Interactions between exercise and nutrition to prevent muscle waste during ageing
Interactions between exercise and nutrition to prevent muscle waste during ageing
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DOI：
10.1111/j.1365-2125.2012.04456.x
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发表时间：
2013-03-01
影响因子：
3.4
通讯作者：
Phillips, Stuart M.
中科院分区：
文献类型：
--
作者：
Breen, Leigh;Phillips, Stuart M.
肌肉减少症和肌无力（年龄相关的力量丧失）的根本原因尚未完全阐明，但可能是生活方式或炎症和内分泌特征改变的结果或组合。很清楚的是，功能能力有限，死亡风险升高。从机制上讲，肌肉萎缩是由于肌肉蛋白质合成（MPS）和肌肉蛋白质分解（MPB）之间的不平衡引起的长期净负肌肉蛋白质平衡的结果。骨骼肌的收缩负荷，通过连续型运动和氨基酸摄入都作为一个强大的刺激MPS，当结合起来，可以诱导净正蛋白质平衡和肌肉肥大。鉴于与年轻人相比，老年肌肉中的MPS对合成代谢刺激的反应迟钝，因此收缩和营养干预的综合效果和操作以优化肌肉的抗张力对于抵消肌肉减少症可能非常重要。具体而言，剂量，吸收动力学，亮氨酸含量，但较少的摄入时间，是重要的决定因素的mRNA翻译信号转导反应调节MPS。此外，阻力运动诱导的MPS和肥大率似乎取决于运动量（以实现最大肌纤维招募），而不是提升的绝对负荷。最近在年轻人中进行的一些研究表明，收缩可以被操纵，从而支持了这一观点;允许低负荷举重有效地刺激MPS的速率达到与传统高负荷相当的水平，这一发现对有兴趣进行抗阻运动的老年人具有重要意义。
The underlying cause of sarcopenia and dynapenia (age-related strength loss) are not fully elucidated, but may be the result, or combination, of alterations in lifestyle or inflammatory and endocrine profiles. What is clear is that functional ability is limited and mortality risk is elevated. Mechanistically, muscle atrophy is the result of the prolonged periods of net negative muscle protein balance, brought about by the imbalance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). Contractile loading of skeletal muscle, through resistive-type exercise and amino acid ingestion both act as a strong stimulus for MPS and, when combined, can induce a net positive protein balance and muscle hypertrophy. Given that MPS in older muscles displays a blunted response to anabolic stimuli compared with the young, the combined effect and manipulation of contractile and nutrient interventions to optimize muscle anabolism could be extremely important for counteracting sarcopenia. Specifically, the dose, absorption kinetics, leucine content, but less-so the timing of ingestion, are important determinants of the mRNA translational signalling response regulating MPS. In addition, resistance exercise-induced rates of MPS and hypertrophy appear to be dependent on exercise volume (to achieve maximal muscle fibre recruitment), as opposed to the absolute load that is lifted. A number of recent studies in young adults lend weight to this notion by showing that contraction can be manipulated; allowing low load weight lifting to effectively stimulate rates of MPS to a level comparable with traditional high loads, a finding with important implications for older adults interested in undertaking resistance exercise.