The general adaptation syndrome, which is also known as the stress response, has three stages. The syndrome begins when the body encounters a stressor, such as emotional anxiety or the threat of physical injury. In the first stage, the body prepares for action by initiating the fight or flight response. During the second stage, the body remains in a state of alert, though it attempts to normalize to the new conditions caused by the stressor. In the final stage of the general adaptation syndrome, the body becomes exhausted and ceases to fight against the stressor.
When a person is exposed to a stressor, chemical changes occur in the body that are designed to help that person successfully deal with the stressful event. The first stage in the general adaptation syndrome, which is called the alarm stage, is marked by the release of adrenaline into the blood stream. The adrenaline causes the fight or flight response, which, as its name suggests, readies a person to either run from or fight the danger. During the first stage of the general adaptation syndrome, the blood pressure rises, respiration and heartbeat increase, and non-essential systems, such as digestion, shut down. Fear and anxiety are also a part of this stage because these emotions help keep the person alert and able to focus on the immediate danger at hand.
After the alarm stage, a person goes into the second stage of the general adaptation syndrome, the resistance stage. Though many stressors can lead to death, in the event a person survives the danger, without overcoming it, that person’s body attempts to adjust to the new conditions as best it can. Extra energy is invested in the immune system, and though the person may seem relatively calm, the body is working much harder while moving through the resistance stage than it does in a state of low or no stress. The person may continue to be in a state of physical and emotional arousal, as in the alarm stage, though the level of arousal is much lower in this second stage.
Eventually, the body cannot keep up with the extra energy needed to remain in the resistance stage, and the person then moves into the third stage of the general adaptation syndrome, the exhaustion stage. At this point the body cannot keep up its state of alarm or resistance and stops fighting. If stressors continue after this stage is reached, the person may become susceptible to certain types of diseases, as the extra energy to invest in the immune system is no longer available.