General Adaptation Syndrome (GAS) is a theory developed by endocrinologist Hans Selye to explain how the human body responds to stress over time. It describes the physiological and psychological changes that occur when an individual encounters a stressful situation. According to Selye, stress is a non-specific response of the body to any demand placed upon it. The theory is widely used in stress management because it helps individuals and organizations understand how prolonged exposure to stress affects health, performance, productivity, and well-being. Knowledge of GAS enables people to recognize stress symptoms early and adopt appropriate coping strategies before stress becomes harmful. The General Adaptation Syndrome consists of three distinct stages: the Alarm Reaction Stage, the Resistance Stage, and the Exhaustion Stage. The Alarm Reaction Stage is the body's immediate response to a stressor. When a person faces a threat or challenge, the brain signals the release of stress hormones such as adrenaline and cortisol. This activates the "fight or flight" response. Physiological changes include increased heart rate, rapid breathing, elevated blood pressure, muscle tension, and heightened alertness. These changes prepare the body to deal with the stressful situation. For example, an employee facing an unexpected presentation may experience