Mushroom Polysaccharides as Functional Food Ingredients for Alleviating Exercise-Induced Fatigue: A Review of Efficacy, Mechanisms, and Structure–Function Relationships

Exercise-induced fatigue is often accompanied by a poor mental state, reduced work efficiency, and decreased athletic performance. Mushroom polysaccharides have been shown in recent years to have a positive effect on alleviating exercise-induced fatigue. This review comprehensively analyzes the extraction methods, structure-activity relationships, and mechanisms of mushroom polysaccharides in alleviating exercise-induced fatigue from 1999 to 2025. Research has revealed that mushroom polysaccharides not only directly alleviate exercise-induced fatigue by regulating gut microbiota but also indirectly mitigate it by influencing oxidative stress, inflammatory factors, and energy metabolism. Moreover, the structure of mushroom polysaccharides is closely related to their biological activity, but there is no systematic consensus on the key structural feature responsible for their antifatigue effects. The purpose of this review is to provide new theoretical evidence for the relationship between the polysaccharide structure and activity and to pave the way for the development of antifatigue functional food ingredients based on mushroom polysaccharides.