Gonzalez Javier T
Department for Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Northumberland Building, Newcastle upon Tyne, UK.
Nutrition. 2014 Sep;30(9):961-7. doi: 10.1016/j.nut.2013.12.001. Epub 2013 Dec 14.
Attenuating blood glucose excursions in the postprandial state have the capacity to reduce the risk for cardiovascular disease, type 2 diabetes, and mortality, even in apparently healthy populations. Nearly a century ago, it was reported that oral glucose tolerance is improved by prior glucose consumption. This was termed the second-meal phenomenon and is also seen with consumption of mixed-macronutrient-containing meals. In this context, a number of mechanisms probably contribute to the attenuation of glycemia, including gastric emptying, early-phase insulin secretion, hepatic glucose output, and muscle glucose uptake. More recently, a paradoxical second-meal phenomenon has been observed in the immediate postexercise period whereby prior meal consumption deteriorated glucose tolerance. The mechanisms regulating the postexercise second-meal phenomenon are less clear, but are likely to involve an increase in intestinal absorption, greater hepatic glucose output, and under circumstances of muscle damage, reductions in muscle glucose uptake. Further work is required to confirm these mediating factors and to characterize the time course of this paradox, which is likely to only exist within the first 4 h following exercise. Critically, this acute postexercise phenomenon should be maintained in the perspective of the benefits of chronic exercise training, which for the majority of individuals improves glycemic control and reduces many health risks including those associated with exaggerated postprandial glycemia.
即使在看似健康的人群中，减轻餐后血糖波动也有能力降低心血管疾病、2型糖尿病和死亡率的风险。近一个世纪前，有报道称预先摄入葡萄糖可改善口服葡萄糖耐量。这被称为第二餐现象，在摄入含多种宏量营养素的餐食时也会出现。在这种情况下，多种机制可能有助于血糖的降低，包括胃排空、早期胰岛素分泌、肝脏葡萄糖输出和肌肉葡萄糖摄取。最近，在运动后的即刻观察到一种矛盾的第二餐现象，即预先进餐会使葡萄糖耐量恶化。调节运动后第二餐现象的机制尚不清楚，但可能涉及肠道吸收增加、肝脏葡萄糖输出增加，以及在肌肉损伤的情况下，肌肉葡萄糖摄取减少。需要进一步的研究来证实这些介导因素，并描述这种矛盾现象的时间进程，这种现象可能仅在运动后的前4小时内存在。至关重要的是，应从长期运动训练的益处的角度看待这种急性运动后现象，对于大多数人来说，长期运动训练可改善血糖控制，并降低包括与餐后高血糖相关的风险在内的许多健康风险。
