According to Ader, the response to a stressful challenge involves many different interactions among the nervous, endocrine, and immune systems (Ader). During a stressful event, the body may undergo a series of biological and chemical changes. For example, the sympathetic nervous system and hypothalamic pituitary adrenal axis system are activated and hormones are released (lecture). This promotes the process of turning fats into energy for the body to use and therefore, this energy, which could be used in other systems and activities in the body, is not available (lecture). When the body becomes stressed a new pattern of energy distribution occurs, where most of the energy is being used by the skeletal and brain muscles in response to the fight
