The global proliferation of plastic materials has led to the widespread presence of micro- and nanoplastics (MNPs) across environmental and biological systems, raising increasing concerns regarding their potential implications for human health. While a growing body of literature has investigated the toxicological effects of MNP exposure, research has largely focused on general populations, with limited attention to physically active individuals. Athletes represent a distinct physiological subgroup characterized by elevated ventilation rates, increased metabolic demands, and frequent interaction with synthetic environments, all of which may influence exposure pathways and biological responses to environmental contaminants. This article aims to provide a critical synthesis of current evidence on MNP exposure and its potential relevance to exercise physiology and sports medicine. Drawing on data from environmental science, toxicology, and human physiology, we examine the principal exposure pathways (inhalation, ingestion, and dermal contact) and discuss interactions between MNPs and key biological systems involved in athletic performance and recovery, including the respiratory, gastrointestinal, endocrine, nervous, and musculoskeletal systems. Particular attention is given to processes such as oxidative stress, inflammation, endocrine disruption and alterations in the gut microbiome, which may influence exercise adaptation and post-injury recovery. This work highlights MNP exposure as a potential environmental factor in sports science; however, the relationships between MNP exposure and performance outcomes remain to be established. Clarifying the relevance and the underlying mechanisms of these effects will be essential to define their potential health and performance implications and to guide evidence-based prevention and/or mitigation strategies within athletic environments.