Basics in clinical sports nutrition: Physical activity, muscle and clinical nutrition.

Physical activity and nutrition are inextricably linked in maintaining muscle and overall health, enhancing metabolic resilience, and preventing age-related muscle loss. Exercise acts as a powerful physiological stressor, inducing acute metabolic, endocrine, and immunological responses, while long-term training elicits structural and functional adaptations at the muscular, cardiovascular, and systemic levels. Proper nutritional strategies, aligned with the type, intensity, and duration of physical activity, provide the necessary substrates to fuel exercise, optimize recovery, and support muscle protein synthesis and immune resilience. This integrative approach not only enhances athletic performance but also serves as a critical tool in the prevention and management of chronic diseases, including obesity, type 2 diabetes and cardiovascular disease. Emerging evidence further underscores the importance of skeletal muscle as a metabolic and endocrine organ, producing myokines which, with other exerkines, mediate the systemic health benefits of exercise. As a result, the evolving field of clinical sports nutrition bridges the gap between performance-oriented sports nutrition and evidence-based clinical care for physically active individuals across the health spectrum. By combining exercise physiology, clinical nutrition, and applied sports science, this multidisciplinary model provides a robust framework for advancing metabolic health, functional capacity, and performance in diverse populations.