Stress is your body’s response to any stimulus. Any type of stress triggers physiological responses: your adrenaline output increases, your heart pumps faster, and your breathing rate goes up. These bodily responses are positive if you channel them over a short period of time, but if there is no release, however small, then stress becomes a negative force. The strain of negative stress manifests such symptoms as: chronic fatigue, headaches, a change in eating habits, inability to concentrate, general irritability, as well as other physical problems.
A certain amount of stress, however, is beneficial. An experiment conducted in 1908 by Yerkes and Dodson studied the effects of stress on learning in lab animals. Those subjected in laboratory animals. Those subjected to extreme stress or no stress learned less than those subjected to moderate levels of stress. In 1983 a similar study was performed by Bossing and Rouff using children in a classroom environment. The 1983 study confirmed the results of the earlier experiment by Yerkes and Dodson. The graph below illustrates their results.