The term ‹“stress response’ describes a series of different and complex responses made by the body to any demand it faces. The stress response is always active to some degree, operating within the normal zone of the stress balance to enable us to deal with everyday changes in the environment. When unusual, novel or excessive demands, challenges or threats arise, the stress response ensures that the body is always in a state of readiness to deal with them. Because demands can be life-threatening, physical, emotional, pleasant or unpleasant, the body’s response must be appropriate for dealing with the type of situation faced. It would not be effective and economical for the body to activate a single fixed stress response to deal with all eventualities, so different parts and levels of the stress response are activated to enable us to respond in the most appropriate way.
Dealing with life-threatening situations
If we are suddenly confronted by an actual life-threatening situation such as a car hurtling out of control towards us or someone about to attack us, our response must be immediate. The body goes on an emergency full alert and prepares for physical activity. Because of the speed and urgency of this level of response it has been called the alarm reaction and also the emergency response. It may be that running away from danger will preserve our life or it could be that staying to fight will be more effective. We decide in a fraction of a second which course of action to take.
The alarm reaction evolved to prepare our ancestors for action when confronted by a wild animal or similar threat. A split-second decision had to be made on whether to stand their ground and fight or turn tail and flee as fast as possible. So another name for the alarm reaction is the fight or flight response.