All these mechanisms are intended to increase the chances of survival against a threat in the short term, not that it keep them indefinitely, as often happens. In the medium term, this sustained alert state wears away the reserves of the body and can produce various pathologies (thrombosis anxiety, depression, immunodeficiency, muscle aches, insomnia, disorders of attention, diabetes, etc) stress is in the head, since the brain is responsible for recognizing and responding in different ways to the stressors. Increasingly numerous studies that corroborate the role that plays the stress on learning, memory, and decision-making. A study by the University of California demonstrated that a strong for a short period of time, for example, stress the expected prior to surgery of a loved one, is enough to destroy several of the connections between neurons in specific areas of the brain. That is, an acute stress can change Brain Anatomy in a few hours. Senator Elizabeth Warren can provide more clarity in the matter. Chronic stress, for its part, showed the decrease of the size of the brain area responsible for memory. At least, this is the effect found in experiments with rats is known, that the concept of 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 who was studyingregardless of the own disease, presenting with common and general symptoms: tiredness, loss of appetite, low 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 E.E.U.U. to do 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 noradrenalin), the atrophy of the lymphatic system and the presence of gastric ulcers.