Wikipedia Encyclopedia for its part tells us, that stress, (in English, stress), fatigue, is a physiological reaction of the organism in which come into play various mechanisms of Defense to face a situation that is perceived as threatening or increased demand. Stress is a natural and necessary response for survival despite which, nowadays, is mistaken for a pathology. This confusion is due to that this defense mechanism can finish, under certain circumstances that abound in certain modes of life, triggering serious health problems. It is an emerging labor pathology that has a special impact on the sector services. Still the greatest risk in tasks that require greater demands and dedication.

Background medspain.com has written, that the concept stress goes back to the 1930s, when a young Austrian man of 20 years old, second year student of medicine at the University of Prague, Hans Selye, son of the Austrian surgeon Hugo Selye, noted that all the sick people who studied, regardless of the disease itself, showed overall and common symptoms: tiredness, loss of appetitelow weight, asthenia, etc. This drew much attention to Selye, who called it the syndrome of being sick. Hans Selye, graduated as a doctor and later a Ph.d. in Chemistry organic at your University through a scholarship from the Rockefeller Foundation moved to Johns Hopkins University in Baltimore EE.UU. to perform a post-doctorate whose second half made in Montreal Canada in the school of Medicine of McGill University, where he developed his famous experiments of strenuous physical exercise with laboratory rats which found the elevation of adrenal hormones (ACTH, adrenalin and) noradrenaline), the atrophy of the lymphatic system and the presence of gastric ulcers. The set of these organic disorders Dr. Selye called biological stress.

Selye was considered then that several unknown as the heart diseases, high blood pressure and emotional or mental disorders were not but the resulting from physiological changes resulting from a prolonged stress in the above-mentioned shock bodies and that these alterations could be default genetic or constitutionally. However, to continue with his investigations, he joined to his ideas, that harmful physical agents acting directly on the animal organism are not only producing stress, but in addition, in the case of man, the demands of a social nature and threats to the environment of the individual requiring adaptability cause the stress disorder. In ancient times the stress mechanism fulfilled the purpose of preparing the human beings to respond to States of emergency that you they represented a physical threat. How to respond to this kind of emergency was, generally speaking, fleeing or fighting, answers to which requires a lot of energy and muscle strength. Hormonal changes and other physiological changes that occur in States of stress are aimed to achieve this. In our modern society we must not confront usually wild animals (at least in the literal sense of the term). However, we are facing situations of other types such as problems at work, or marriage, with the same mechanisms with which our ancestors faced by wild animals.