STRESS-RELATED ILLNESS
Healthy Versus Pathologic Stress
A distinction needs to be made between “healthy” and “pathologic”
responses to stress. Everyday interaction of animals with
their environments inevitably exposes them to a variety of stress
stimuli. Indeed, to develop properly animals require such exposure
on a continuing basis. The stress system must have evolved to help
individuals respond appropriately and effectively to a variety of
threatening environmental challenges, including actual attack.
Among the many behavioral and physiological responses to such
situations is rapid activation of the SAS and the HPA axis, giving
rise to behavioral and physiological responses calculated to help
the organism survive under emergent conditions. The early response
to acute stress is protective, enhancing immune function,
promoting memory of dangerous events, increasing blood pressure
and heart rate to meet the physical and behavioral demands of fight
or flight, and making fuel more readily available to sustain intensified
activity. At the same time, overactivity of the stress system
contributes to the chronic wear and tear that render the organism
more vulnerable to disability and illness.20 Observations of the
behavior of animals in their natural habitats have shown that the
stress system was designed to deal with circumstances requiring
an immediate response to a physically threatening situation of
limited duration. Nature did not anticipate situations in which the
stress system would be activated for prolonged periods by stimuli
such as an ominous letter from the Internal Revenue Service, a
bitterly contested divorce, the perceived obligation to care for an
obstreperous spouse with Alzheimer’s disease, or a sudden financial
reverse. Nor could nature have foreseen that the development
of the man’s unique brain would also render its possessor vulnerable
to imagination-generated stress.