Consider a block that is resting in between two springs (there is a dampener for those that care, so just go with it). The compressed side will push back if the block is pushed to either side, whereas the stretched side will pull back into the resting position. Once set free, they will oscillate until they are at rest again. However, the springs will ultimately alter and their resting position will alter if you consistently lean to one side.
The parasympathetic nervous system slows you down, absorbs and stores resources, repairs damage, and resists environmental demands for change. It is one of your two autonomic nervous system springs. You move faster thanks to the sympathetic system, which also releases energy and resources in response to environmental demands for change.
Your brain rapidly causes the adrenalin glands to release epinephrine and norepinephrine, which boost the sympathetic nervous system, when a threat or stressor is present. Your SS outweighs the PS, just like the springs. You actually go through the fight-or-flight reaction. Elevated heart rate, blood pressure, respiratory rate, glycogen breakdown, and changes in blood and air flow all work to get the body and brain ready to work at their best. Your senses become more acute, your eyes enlarge to improve your ability to see in the dark and detect movement, and the only exocrine process that is unaffected is perspiration. Acute stress causes this type of stress response, which reduces appetite.
Your systems must work very hard in this state, though. It gives you the motivation to either remove the threat or flee from it in a life-or-death emergency. Your springs will rebound once the threat has passed. As your PS pushes past the balance, there is a "lashback" of fatigue and sleepiness. Your body then attempts to return to homeostasis. You experience your post-workout munchies at this time.
However, the fight or flight response slows down to prolong the heightened wakefulness in cases of persistent stress. The stress reaction also includes the release of corticosteroids. These hormones enable you to respond in brief stressful situations. They flood the circulation with enormous amounts of glucose and fatty acids. However, these stress hormones accumulate and persist in chronic stress. This causes a rise in appetite and a yearning for salt, sugar, and fats. components that stress depletes but are crucial.
The balance becomes dysfunctional in this situation. Individual balances are out of whack, but they nonetheless exert a similar amount of effect. The psychological aspects of this imbalance frequently play a role. You may feel more hungry and be less active mentally if you are trying to escape the tension. Fighting may cause you to spend all of your energy on cerebral activities rather than other bodily processes like digestion, which will make you feel less hungry. You normally enter significant depression area if you chance to encounter the freeze response, which occurs when there is no way that you can conceive of to flee or defend yourself. Because to freeze is to completely lose all hope when one is entrapped and outnumbered.
Chronic stress causes tolerances and sensitivities, which have a tendency to reinforce one another and make it more difficult to reverse the situation. This typically makes the mental condition worse, which feeds the cycle.
Fun fact: fear can actually cause death. However, it isn't fear that kills them. The strong PS reaction is what causes your heart to stop beating. The stress of losing a life partner, sometimes known as sadness, is another reason why an elderly widow or widower will degenerate and pass away suddenly not long after the loss.