Garcia-Dominguez Esther, Gomez-Cabrera Maria Carmen, Gonzalez Gloria Olaso
Freshage Research Group, Department of Physiology, Faculty of Medicine, University of Valencia, CIBERFES, Fundación Investigación Hospital Clínico Universitario/INCLIVA, Valencia, Spain.
Department of Physiology, School of Medicine, University of Valencia, Valencia, Spain.
Adv Exp Med Biol. 2025;1478:491-510. doi: 10.1007/978-3-031-88361-3_21.
Metabolism involves not only the conversion of nutrient fuel into usable energy but also includes the synthesis, modification, and exchange of cellular building blocks, acting as a regulator and sensor of cellular activities. Various components within metabolic pathways can affect cellular responses. A significant portion of daily energy intake is necessary for sustaining life, and physical activity demands are added to an intricately integrated machinery. Studying elite human performance offers valuable information about the molecular, cellular, tissue, and overall body adjustments to intense metabolic demands. Moreover, understanding the mechanisms and pathways activated during exercise could potentially uncover new therapeutic targets for prescription in patient populations.In this book chapter, we will review the structural and functional peculiarities of our skeletal muscle cells, the myofibers. After this brief introduction, we will also give an overview of skeletal muscle metabolism depending on the intensity of the exercise. The metabolic demands and regulation of very intense, intermittent, or "stop-and-go" sports and long-lasting exercise efforts will be reviewed. The main reasons to explain the importance of carbohydrates in supporting ATP production in high-intensity exercise and the downregulation of fat metabolism at high aerobic exercise intensities in athletes are also discussed. The last section of this book chapter is devoted to the main metabolic adaptations to cardiorespiratory and resistance exercise training. These include exercise-induced skeletal muscle fiber-type transitions, changes in capillaries and myoglobin, improvements in mitochondrial content and function, changes in glycogen and intramuscular triglyceride skeletal muscle stores, and improvements in tolerance for acid-base imbalances.
新陈代谢不仅涉及将营养物质转化为可用能量，还包括细胞组成成分的合成、修饰和交换，它充当细胞活动的调节者和传感器。代谢途径中的各种成分会影响细胞反应。维持生命需要每日摄入相当一部分能量，而身体活动需求则被添加到一个错综复杂的整合机制中。研究精英人类表现能提供有关分子、细胞、组织以及整个身体对强烈代谢需求的调整的宝贵信息。此外，了解运动过程中激活的机制和途径可能会揭示患者群体新的处方治疗靶点。在本章中，我们将回顾骨骼肌细胞（即肌纤维）的结构和功能特性。在这个简要介绍之后，我们还将根据运动强度概述骨骼肌代谢。我们将回顾非常剧烈、间歇性或“停停走走”运动以及持久运动的代谢需求和调节。还将讨论解释碳水化合物在高强度运动中支持三磷酸腺苷（ATP）生成的重要性以及运动员在高有氧运动强度下脂肪代谢下调的主要原因。本章的最后一部分将专门讨论心肺和抗阻运动训练的主要代谢适应。这些包括运动诱导的骨骼肌纤维类型转变、毛细血管和肌红蛋白的变化、线粒体含量和功能的改善、糖原和骨骼肌内甘油三酯储存的变化以及对酸碱失衡耐受性的提高。
