What Is General Adaptation Syndrome (GAS) General Adaptation Syndrome is a theory formulated in 1936 by Dr. Hans Seyle, a celebrated figure in the field of stress research. Gas depicts the process of prolonged exposure to stress by separating behaviors into 3 stages. The Alarm Reaction, Resistance and Exhaustion Stage. This behavioral model is such a valuable tool in the study of stress research because it explains both the physiological and psychological effects of stress on the human body. All Stress is caused by external stimuli; the immediate response to these challenges or threats is the