Mechanisms of exercise-induced improvement in drug addiction via the gut microbiota: a review

Drug addiction is a complex chronic brain disorder that not only affects neurotransmitter systems and reward pathways but is also accompanied by multisystemic alterations throughout the body. In recent years, the gut microbiota has been found to have a bidirectional association with the central nervous system, and drug addiction has been closely linked to microbial dysbiosis. Exercise, as a non-pharmacological intervention, contributes to abstinence and recovery from drug addiction. Studies have shown that drug abuse affects the gut microbiota through multifaceted changes in microbial community structure and disruptions of metabolic function, whereas modulation of the gut microbiota may alleviate the pathological processes of drug addiction by influencing microbial metabolic pathways. The overall effect of exercise on the gut microbiota is characterized by increased abundance of beneficial bacteria and reduced relative abundance of certain potentially pathogenic bacteria. Exercise may improve drug addiction primarily by regulating the gut microbiota and thereby influencing immune activation and neuroinflammation, neurotransmitter and metabolite profiles, as well as cognitive function and emotional control. Although current studies have confirmed associations among exercise, the gut microbiota, and drug addiction, whether these associations are causal remains to be further verified through more rigorous large-sample animal and human studies. By systematically reviewing relevant literature, this review focuses on the effects of exercise on drug addiction-related behaviors, gut microbiota composition, metabolite levels, and immune-inflammatory indicators. It aims to clarify the relationship among "exercise-gut microbiota-drug addiction" and explore the potential mechanisms through which exercise may intervene in drug addiction via gut microbiota-mediated pathways.