The first time we used the concept stress, was in a work published in 1936 by Hans Selye. The stress is defined as: a nonspecific response of the body to any requirement. It occurs as a reaction to a stimulus called stressor and implies a process of adaptation that is manifested by changes in hormone levels. Based on this definition, Esteve reveals the biological dimension of stress, i.e., the human being as a whole respond organically, with changes in the organism to any stressor that affects the person. Trianes, 2002, in the book stress in childhood asserts: the concept of stress involves at least four factors:-presence of a situation or identifiable event. -This event is capable of altering the physiological and psychological balance of the body. -This imbalance is reflected in a State of Activation marked by a series of consequences for a person of kind neurophysiologic, cognitive and emotional.

-These changes, in turn, disrupts the adaptation of persons. If we analyse all these definitions stress occurs in the person who responds to a stimulus, both inside and outside, as a unitary whole but that stress is not directly measured as weight or mass, but the body responds by altering its operation and this alteration causes some internal and external symptoms that define stress. Therefore, the definitions given on that concept could be grouped into three approaches: 1 stress as a stimulus. 2nd stress as 3rd response approach interactive first, is defined stress as a stimulus or environmental condition when it is dedicated to identify the different sources of pressure that affect persons and to the study of the responses physiological, cognitive, and behavioral consequences of such pressure. Example of that It would be excessive work, high responsibility in an event, etc. If deemed as response defined stress as the signs of stress, i.e., they are the answers Psychophysiological and behavioural that would define stress.