Chronic stress

Chronic stress is the physiological or psychological response induced by a long-term internal or external stressor. The stressor, either physically present or recollected, will produce the same effect and trigger a chronic stress response. There is a wide range of chronic stressors, but most entail relatively prolonged problems, conflicts and threats that people encounter on a daily basis. And several chronic stressors, including "neighbourhood environment, financial strain, interpersonal stress, work stress and caregiving.", have been identified as associated with disease and mortality.

Stress responses, such as the fight or flight response, is fundamental. The complexity of the environment means that it is constantly changing. To navigate the surroundings, we, therefore, need a system that is capable of responding to perceived threatening and harmful situations. The stress response system thus has its role as an adaptive process to restore homeostasis in the body by actively making changes. For instance, the body will involve in an endocrine system response in which corticosteroids are released. This process is known as allostasis, first proposed by Sterling and Eyer (1988). Research has provided considerable evidence to illustrate the stress response as a short-term adaptive system. The immediate effects of stress hormones are beneficial in a particular short-term situation. The system is arguably a protective defense against threats and usually does not pose a health risk.

However, the problem arises when there is a persistent threat. First-time exposure to a stressor will trigger an acute stress response in the body; however, repeated and continuous exposure causes the stressor to become chronic. McEwen and Stellar (1993) argued there is a "hidden cost of chronic stress to the body over long time periods". That is often known as allostatic load. Chronic stress can cause the allostasis system to overstimulate in response to the persistent threat. And such overstimulation can lead to an adverse impact. To illustrate, the long-term exposure to stress creates a high level of these hormones. This may lead to high blood pressure (and subsequently heart disease), damage to muscle tissue, inhibition of growth, and damage to mental health. Chronic stress also relates directly to the functionality and structure of the nervous system, thereby influencing affective and physiological responses to stress. These subsequently can result in damage to the body.