Anything in the environment that leads to activation of the stress response is termed a stressor. Your view of the environment and how you interact with it will determine whether or not the object or event becomes a stressor for you. However, there are some physical stressors that are clearly life-threatening and we would all see them as such. We see that we are in danger with little time to plan our action, so our alarm response is quickly summoned. Most of us also treat novel and unusual situations as stressors, since we have no past experience in dealing with them. For these and other stressors, the amount and type of stress experienced and the activity level of the stress response depends on how we perceive the nature of the demand or threat. Flow important is it to us, how long does it last, how often does it occur and how clear are we about what is happening? To illustrate the nature of the demands we can use the example of being held up in heavy traffic. This considers the â˜on your marks’ part of the stress response sequence described on page 36.