Review of the Stress Response

The stress response is a generalized or systemic response to a change (stressor), internal or external, and may be modified in specific situations. The role of stress in disease became more firmly established in the 20th century, when Hans Selye, in 1946, defined his general adaptation syndrome (GAS), or “fight or flight” concept. His work revealed that the body constantly responds to minor changes in its needs or environment, such as altered food intake or activity level, and thus maintains homeostasis. The body has built-in mechanisms that quickly compensate for physiologic changes in fluid balance or blood pressure. Minor fluctuations in body functions are normal.

A stressor is any factor that creates a significant change in the body or environment. It may be physical or psychological or a combination of the two. A stressor may be a real or anticipated factor, or it may be a short-term or long-term factor. Possible stressors include pain, exposure to cold temperatures, trauma, anxiety or fear, a new job, infection, or indeed, even a joyous occasion. Stress is considered to occur when an individual’s status is altered by his or her reaction to a stressor. The stress response is the generic but complex response made by the body to any stressor. The body’s physiologic response to different types of stressors is the same, although the response may vary in intensity and effects in a given situation or person. An additional, specific response may occur with certain stressors; for example, infection may initiate a fever.

Each person may perceive stressors differently. A certain stressor for one individual may be mildly exciting or stimulating, but for someone else the same stressor may be deeply depressing. It may even cause illness in another person. If the individual can cope with the stressor, the body returns to its normal status, but if the person cannot adapt, harmful effects may result from the stress. This may be termed “distress.”

Stressors are a normal component of life and can be a positive influence on the body when appropriate coping mechanisms function well. Stressors may stimulate growth and development in many ways. Without any changes or stressors in life, a person would merely exist in a dull, inert, unresponsive form. But if a stressor is extremely severe or is perceived as a very negative influence, or when multiple factors effect change at one time, the body’s adaptive mechanisms may not suffice. Then the body systems become more disrupted, maladaptive or inappropriate behavior can occur, and homeostasis is not possible for that person. Factors such as aging or pathologic disorders may interfere with an individual’s ability to respond adequately to a stressor. A vicious cycle may develop when the original stressor remains, and the effects of this stressor prevent the body from coping with new stressors. In some cases, more damage results, adding to the stress and lessening the person’s coping capabilities even further, thereby decreasing the probability of a return to normal status. In the same way, maladaptive behaviors such as ignoring the stressor or eating unwisely are likely to add additional problems without removing the original stressful factor.