Overcoming the blunted response to resistance exercise with fish oil to maximise the maintenance of muscle mass in older people

骨骼肌是人体最大的器官，在决定我们的身体能力和整体健康方面发挥着许多重要作用。骨骼肌的一个主要功能是执行许多日常任务，例如从椅子上站起来或上公共汽车，这些任务通常被称为功能性能力。在健康衰老期间，肌肉大小每年减少约0.5-2%（称为肌肉减少症），同时功能能力下降。这可能导致生活质量下降和独立性丧失，这两种情况显然都是不可取的。骨骼肌减少症的发病率在50-70岁之间约为20%，在80岁以上的人群中约为50%，绝对人数和人口的平均年龄都在上升。在所有年龄组中，我们可以通过锻炼来增强肌肉功能，延缓肌肉减少症的发展。运动的效果取决于许多遗传和环境因素，其中营养摄入是最重要的因素之一，也是最容易改变的因素。最近的研究表明，改变摄入的脂肪酸类型可能对肌肉功能有积极影响。在老年人身上进行的研究还很少。这一点很重要，因为动物模型的发现并不能完全转移到人类身上。因此，当前提案的主要目的是调查摄入二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）的影响，这是在油性鱼类中发现的长链多不饱和脂肪酸，对老年人抗阻训练计划的反应。进一步的目标是确定导致这些适应性反应的机制。该项目将围绕一项为期18周的大型抗阻训练/营养（EPA/DHA）干预，参与者包括65岁以上的男性和女性。有三个主要的研究问题和实验源于这种干预。1)在抗阻训练中，EPA和DHA的消耗是否会导致力量、力量和功能能力的更大增长？为了回答这个问题，一系列的肌肉表现和功能能力的测量将被评估。2) EPA和DHA的摄入是否会增加肌肉的大小和质量，减少肌肉内的脂肪量并减少炎症？为了解决这个问题，参与者将在干预前后对他们的肌肉和血液样本进行核磁共振成像。这将允许计算肌肉量/脂肪含量和炎症标志物的循环水平。3)单次抗阻运动后，EPA和DHA的摄入是否会增强参与控制肌肉质量的分子的活性？对于这个问题，我们将在一次训练之前和之后获得肌肉样本，并测量先前确定的运动对肌肉质量变化的重要分子的变化。贯穿提案的第四个目标是4)男性和女性对EPA/DHA和抗阻运动的组合反应不同吗？蛋白质代谢的差异以前已经注意到性别之间的差异，但对这些差异的调查往往被忽视。我们将通过研究男性和女性群体的反应来调查这一点。总之，拟议项目的目的是测试一种假设，即食用油性鱼类中的脂肪酸将改善老年人对抗阻训练干预的反应。这项建议的主要成果将是确定鱼油对老年人肌肉适应的有益作用，为改善老年人的生活质量开辟一种广泛可用的治疗策略。由于英国人口年龄的增长，这种策略尤为重要。

Skeletal muscle is the largest organ in the human body and has many important roles in determining our physical abilities and overall wellbeing. One major function of skeletal muscle is to carry out many daily tasks, such as rising from a chair or getting on a bus, tasks often referred to as functional abilities. During healthy ageing muscle size is reduced by approximately 0.5-2% a year (known as sarcopenia), with concurrent reductions in functional abilities. This can result in a reduction in quality of life and loss of independence, both of which are clearly not desirable. The incidence of sarcopenia is around 20% between 50-70 years and around 50% in those over 80 years, with the absolute numbers and the average age of the population rising.One method through which we can enhance muscle function and retard the progression of sarcopenia, across all age groups, is through exercise. The effectiveness of exercise will depend on a number of genetic and environmental factors, with nutritional intake being one of the most important and easily altered. Recent research has suggested that altering the type of fatty acids consumed may have a positive effect on muscle function. Little research is yet to be carried out in elderly humans. This is important as that findings from animal models are not definitively transferrable to humans. The main aim of the current proposal, therefore, is to investigate the effect the consumption of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), long chain polyunsaturated fatty acids found in oily fish, on the response to a resistance training programme in the elderly. A further aim is to determine the mechanisms which result in these adaptive responses. The project will be centred round a large 18 week resistance training/nutritional (EPA/DHA) intervention with both males and females over the age of 65 years. There are three main research questions and experiments stemming from this intervention. 1) Does the consumption of EPA and DHA result in a greater increase in strength, power and functional abilities in response to resistance training? To answer this question a series of measures of muscular performance and functional abilities will be assessed. 2) Does the consumption of EPA and DHA increase the size and quality of muscles, reduce the amount of fat found within the muscle and decrease inflammation? To address this question the participants will have MRI images of their muscles and blood samples taken before and after the intervention. This will allow the calculation of muscle mass/fat content and circulating levels of inflammatory markers. 3) Does the consumption of EPA and DHA enhance the activity of the molecules involved in controlling muscle mass after a single bout of resistance exercise? For this question we will obtain muscle samples before and after a single training session and measure changes in molecules previously identified as important in the changes in muscle mass in response to exercise. A fourth aim running throughout the proposal is 4) Do males and females respond differently to the combination of EPA/DHA and resistance exercise? Differences in protein metabolism have previously been noted between genders and yet the investigation of these differences is often overlooked. We will investigate this by studying responses in groups of males and females.In summary, the aim of the proposed project is to test the hypothesis that the consumption of fatty acids found in oily fish will improve the response of an elderly population to a resistance training intervention. The major outcome of the proposal would be in establishing a beneficial effect of fish oil on muscular adaptation in the elderly, opening up a widely available therapeutic strategy for an improvement in the quality of life in the elderly population. Such strategies are of particular importance due to the increasing age of the UK population.