight response evolved to deal with physical threats like predators. Short term crises. As cavemen we were born, we hunted and foraged for food, we reproduced and died. Our stress response was perfectly suited to that sort of lifestyle.
Today, most of our stress comes from non-physical factors, things that last way longer than it takes to stick a spear into a wolf or run like hell from a lion… and our stress response can’t tell the difference between being physically threatened and getting an unexpected bill we can’t pay, or worry about losing our job because we heard our company is downsizing.
Basically, think of your body’s stress response as gunning a car’s engine and hitting the NOS. It gives a massive increase in performance, but the engine isn’t designed to take that amount of stress for long periods of time