Stress (roughly the opposite of relaxation) is a medical term for a wide range of strong external stimuli, both physiological and psychological, which can cause a physiological response called the general adaptation syndrome, first described in 1936 by Hans Selye in the journal Nature.
Selye was able to separate the physical effects of stress from other physical symptoms suffered by patients through his research. He observed that patients suffered physical effects not caused directly by their disease or by their medical condition.
Selye described the general adaptation syndrome as having three stages:
* alarm reaction, where the body detects the external stimulus
* adaptation, where the body engages defensive countermeasures against the stressor
* exhaustion, where the body begins to run out of defenses
Stress includes eustress ("positive stress") and distress ("negative stress"), roughly meaning challenge and overload. Both types may be the result of negative or positive events. If one's dog dies and he/she wins the lottery, one does not cancel the other both are stressful events. Eustress is essential to life, like exercise to a muscle, but distress can cause disease. (Note that what causes distress for one person may cause eustress for another, depending upon each individual's life perception.) When the word stress is used alone, typically it is referring to distress.
Stress can directly and indirectly contribute to general or specific disorders of body and mind. Stress can have a major impact on the physical functioning of the human body. Such stress raises the level of adrenaline and corticosterone in the body, which in turn increases the heart-rate, respiration, blood-pressure and puts more physical stress on bodily organs. Long-term stress can be a contributing factor in heart disease, high blood pressure, stroke and other illnesses.
The Japanese phenomenon of karoshi, or death from overwork, is believed to be due to heart attack and stroke caused by high levels of stress.
The link between emotions and physical health is further supported by this paragraph from James A. Duke's The Green Pharmacy Herbal Handbook about the research of Dean Ornish, M.D.:
Dr. Ornish tells about a group of rabbits that added an unexpected tidbit to the research on heart disease. Kept in a laboratory under research conditions, the rabbits were genetically similar, and all received the same food and got the same amount of exercise, yet one group had 60 percent fewer heart attacks than the others. What was the difference? It turned out that the healthier rabbits were the ones kept in the lower cages, and the short person who fed the rabbits could reach the lower animals and pet them when feeding them. Love, it seems, is a life preserver.
Any factor that causes stress is called stressor. There are two kinds of stressors: processive stressors and systemic stressors.
Processive stressors are elements in the environment perceived by the organism as potential dangers. These do not cause damage directly, but are processed in the cerebral cortex. The processed information is then send via the limbic system in the hypothalamus, where they activate the supreme centers of the autonomic system. This results in the fight-or-flight (or sympathetico-adrenal) response.
Systemic stressors cause a disturbance in the organism's homeostasis and the tissue necrosis, hypotension or hypoxia.
Often both types of stressors occur simultaneously. They are usually accompanied by pain and/or intensive emotions.
Coping with stress
A given situation causes eustress in one person and distress in the other. This is so because of physiological differences, and because everyone has learned different ways to react and adapt to stress. Currently, many seminars are available for people (especially managers) to develop better habits of stress management.
Other approaches may be The Alexander Technique, meditation, T'ai Chi Ch'uan, and yoga. E.g., when Selye reviewed the physiological changes measured in practitioners of transcendental meditation, he concluded that they were the opposites of the body's reaction to stress, and that the therapeutic effect was clearest in conditions caused by a wrong way to adapt and react to stress in daily life.
Finally, serenity is a disposition free or mostly free from the effects of stress, and in some cultures it is considered a state which may be cultivated by various forms of training.
Neurochemistry and physiology
The general neurochemistry of the general adaptation syndrome is now believed to be well understood, although much remains to be discovered about how this system interacts with others in the brain and elsewhere in the body.
The body reacts to stress first by releasing catecholamine hormones, epinephrine and norepinephrine, and glucocorticoid hormones, cortisol and cortisone.
The hypothalamic-pituitary-adrenal (HPA) axis is a major part of the neuroendocrine system, involving the interactions of the hypothalamus, the pituitary gland and the adrenal glands. The HPA 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.
Folklore of stress
About the time of Selye's work, the gradual realization dawned that age-old if sometimes ill-defined concepts such as worry/anxiety, conflict, tiredness, frustration, distress, overwork, pre-menstrual tension, over-focusing, confusion, mourning and fear could all come together in a general broadening of the meaning of the term stress. The popular use of the term in modern folklore expanded rapidly, spawning an industry of self-help, personal counselling, and sometimes quackery.
The use of the term stress in serious recognized cases such as those of post-traumatic stress disorder and psychosomatic illness has scarcely helped clear analysis of the generalized 'stress' phenomenon. Nonetheless, some varieties of stress from negative life events, or distress, and from positive life events, or eustress, can clearly have a serious physical impact distinct from the troubles of what psychotherapists call "the worried well".
The information above is not intended
for and should not be used as a substitute for the diagnosis and/or treatment
by a licensed, qualified, health-care professional. This article is licensed
under the GNU Free Documentation
License. It incorporates material originating from the Wikipedia article
2012 Anxiety Zone - Anxiety Disorders
Forum. All Rights Reserved.