Stress is a state of mental or emotional strain or tension resulting from adverse or demanding circumstances. Stress isn't always necessarily bad. The purpose of stress is to prepare your body to take on a potentially dangerous situation that you need to react quickly to, to survive. Your hypothalamus alerts your body to the danger. A combination of nerve and hormonal signals prompts adrenal glands to release adrenaline and cortisol. Adrenaline increases heart rate, elevates blood pressure, pumping blood to major muscles, and boosts energy supplies quickly. While that is happening cortisol eliminates functions nonessential and that aren't assisting fight or flight. Some of those functions include peripheral vision and hearing. It also alters immune system responses and suppresses the digestive system, reproductive system, and growth processes. Unfortunately sometimes we perceive events that aren't actually dangerous in a threatened way and become unnecessarily stressed. If this constantly happens over a long period of time then these hormones will always be present and continue to stunt those other processes causing health problems in the future. A little stress can save your life while a lot of stress can cause major problems.