Effect of fat loss on functional and cardiovascular benefits of aerobic exercise

减脂对有氧运动功能和心血管益处的影响

• 批准号: 7904997
• 负责人: Barbara J Nicklas
• 金额: $ 70.22万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-04 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7904997
• 关键词: Abdomen; Adult; Advocate; Aerobic; Aerobic Exercise; Affect; Aging; Blood Pressure; Body Weight decreased; Body fat; Caloric Restriction; Cardiovascular system; Clinical; Data; Dose; Educational Intervention; Elderly; Energy Intake; Exercise; Exercise Tolerance; Fatty acid glycerol esters; Goals; High Prevalence; Individual; Intervention; Knowledge; Lead; Lipids; Location; Muscle; Myocardium; Obesity; Organ; Outcome; Participant; Pericardial body location; Physiological Adaptation; Population; Public Health; Randomized; Randomized Clinical Trials; Randomized Controlled Trials; Recommendation; Risk; Risk Factors; Sampling; Skeletal Muscle; Stimulus; Testing; Training; Training Programs; Uncertainty; Visceral; Walking; Weight; Woman; age related; arm; blood lipid; cardiovascular disorder risk; clinical practice; design; disability; experience; fitness; functional decline; glucose tolerance; high risk; improved; inflammatory marker; men; programs; prospective; public health relevance; randomized trial; response; sedentary; skeletal

DESCRIPTION (provided by applicant): Aging is associated with declines in aerobic capacity, exercise tolerance, and functional endurance that lead to physical disability. To date, regular exercise is the only therapy to consistently improve aerobic function, and perhaps delay the onset of disability. However, some data show that the maximal efficacy of exercise for improving aerobic function is blunted by obesity. In addition, our preliminary data show a potential dose-response benefit of concomitant fat loss on exercise-induced improvements in aerobic function. Thus, combining an exercise intervention with caloric restriction resulting in fat loss may be more efficacious for improving aerobic function than exercise alone in obese elderly, a population at high risk for disability. This study is a 3-arm, 5-month randomized, clinical trial in 180 older (65-79 yrs), obese (BMI=30-34.9 kg/m2), sedentary men and women designed to determine whether the amount of fat loss (achieved through controlled underfeeding) affects the magnitude of improvement in aerobic function (maximal aerobic capacity and endurance) in response to a standardized exercise training stimulus that follows current recommendations. Participants will be randomized to an exercise training intervention (moderate-intensity treadmill walking, 4 d/wk) alone (EX Only), exercise with moderate caloric restriction (-250 kcal/d deficit) designed for low fat loss (EX+Low CR; ~3.4 kg fat loss), or exercise with intensive caloric restriction (-750 kcal/d deficit) designed for high fat loss (EX+High CR; ~10.2 kg fat loss). The Specific Aims are to determine the effects of adding moderate and intensive caloric restriction to a standardized aerobic exercise training intervention on: 1) maximal aerobic capacity and walking endurance (6-minute walking distance); 2) cardiovascular disease risk factors (inflammatory markers, blood lipids, blood pressure, glucose tolerance and endothelial function); and 3) inter- muscular, abdominal visceral and pericardial fat volumes. We will also determine whether improvements in aerobic function and CVD risk factors are related to the degree of total and regional fat loss. If our hypotheses are confirmed, this study will provide the first prospective and definitive evidence from a randomized, controlled trial that loss of fat mass augments exercise-induced improvements in aerobic function. These findings will provide persuasive evidence that addition of caloric restriction to an exercise intervention in older, obese adults may be more effective for improving aerobic function than exercise alone, and are likely to change traditional reluctance to recommend some caloric restriction during an exercise program in older adults for the purpose of maximizing their exercise efforts. In addition, by assessing lipid accumulation around visceral organs, and skeletal and cardiac muscle, before and after the interventions, we will also be able to determine the contribution of fat loss in these local depots to the magnitude of exercise-induced improvement in both functional and CVD risk factor outcomes. PUBLIC HEALTH RELEVANCE: This study will determine whether older, obese men and women who lose more fat during an exercise training program will experience greater improvements in fitness and endurance as a result of the exercise training than those who do not lose any fat, or very little fat. This knowledge could lead to a stronger clinical recommendation for inclusion of weight loss to benefit obese, older individuals who exercise. The results will also provide information on whether the location of fat loss is important for improving fitness and cardiovascular disease risk.

描述（由申请人提供）：衰老与有氧能力、运动耐力和功能耐力的下降有关，从而导致身体残疾。迄今为止，定期锻炼是持续改善有氧功能并可能延缓残疾发生的唯一疗法。然而，一些数据表明，运动改善有氧功能的最大功效因肥胖而减弱。此外，我们的初步数据显示，伴随减脂对运动引起的有氧功能改善具有潜在的剂量反应益处。因此，对于残疾高风险人群的肥胖老年人来说，将运动干预与热量限制相结合以减少脂肪可能比单独运动更有效地改善有氧功能。这项研究是一项为期 5 个月的 3 组随机临床试验，受试者为 180 名老年人（65-79 岁）、肥胖者（BMI=30-34.9 kg/m2）、久坐的男性和女性，旨在确定减脂量（通过控制喂养不足实现）是否会影响有氧功能（最大有氧能力和耐力）的改善程度，以响应标准化运动训练刺激 目前的建议。参与者将被随机分配到单独的运动训练干预组（中等强度跑步机行走，每周 4 天）（仅 EX）、专为低脂肪减少而设计的中等热量限制（-250 kcal/d 赤字）运动（EX+低 CR；约 3.4 kg 脂肪损失）或为高脂肪损失而设计的强化热量限制（-750 kcal/d 赤字）运动（EX+高 CR；约 10.2 kg 脂肪损失）。具体目标是确定在标准化有氧运动训练干预中添加中度和强化热量限制对以下方面的影响：1) 最大有氧能力和步行耐力（6 分钟步行距离）； 2）心血管疾病危险因素（炎症标志物、血脂、血压、糖耐量和内皮功能）； 3) 肌间、腹部内脏和心包脂肪量。我们还将确定有氧功能和心血管疾病危险因素的改善是否与总体和局部脂肪减少的程度有关。如果我们的假设得到证实，这项研究将提供来自随机对照试验的第一个前瞻性和明确的证据，表明脂肪量的减少会增强运动引起的有氧功能的改善。这些研究结果将提供有说服力的证据，证明在老年肥胖者的运动干预中加入热量限制可能比单独运动更有效地改善有氧功能，并且可能改变传统上不愿在老年人运动计划中建议进行一些热量限制以最大限度地提高运动强度的做法。此外，通过评估干预前后内脏器官、骨骼和心肌周围的脂质积累，我们还将能够确定这些局部储存库中脂肪减少对运动引起的功能和心血管疾病危险因素结果改善程度的贡献。 公共健康相关性：本研究将确定在运动训练计划中减掉更多脂肪的老年肥胖男性和女性是否会比那些没有减掉任何脂肪或减掉很少脂肪的人在运动训练中获得更大的体能和耐力改善。这些知识可能会导致更强有力的临床建议，将减肥纳入其中，以造福肥胖的老年锻炼者。研究结果还将提供有关减脂部位对于改善健康和心血管疾病风险是否重要的​​信息。