Purdom Troy, Kravitz Len, Dokladny Karol, Mermier Christine
1Department of Health, Athletic Training, Recreation, and Kinesiology, Longwood University, 201 High St, Farmville, VA 23909 USA.
2Department of Health, Exercise & Sports Sciences, University of New Mexico, Albuquerque, NM USA.
J Int Soc Sports Nutr. 2018 Jan 12;15:3. doi: 10.1186/s12970-018-0207-1. eCollection 2018.
Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO, is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox). Due to limitations within FA transport across the cell and mitochondrial membranes, FAox is limited at higher exercise intensities. The point at which FAox reaches maximum and begins to decline is referred to as the crossover point. Exercise intensities that exceed the crossover point (~65% VO) utilize CHO as the predominant fuel source for energy supply. Training status, exercise intensity, exercise duration, sex differences, and nutrition have all been shown to affect cellular expression responsible for FAox rate. Each stimulus affects the process of FAox differently, resulting in specific adaptions that influence endurance exercise performance. Endurance training, specifically long duration (>2 h) facilitate adaptations that alter both the origin of FAs and FAox rate. Additionally, the influence of sex and nutrition on FAox are discussed. Finally, the role of FAox in the improvement of performance during endurance training is discussed.
在次最大强度运动期间，脂质作为能量供应的燃料来源，源自皮下脂肪组织衍生的脂肪酸（FA）、肌内甘油三酯（IMTG）、胆固醇和膳食脂肪。这些脂肪来源以各种方式促进脂肪酸氧化（FAox）。脂肪酸以最大能力进行调节和利用主要发生在运动强度为45%至65%VO₂之间，这被称为最大脂肪氧化（MFO），以克/分钟为单位进行测量。脂肪酸氧化在次最大强度运动期间发生，但也与碳水化合物氧化（CHOox）互补。由于脂肪酸跨细胞膜和线粒体膜运输存在限制因素，脂肪酸氧化在较高运动强度下受到限制。脂肪酸氧化达到最大值并开始下降的点被称为交叉点。超过交叉点（约65%VO₂）的运动强度会利用碳水化合物作为能量供应的主要燃料来源。训练状态、运动强度、运动持续时间、性别差异和营养均已被证明会影响负责脂肪酸氧化速率的细胞表达。每种刺激对脂肪酸氧化过程的影响各不相同，从而导致特定的适应性变化，进而影响耐力运动表现。耐力训练，特别是长时间（>2小时）的训练，有助于产生适应性变化，这些变化会改变脂肪酸的来源和脂肪酸氧化速率。此外，还讨论了性别和营养对脂肪酸氧化的影响。最后，探讨了脂肪酸氧化在耐力训练中提高运动表现方面的作用。
