Characterization of Exercise-Induced Cytokine Release, the Impacts on the Body, the Mechanisms and Modulations

Abstract

As for the classification of cytokines [1,2], there are pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, which induce acute inflammation. Immunomodulatory cytokines such as IL-2, interferon (IFN)-γ and IL-12p70 are produced to induce cellular immunity as protection against pathogens such as viruses and intracellular bacteria. Figure 1 shows the cytokine balance based on helper T (Th) cells, and the effects of exhaustive exercise on the component cytokines are described later (Figure 1) [5]. There are also anti-inflammatory cytokines such as IL-1 receptor antagonist (IL-1ra), IL-4, IL-6, IL-10 and IL-12p40, which block action and production of other pro-inflammatory and immunomodulatory cytokines. Here, IL-6 is classified as a multi-functional cytokine, because it can act as both a pro-and an anti-inflammatory cytokine, depending on the progression of inflammation. Colony-stimulating factors are involved in hematopoiesis, mobilization and activation of neutrophils and monocytes. Chemokines are chemotactic cytokines that regulate tissue infiltration of leukocytes. This article firstly introduces findings on the effects of most exhaustive exercise conditions, a maximal intensity exercise within 30 min, and a long duration race such as marathon, duathlon and triathlon on cytokine release in observational studies. Then, some of the main experimental research concerning the impacts on the body and the underlying mechanisms of endurance exercise-related phenomena are highlighted. Besides, our findings of cytokine dynamics following eccentric exercise in relation with muscle damage were paradox-Abstract The objective of this review is to introduce significant research findings mainly on cytokine responses to exercise. First, some basic background information on cytokines is provided. Then, some of our data according to exercise modes and key experimental research on the factors affecting cytokine responses to exercise are explained. Furthermore, the mechanisms and modulations of the cytokine responses are described to understand stress and inflammatory reactions and their prevention/recovery.