WHAT IS STRESS? Stress is our body's response to anything that poses a threat to our well-being. These “threats” come from our external environment and can be described as “stressors”. Stressors act as a stimulus that causes stress. The relationship between a stressor and our stress level is directly proportional, because the more stressors we are exposed to (whether it's work pressure, loud noises, or traffic), the more stressed we will feel. Depending on the type of stress we experience, our body will react in different ways and activate the “fight or flight” reflex. This reflex is the result of our body's sympathetic nervous system. [1]PHYSIOLOGICAL MECHANISM BEHIND STRESS [2]The stress response has three phases. The first is the “alarm phase,” which is your acute stress response (when you become afraid after a friend scares you). The next phase is known as the “resistance phase”. This second phase is more closely linked to chronic stress (constant pressure at work). Finally, we have the “exhaustion phase” which is the most severe phase of long-term stress exposure. 1) Alarm phase: This phase involves the sympathetic division of the autonomic nervous system. The alarm phase uses glucose as an energy reserve and incorporates the “fight or flight reflex.” The most important hormone released during this response is epinephrine. The physiological effects of this response include: • an increase in mental alertness • an increase in the amount of energy used by all cells in the body • a “mobilization of glycogen and lipid stores” [2] • a decrease in activity of the digestive system• a decrease in urine production• an increase in the amount of sweat produced by the sweat glands• an increase ...... middle of paper ......e pituitary gland. [16]8.IN CONCLUSION, we can say that stress produces hormones (notably glucocorticoids) which have a negative impact on the immune system when our body is exposed to them for a prolonged period. However, when our immune system is exposed to particular stressors for a shorter period of time, it can actually have a positive effect on our immune system and give it a "boost." Stress in general has a major effect on our cytokines, natural killer cells, and T cells, as they are most sensitive to anti-inflammatory glucocorticoids. Macrophage migratory inhibitory factor is one of the main reasons why our immune system becomes hypersensitive to any allergen, when our body produces glucocorticoids. Stress therefore has a fairly significant effect on our immune system and our body's ability to fight disease...