Final answer:
Stress is a physical and emotional response to perceived threats, encompassing physiological and behavioral responses designed to promote survival. Chronic stress from psychological sources can negatively impact health. Stress is influenced by how we perceive and appraise potential threats.
Step-by-step explanation:
Stress can be defined as a physical and emotional reaction to potentially threatening aspects of the environment. This encompasses a wide variety of physiological and behavioral responses such as increased heart rate and muscle tension. These responses, also known as the fight-or-flight response, have been developed evolutionarily to enable survival by preparing the body to either flee from a threat or confront it directly. However, in modern times, stress often arises from psychological sources rather than physical dangers, and chronic or repeated exposure to stressful situations can lead to negative health consequences, including heart disease and immune system dysfunction.
An increase in susceptibility to illnesses like heart disease and a weakened immune system is often associated with the long-term activation of the body's stress response, which can result from ongoing psychological stress. This continual state of arousal is far less adaptive in the contemporary world, where the threats we face are often not ones we can physically escape or combat. The way individuals appraise events—as threatening or manageable—plays a critical role in determining their level of stress.