The Dangers of Stress Stress acts as a relevant and integral piece of our daily lives. Defined as a stimulus that precipitates a physiological reaction in the brain, stress functions to activate a response in the body that has historically served as a survival mechanism for the human population. Stress can be caused by daily responsibilities and routines, or more traumatic events such as development of an illness or hospitalization. Sustained levels of elevated stress responses cause profound alterations in proper functionality of immune system physiology. This can potentially lead to development and propagation of various chronic illnesses, including cancer. The magnitude and duration of elevations in stress hormones affects immune cell trafficking and function, thereby affecting health outcomes. In order to further understand this concept, it is important to survey the types of immune system responses responsible for overall health and well-being. How Stress Affects the Protective Immune System First, the protective part of the immune system mechanistically functions to elicit immediate action in response to wounds, trauma, and/or infection. This involves many of the 'fight or flight' hormones – such as epinephrine, norepinephrine, and cortisol. In terms of cancer, this piece is vital for appropriate monitoring of cell...