The field of health psychology investigates the relationship between
psychological, behavioral, and social processes and physical health. A goal of
health psychologists is to apply their research to prevent illness and promote
Stress is the negative physical and psychological adjustment to circumstances that
disrupt, or threaten to disrupt, a person's functioning. Stress always involves a
relationship between people (stress reactions) and their environments (stressors
Mediating factors affect the severity of stress reactions. Examples of mediating
factors include perceived control over stressors, available social support, and
quality of stress-coping skills.
Both pleasant and unpleasant events or situations can cause stress.
Catastrophic events that are life-threatening, such as assault, combat, fire,
and tornadoes, can lead to serious psychological disorders. Life changes
and strains can be stressors, especially if they force a person to adapt.
Examples of such changes include divorce, marriage, bad grades,
graduation, a new job, a promotion, and death. Daily hassles, such as
minor irritations, pressures, and annoyances, when experienced regularly,
can act as stressors.
Several ways of measuring stress have been developed based on the
premise that stress is a process that requires a person to make some sort of
life adjustment. One instrument, called the Social Readjustment Rating
Scale, measures stress in terms of life-change units (LCUs). Research
suggests that people who experience a greater number of LCUs are more
likely to suffer physical and mental illness. The Life Experiences Survey
(LES), another instrument for measuring stress, also considers an
individual's perceptions of the positive or negative impact of a given
stressor. By examining perceptions of stress, the LES is able to measure
the role that gender and cultural differences play in experiences of stress.
The General Adaptation Syndrome. The general adaptation
is a stress response composed of three stages.
Stage 1. The fight-or-flight syndrome (FFS), or alarm
reaction, is the first stage. The sequence of events causing
the FFS is controlled by the sympatho-adreno-medullary
system (SAM); the hypothalamus triggers the sympathetic
ANS, which stimulates the adrenal medulla, which in turn
secretes catecholamines into the bloodstream.
Catecholamines stimulate the heart, liver, kidneys, and