assessing, or alleviating distress. Because minimization or elimination of distress experienced by laboratory animals is not only a regulatory requirement but also a moral obligation, it is imperative to attempt an evaluation of the state of the science and to translate current scientific knowledge into practical guidelines for use in laboratory animal facilities. Specifically, the Committee was tasked with preparing

The Committee approached its task from the perspective of performance standards without describing—among others—factors such as intensity, duration, or types of perturbations, in part because this is an advisory document about an insufficiently understood phenomenon, but also because the Committee members believe that—within the current state of science—the best approach to recognize and alleviate distress is through best practices and professional judgment.

Various views, definitions, and language have been used in the discussion of stress and distress. Current scientific knowledge supports the concept that stress is a real or perceived perturbation to an organism’s physiological homeostasis or psychological well-being. In its stress response, the body uses behavioral or physiological mechanisms to counter the perturbation. Events that precipitate stress (called stressors) can elicit any of a number of coping mechanisms or adaptive changes, including behavioral reactions, activation of the sympathetic nervous system and adrenal medulla, secretion of stress hormones (e.g., glucocorticoids and prolactin), and mobilization of the immune system.