This review aims to explore the potential and mechanisms of selenium-biofortified probiotics as an innovative nutritional strategy for alleviating exercise-induced physiological stress. Exercise, particularly high-intensity or exhaustive exercise, triggers a cascade of physiological perturbations, including oxidative stress, inflammatory responses, gut barrier dysfunction, and muscle damage. Traditional single-nutrient strategies, such as inorganic selenium or probiotic supplementation, are often limited by low bioavailability or a narrow scope of action. Selenium-biofortified probiotics are produced via microbial biotransformation, which converts inorganic selenium into bioavailable organic forms like selenoamino acids or selenium nanoparticles that are loaded onto active probiotic carriers. This creates a synergistic entity combining the bioactivity of selenium with the gut-modulating functions of probiotics. Their core mechanism involves establishing a multi-layered defense system: by providing substrate for key selenoproteins like glutathione peroxidase, they directly enhance endogenous antioxidant defenses; by modulating immune cytokine networks, they downregulate excessive post-exercise inflammation; through probiotic colonization and metabolites, they maintain intestinal epithelial barrier integrity, countering exercise-induced intestinal hyperpermeability; and via the gut–muscle axis, they may regulate muscle metabolism and repair. Animal studies provide evidence for improved exercise endurance and reduced damage markers, but human clinical trials show inconsistent results, highlighting the influence of study design, dosage, and individual baseline status. Future research requires high-quality, long-term human trials to elucidate specific molecular pathways and develop personalized application protocols, advancing this synergistic strategy toward precision sports nutrition.

Iron is an essential trace element that participates in multiple physiological processes, including oxygen transport, electron transfer, DNA synthesis, and red blood cell production. Iron loss is particularly severe among athletes, so maintaining iron homeostasis is crucial for sports nutrition and health. Excess iron, iron deficiency, and ferroptosis can lead to muscle disorders and health issues, including sarcopenia, muscular atrophy, myocardial fibrosis, skeletal muscle injury, cardiovascular disease, and metabolic disorders. Maintaining iron homeostasis within physiological limits is essential for athletes to sustain high-intensity performance and accelerate recovery. Therefore, a comprehensive review of the effects of iron homeostasis and ferroptosis on muscle health is significant for identifying potential therapeutic targets and developing new disease treatment and prevention strategies. This paper systematically reviews research progress on targeted therapies for iron overload and ferroptosis in muscle diseases, clarifies the impact of iron on athletes’ physiological functions and competitive performance, and explores the potential application of iron in precision nutritional regulation. It aims to provide new insights for preventing exercise-induced muscle injury, myocardial damage, and overtraining syndrome in athletes.