Stress and the neuroendocrine system: the role of exercise as a stressor and modifier of stress

Abstract

In this article, the physiological impact of one form of stress -physical exercise -on the neuroendocrine system will be discussed. The specific intent of the review is to present an overview of stress endocrinology, the conceptual models associated with this area of study, and a discourse on the dual role of exercise as both a stressor and a modifier of stress within the neuroendocrine system. These points are addressed with respect to the current research literature dealing with exercise endocrinology in an adult population. Keywords disregulation; endocrinology; hormones; physical activity; sport Stress is something experienced by all of us, no matter who we are, and it has both a positive and a negative effect on our lives. Modern society has created an environment where there are tremendous opportunities to experience both negative stresses (distress) as well as positive stress (eustress) on a daily basis [1,2]. Such stressful encounters have profound impacts upon the physiological workings of the human body, both in constructive and destructive fashions. One physiological system that is extremely reactive to stress is the neuroendocrine system [1,2]. In fact, many clinicians and researchers use the responses of the neuroendocrine system as a means of assessing the stress effects and reactivity of the human body.Physical exercise is an activity that is known to provoke large and diverse stress responses within the neuroendocrine system. However, chronic exercise training is also known to cause abatement in the stress responses of the neuroendocrine system to certain forms of stress. The intent of this article is to provide an overview on these somewhat paradoxical effects of physical exercise upon the neuroendocrine system. Specifically, the intended purpose of this review is twofold: to provide a brief overview of stress endocrinology and the conceptual models associated with this area of study; and to address the dual role of exercise as both a stressor and a modifier of stress within the neuroendocrine system, both in acute and chronic exposure settings.

Research Methodology: Endocrinologic Measurements in Exercise Science and Sports Medicine

“…Certain mental health conditions are associated with high anxiety levels (eg, posttraumatic stress disorder), which can lead to enhanced sympathetic nervous system and hypothalamic-pituitary-adrenal axis activity. [34][35][36] Subsequently, resting levels of circulating catecholamines, adrenocorticotropic hormone, b-endorphin, and cortisol also may be elevated in these conditions. In contrast, persons who are depressed may have low arousal levels and suppressed levels of the aforementioned hormones.…”

Regular swimming before the induction of ulcer ameliorates oxidative gastric damage in rats: The anxiolytic effect of exercise

“…Physical exercise, as a powerful stressor with physical, psychological, and physiological effects, is proposed to have a modifying role on the circulating levels of cortisol [44,45]. Studies have shown that moderate to high intensity exercise increases circulating levels of cortisol, while low intensity exercise may even result in reduced cortisol levels [46].…”

The effect of long term physical exercises on plasma cortisol levels

“…Upon released into the blood, cortisol acts on a variety of peripheral tissues, such as skeletal muscle, adipose tissue, and the liver. In the adipose tissues, it induces the hydrolysis of triglycerides into free fatty acids and glycerol (Hackney, 2006, McMurray & Hackney, 2000, Viru & Viru, 2004. It has been found that cortisol increases glycogen breakdown in the liver (Kalamidas & Kotoulas, 2000).…”