The word stress is a Latin derivative which has existed in the English language for centuries. Originally, it denoted hardship or adversity. Later, stress was used to denote a “force, pressure, strain or strong effort” applied to an object or person including his “organs or mental powers” (Hinkle, 1974b; Onions, 1933). In the biological sciences, the term stress has a connotative rather than a denotative function, suggesting, on the one hand, external stimulus characteristics which tend to upset the “milieu interieur” of the organism and, on the other, characteristics of the organism’s response to such stimulus characteristics. Stressful stimuli include mechanical and chemical trauma, toxins, bacterial and viral pathogens, loud noises, monotonous work, and threats to or changes in social relationships. The general adaptation syndrome exemplifies organismic responses which qualify as stress (Selye, 1946, 1976). This syndrome refers to a sequence of nonspecific bodily reactions which occur in response to generalized noxious stimuli. The development of the syndrome depends on the functional integrity of the pituitary and adrenal glands and is characterized by the secretion of adrenalin, noroadrenalin, and adrenocortical hormones.