THE PHYSIOLOGICAL MECHANISM OF STRESS RESPONSE IN HUMAN

Abstract

In this review, we report on studies evaluating the effects of endogenous and exogenous increases in stress hormones on human cognitive performance, human stress response mechanisms to maintain homeostasis under conditions of real or perceived stress. This goal is achieved through a mechanism of autoregulation closely related to the central and peripheral clocks by the nervous and endocrine systems. The hypothalamic-pituitary-adrenal axis (HPA axis) is an important regulatory pathway in the maintenance of these homeostatic processes. Cortisol as the end product of this pathway is secreted in a dynamic pattern, with changes in pulse amplitude producing a biological pattern. During periods of acute stress, cortisol levels rise and stability is maintained. During chronic stress, hypothalamic pituitary activation changes from the predominant corticotropin-releasing hormone to arginine vasopressin, and cortisol levels are increased by decreased cortisol metabolism. Acutely elevated cortisol levels are beneficial for promoting survival in healthy individuals as part of the body's response. However, chronic exposure to stress reverses beneficial effects, with long-term exposure to cortisol possibly leading to problems including metabolic syndrome, obesity, cancer, disorders mental health, cardiovascular disease and increased susceptibility to infection. This article also discusses neuroendocrine regulation in pathological states and glucocorticoid-based therapies.