title: Modulating exercise-induced hormesis: Does less equal more?
abstract: Hormesis encompasses the notion that low levels of stress stimulate or upregulate existing cellular and molecular pathways that improve the capacity of cells and organisms to withstand greater stress. This notion underlies much of what we know about how exercise conditions the body and induces long-term adaptations. During exercise, the body is exposed to various forms of stress, including thermal, metabolic, hypoxic, oxidative, and mechanical stress. These stressors activate biochemical messengers, which in turn activate various signaling pathways that regulate gene expression and adaptive responses. Historically, antioxidant supplements, nonsteroidal anti-inflammatory drugs, and cryotherapy have been favored to attenuate or counteract exercise-induced oxidative stress and inflammation. However, reactive oxygen species and inflammatory mediators are key signaling molecules in muscle, and such strategies may mitigate adaptations to exercise. Conversely, withholding dietary carbohydrate and restricting muscle blood flow during exercise may augment adaptations to exercise. In this review article, we combine, integrate, and apply knowledge about the fundamental mechanisms of exercise adaptation. We also critically evaluate the rationale for using interventions that target these mechanisms under the overarching concept of hormesis. There is currently insufficient evidence to establish whether these treatments exert dose-dependent effects on muscle adaptation. However, there appears to be some dissociation between the biochemical/molecular effects and functional/performance outcomes of some of these treatments. Although several of these treatments influence common kinases, transcription factors, and proteins, it remains to be determined if these interventions complement or negate each other, and whether such effects are strong enough to influence adaptations to exercise.
authors.affiliation: School of Biomedical Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; Centre of Excellence for Applied Sports Science Research, Queensland Academy of Sport, Brisbane, Australia; jonathan.peake@qut.edu.au.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Peake
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand;
authors.forename: James F
authors.initials: JF
authors.lastname: Markworth
authors.affiliation: School of Exercise and Health Sciences, Centre for Exercise and Sports Science Research, Edith Cowan University, Joondalup, Australia;
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nosaka
authors.affiliation: Norwegian School of Sport Sciences, Oslo, Norway;
authors.forename: Truls
authors.initials: T
authors.lastname: Raastad
authors.affiliation: School of Exercise and Nutrition Sciences, Center for Physical Activity and Nutrition Research, Deakin University, Melbourne, Australia;
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Wadley
authors.affiliation: School of Exercise and Nutrition Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; and Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia.
authors.forename: Vernon G
authors.initials: VG
authors.lastname: Coffey
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D059165:Hormesis / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D009043:Motor Activity / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species
keywords: adaptation; preconditioning; stress