Spriet Lawrence L
Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada.
Nestle Nutr Inst Workshop Ser. 2011;69:39-53; discussion 53-8. doi: 10.1159/000329281. Epub 2012 Jan 18.
Fat is an important fuel for exercise but plays a secondary role to carbohydrate (CHO). Increasing fat use during exercise can decrease the reliance on CHO and spare CHO for later in training sessions or competitions that depend on CHO for success. The pathways that metabolize and oxidize fat are activated more slowly than CHO at the onset of exercise and reach a maximum at moderate exercise intensities. As exercise intensity increases to ∼75% VO(2max) and beyond, fat metabolism is inhibited: using CHO will increase the amount of energy produced per liter of oxygen consumed. The capacity for fat use during exercise is increased by aerobic training and the dietary combination of little or no CHO intake and high fat intake. Fat oxidation is very dependent on the mitochondrial volume of muscle but other key sites of regulation include release of fat from storage forms and fat transport across plasma and mitochondrial membranes. This chapter examines the control of fat metabolism during moderate and intense exercise with an emphasis on human findings and the adaptations that occur with aerobic training and other acute nutritional manipulations. Recent work using molecular and cellular compartmentalization techniques have advanced the knowledge in this area.
脂肪是运动的重要燃料，但相对于碳水化合物（CHO）而言，其作用是次要的。在运动过程中增加脂肪的利用可以减少对碳水化合物的依赖，并为后续依赖碳水化合物取得成功的训练课程或比赛节省碳水化合物。在运动开始时，代谢和氧化脂肪的途径比碳水化合物激活得更慢，并且在中等运动强度时达到最大值。当运动强度增加到约75%最大摄氧量（VO₂max）及以上时，脂肪代谢受到抑制：使用碳水化合物会增加每消耗一升氧气所产生的能量。通过有氧训练以及少量或不摄入碳水化合物和高脂肪摄入的饮食组合，可以提高运动过程中脂肪利用的能力。脂肪氧化非常依赖于肌肉的线粒体体积，但其他关键的调节部位包括脂肪从储存形式的释放以及脂肪跨血浆和线粒体膜的转运。本章探讨了中等强度和高强度运动期间脂肪代谢的控制，重点关注人体研究结果以及有氧训练和其他急性营养干预所产生的适应性变化。最近使用分子和细胞区室化技术的研究推动了该领域知识的发展。
