Achten Juul, Jeukendrup Asker E
School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
Nutrition. 2004 Jul-Aug;20(7-8):716-27. doi: 10.1016/j.nut.2004.04.005.
Interventions aimed at increasing fat metabolism could potentially reduce the symptoms of metabolic diseases such as obesity and type 2 diabetes and may have tremendous clinical relevance. Hence, an understanding of the factors that increase or decrease fat oxidation is important. Exercise intensity and duration are important determinants of fat oxidation. Fat oxidation rates increase from low to moderate intensities and then decrease when the intensity becomes high. Maximal rates of fat oxidation have been shown to be reached at intensities between 59% and 64% of maximum oxygen consumption in trained individuals and between 47% and 52% of maximum oxygen consumption in a large sample of the general population. The mode of exercise can also affect fat oxidation, with fat oxidation being higher during running than cycling. Endurance training induces a multitude of adaptations that result in increased fat oxidation. The duration and intensity of exercise training required to induce changes in fat oxidation is currently unknown. Ingestion of carbohydrate in the hours before or on commencement of exercise reduces the rate of fat oxidation significantly compared with fasted conditions, whereas fasting longer than 6 h optimizes fat oxidation. Fat oxidation rates have been shown to decrease after ingestion of high-fat diets, partly as a result of decreased glycogen stores and partly because of adaptations at the muscle level.
旨在提高脂肪代谢的干预措施可能会减轻肥胖和2型糖尿病等代谢性疾病的症状，并且可能具有重大的临床意义。因此，了解增加或减少脂肪氧化的因素很重要。运动强度和持续时间是脂肪氧化的重要决定因素。脂肪氧化率从低强度到中等强度时会增加，而当强度变高时则会下降。在训练有素的个体中，最大脂肪氧化率在最大耗氧量的59%至64%之间时达到，而在一大群普通人群中则在最大耗氧量的47%至52%之间时达到。运动方式也会影响脂肪氧化，跑步时的脂肪氧化高于骑自行车时。耐力训练会引发多种适应性变化，从而导致脂肪氧化增加。目前尚不清楚诱导脂肪氧化变化所需的运动训练持续时间和强度。与空腹状态相比，在运动前数小时或运动开始时摄入碳水化合物会显著降低脂肪氧化率，而禁食超过6小时则可优化脂肪氧化。摄入高脂饮食后，脂肪氧化率已显示会下降，部分原因是糖原储备减少，部分原因是肌肉水平的适应性变化。
