If the stress response is persistent, over time it could mean trouble.
When you feel stress, your sympathetic nervous system kicks-in, orchestrating your body's response. Every organ, blood vessel, sweat gland, and even the tiny follicles in your skin that make your hair stand on end are affected. The adrenalin speeds up your heart rate and intensity of contractions. It diverts blood from organs that are non-essential during emergencies, and redirects it to the brain for thinking and to muscles for movement. Your breathing rate increases to keep up with oxygen demand. You become alert and vigilant.
Also released is a natural steroid called cortisol. Cortisol is amazing. When facing a short term emergency, cortisol performs an intricately-balanced, controlled shutdown of many non-essential body systems that would tax our resources.
There's also a dark downside to this wonder steroid. Our bodies are wonderfully adapted to short term stressors. But for each minute that a stressor such as anxiety persists past the time it is needed, cortisol keeps suppressing the body systems that digest, store energy, and grow/repair/replenish cells in major organs.
As long as anxiety persists and our sympathetic nervous system is activated, cortisol will be released. While it won't kill us outright, it will gradually cripple our defenses, and cause our body systems to become vulnerable to disease and infection, a little bit at a time. For those of us who are already dealing with medical conditions besides anxiety, the effect is much worse. Let's take a look at how this happens:
 It takes a significant amount of energy to create this response. If the demand 'switch' can't be shut off because of our persistent anxiety, there's no time or resources left to store energy, so a deficit occurs. Ever feel really tired after long periods of anxiety? Now you know why.
 The stess response requires oxygen and nutrient-rich blood to reach all necessary areas required to respond, so the heart beats faster and harder. Blood vessels tighten to increase blood pressure. This ensures blood gets where it is needed -- muscles for escape and brain for thinking. Speaking of blood vessels, you know how they branch into smaller and smaller vessels? The branch itself is a point of resistance, bearing the brunt of the increased pressure of blood slamming into them. Do this often enough and the wear and tear over time causes damage to the vessel wall, which the body is obligated to repair. The repair isn't quite as good as the original vessel wall, and may cause plaque to form which thickens the vessel. The repaired area tends to get damaged again and again under all that pressure, so the damage/repair cycle causes a great deal of thickening. Remember, this is happening all over your body. Sometimes these thickened plaques break off under the pressure and join up with sticky platelets, traveling around the system until it hits an area that's too thick or small for it to pass. Blood flow is reduced or stopped altogether by this clot. Whatever is on the other side of that clot needs oxygen and nutrients from blood to survive. But if the blood is blocked, the downstream cells die. Those cells could be leg muscle cells, pancreas cells, eye cells, nerve cells, lung cells, heart cells, brain cells, etc. If the cells happen to be those that carry heartbeat signals, their death can cause the beat to become irregular.
 The body stops breaking stomach contents down into components and absorbing them as they slowly wind their way thru the intestine. Instead, it diverts resources away from the digestive tract, and aims them at sources that are more readily available. Once all the fuel available in blood (glucose) is used up for example, the liver dumps glycogen into the system to replace it. After that dries up, the body goes after stored energy in the form of fat (triglycerides stored in fat cells) and protein (muscles and organs). But there's also a problem. Cortisol reduces the amount of insulin. Insulin is the 'key' that 'unlocks' the cell so it can take up nutrients for energy or storage. Cortisol also tells these needy cells not to let insulin's 'key' into the cell's 'lock'. Do this enough and some cells will starve. Not only that, but cells that live can become less sensitive to insulin's 'key', eventually leading to impaired glucose tolerance (IGT) and type 2 diabetes.
 The body shuts down acid secretion in the stomach because it is a non-essential system. Everybody thinks stomach acid increases during stress because of the pain, but here's what really happens: The stomach stops producing stomach lining, mucus and other protective substances because generating them is also non-essential. If this happens for an extended time, the lining isn't as protective as it used to be. So on days when anxiety is low, normal stomach acid comes pouring into that thin stomach lining to do its digestion thing. Only now that thin lining may not be able to withstand even normal amounts of acid, so irritation - and perhaps even an ulcer -- may eventually emerge.
There's more, but I don't want to overwhelm you. Suffice it to say: Controlling the stress response, in any safe way that works, is absolutely essential to prevent longterm consequences.
I've lived w/panic disorder for 35 years in which symptoms were poorly controlled for the first 20 years. Eventually the pile-up of consequences took me out. I couldn't work. I could barely think. My memory became spotty. I became housebound and completely disabled. It took from 2004 to 2007 to heal enough so that I could work part time. I didn't find fulltime work until 2009 and it's still much less responsibility than I had in prior years because my brain and body do not function like they used to.
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