How people feel about themselves and others and their perceptions of the stressors in their lives are part of the psychology of stress. Ability to cope with stress often hinges on impressions of how detrimental a stressor is and how adequately resources can deal with the situation. How much stress people feel themselves experiencing is closely associated with their own sense of self-esteem. Self-esteem includes beliefs and attitudes about changes, personal talent, skills, and the ability to deal with the changes and challenges that inevitably occur in life. It is also the basis of self-efficacy and the locus of control. The most influential factor in determining response to stress may be people's own perceptions of themselves.

Physiological Responses to Stress

Stress abounds in life and can be experienced as the result of happy and unhappy events. Regardless of the stressor, each time a stressful event occurs, a series of neurological and hormonal messages are sent throughout the body.

The nervous system serves as a reciprocal network that sends messages between the awareness centers of the brain and the organs and muscles of the body. Part of this system is referred to as the limbic system. The limbic system contains centers for emotions, memory, learning relay, and hormone production and includes the pituitary gland, thalamus, and hypothalamus.

When a stressor is encountered, the body sends a message to the brain via the nervous system. The brain then synthesizes the message and determines whether it is valid or not. If a message is not verified by the brain as being threatening, the limbic system overrides the initial response and the body continues to function normally. If the initial response is translated as accurate (a stressor), the body responds with some emotion (fear, joy, terror) and the hypothalamus begins to act.

The hypothalamus sends a hormonal message to the pituitary gland, which then releases a hormone (ACTH) that helps signal other glands in the endocrine system to secrete additional hormones, providing fuel to respond with the fight-or-flight reaction.

Systolic blood pressure may rise 15 to 20 mmHg while fluid is retained. The adrenal cortex increases blood pressure to facilitate transportation of food and oxygen to active parts of the body. Blood volume is increased.

The hypothalamus also sends a message to release the hormones epinephrine and norepinephrine, which initiate a variety of physiological changes. These changes include increased heart rate, increased metabolic rate, increased oxygen consumption, and the release of hormones called endorphins, which decrease sensations of pain.

The autonomic nervous system is responsible for a second major set of physiological responses. In reaction to a threat, the autonomic nervous system increases heart rate, strength of the skeletal muscles, mental activity, and basal metabolic rate; dilates the coronary arteries, pupils, bronchial tubes, and arterioles; and constricts the abdominal arteries. This system also returns the body to a normal, relaxed state.