Hormesis refers to the beneficial adaptive effects resulting from cellular responses to single or multiple rounds of mild stress. The phenomenon implies that repeated exposures to a chemical insult elicit adaptive changes within the organism to resist to higher stress, with reduced harm and reduced incidence of multifactorial diseases associated with chronic low-grade inflammation (cardiovascular, metabolic, neurodegenerative diseases and cancer). Hormesis could have important implications during both military activity and exercise training of recreational, competitive, and elite athletes. Furthermore, regular exercise and sports practice (training) can also lead to veterans and non-military individuals with either motor or mental impairments to excel in some sports disciplines, giving rise to the phenomenon of the Paralympics.

Exercise-induced reactive oxygen species (ROS) production can induce hormesis-like adaptations, including up-regulation in endogenous antioxidant defenses, whereas it is debated whether antioxidant supplementation could eliminate or improve this adaptive response. It has been suggested that the effects of antioxidant treatment are dependent on the intensity of exercise because the adaptive response, which is multi pathway dependent, is strongly influenced by exercise intensity. Furthermore, whole foods, rather than nutraceutical capsules, contain antioxidants in natural ratios as well as prebiotics and seem to improve the antioxidant status by a synergistic effect between bioactive compounds and symbiotic microbiota-induced activation of redox-dependent cell signaling. Among the molecular mechanisms involved in hormesis, raised levels of the nuclear factor erythroid-2-related factor 2 (Nrf2) have been found to prevent many chronic inflammatory diseases, including cardiovascular, kidney, and lung diseases, toxic liver damage, cancer, metabolic syndrome, inflammatory bowel disease, autoimmune diseases and HIV/AIDS. Nrf2 is involved in the neuroprotective effects of bioactive compounds, as well as in the reduction of chronic neuropathic pain and depression in individuals with locomotor impairment.

In this Special Issue, we invite investigators to contribute original research articles based on both in vitro, in animal models and human studies, as well as short or comprehensive reviews aiming to evaluate hormesis in health, impairment, diseases, and chronic low-grade inflammation.

Potential topics include but are not limited to the following:

• Human or animal studies evaluating the hormetic effects of exercise, diet, functional foods, nutraceuticals, probiotics, prebiotics, and symbiotics on oxidative stress and chronic low-grade inflammation
• Anti-inflammatory effects of regular exercise in non-communicable diseases
• Recent insights into the relationship between microbiota and exercise- or diet-induced hormesis
• Molecular mechanisms of hormesis in health, chronic low-grade inflammation, diseases, and physical and cognitive impairment
• Recent studies on oxidative stress mediated mechanisms in healthy ageing and inflammation
• The role of diet and antioxidants in sport-induced adaptations
• Redox-modulated molecular pathways involved in aged-related diseases (cancer, sarcopenia, osteopenia, immune-senescence, and metabolic, cardiovascular, and neurodegenerative diseases)