ADAPTATION TO STRESS

Types of stress :

o Eustress

Where stress enhances function ( physical or mental, such as through strength training or challenging work ) it may be considered eustress.

o Distress

Persistent stress that is not resolved through coping or adaptation may lead to escape ( anxiety ) or withdrawal ( depression ) behavior.

Responses to stress include :

o Adaptation

Three stages of general adaption syndrome ( GAS ) :

Stage one: alarm

When the threat or stressor is identified or realised, the body's stress response is a state of alarm. During this stage adrenaline will be produced in order to bring about the fight-or-flight response. There is also some activation of the HPA axis, producing cortisol.

Stage two: resistance

If the stressor persists, it becomes necessary to attempt some means of coping with the stress. Although the body begins to try to adapt to the strains or demands of the environment, the body cannot keep this up indefinitely, so its resources are gradually depleted.

Stage three: exhaustion

In the final stage in the GAS model, all the body's resources are eventually depleted and the body is unable to maintain normal function. At this point the initial autonomic nervous system symptoms may reappear ( sweating, raised heart rate etc ). If stage three is extended, long term damage may result as the capacity of glands, especially the adrenal gland, and the immune system is exhausted and function is impaired resulting in decompensation. The result can manifest itself in obvious illnesses such as ulcers, depression or even cardiovascular problems, along with other mental issues.

o Psychological coping such as :

Anxiety

Stress management

Depression

Both negative and positive stressors can lead to stress. Some common categories and examples of stressors include :

o Sensory : pain, bright light

o Life events : birth and deaths, marriage, and divorce

o Responsibilities : lack of money, unemployment

o Work/study : exams, project deadlines, and group projects

o Personal relationships : conflict, deception

o Lifestyle : heavy drinking, insufficient sleep

o Early life exposure (e.g. child abuse) can permanently alter an individual's stress response

o Environmental : Lack of control over environmental circumstances, such as food, housing, health, freedom, or mobility

o Social: Struggles with conspecific individuals and social defeat can be potent sources of chronic stresses

The body reacts to stress first by releasing the hormones such as :

1. Catecholamine

2. Epinephrine

3. Norepinephrine

4. Glucocorticoid

5. Cortisol

6. Cortisone

Stress activates the sympathetic branch of the autonomous nervous system and produces the fight-or-flight response, causing the body to divert bloodflow to large muscles as the body prepares to run away from or fight something. Less blood flows to the digestive system and other organs that do not assist in fleeing or fighting, producing dry mouth, motor agitation, sweating, pallor, enlarged pupils and over the long term, insomnia. Modern stressors can cause continual sympathetic nervous system activation with very little opportunity for the parasympathetic nervous system to activate. When the parasympathetic system is active, the bowel and other non-muscle organs receive good blood-flow, the pupils constrict, and the glands all function well and secrete their various compounds. Absence of the autonomic parasympathetic activation leads to poor digestion and may lead to poor healing and organ function.

The hypothalamic pituitary adrenal ( a major part of the neuroendocrine system, involving the interactions of the hypothalamus, the pituitary gland and the adrenal glands ) axis is believed to play a primary role in the body's reactions to stress by balancing hormone releases from the adrenaline-producing adrenal medulla, and from the corticosteroid-producing adrenal cortex. Stress can significantly affect many of the body's immune systems, as can an individual's perceptions of, and reactions to, stress. The term psychoneuroimmunology is used to describe the interactions between the mental state, nervous and immune systems, as well as research on the interconnections of these systems.