Effects of Obesity in the Aged

项目概要/摘要 70%的老年人（60岁以上）超重或肥胖，许多人不能或不愿意锻炼 由于运动不耐受和/或劳力性呼吸困难（DOE）。我们发现了大量的肥胖症- 可能影响肥胖成年人运动耐量和DOE的相关效应。我们还确定 非肥胖老年人中许多与年龄相关的解释性限制。然而，目前还不清楚肥胖是否- 相关和衰老相关的影响结合联合收割机，降低运动耐量，引发DOE，或有助于 老年肥胖成人的呼吸道症状。我们认为，老年人中许多与肥胖有关的影响， 肥胖的成年人是低肺容量呼吸的结果，即，功能性剩余能力降低 (FRC)静息时和运动时呼气末肺容积（EELV）。胸壁脂肪增加 产生低FRC和EELV水平，其中呼吸限制如呼气流量限制（EFL）， 由于年龄相关的最大呼吸困难下降， 低肺容量时的呼气流量。我们的总体假设是，呼吸限制，运动 不耐受，DOE，和呼吸道症状的老年肥胖成人是由于机械负荷的 胸部和低肺容量呼吸。我们建议使用外部胸甲来验证这一假设 (i.e.,胸部上的塑料壳）以机械地卸载胸壁。这将减少 从而增加休息时的FRC和运动时的EELV，并可能减少 锻炼时呼吸。本申请的总体目标是研究 与老年人相比，肥胖对老年肥胖成年人的肺功能、运动耐量和DOE的影响 没有肥胖的成年人，使用一种新型探头在休息时和 锻炼的我们将使用1）持续负胸甲压力，2）辅助双相胸甲 通气，以减少肥胖相关的影响，在老年肥胖的成年人。我们的方法是检查 老年肥胖患者机械性和非机械性去负荷的呼吸功能、运动耐量和DOE 男性和女性（65-75岁），包括有呼吸道症状的人，与老年人相比 没有肥胖。具体目标：我们将测试以下假设：目标1）肥胖将减少 呼吸功能，但在有呼吸道症状的老年肥胖成人中更大程度上;目的2） 肥胖会降低运动耐量，但不会降低心肺功能，老年肥胖者除外。 有呼吸道症状的成年人，两者都可能减少;目标3）肥胖会增加DOE， 在更大程度上，在有呼吸道症状的老年肥胖成人中;以及目的4）机械 胸部减压可改善老年人的呼吸功能、运动耐量和DOE。 肥胖的成年人，但在更大程度上在老年肥胖与呼吸道症状。这些结果 将对DOE老年肥胖患者的护理产生广泛和直接的临床影响。

PROJECT SUMMARY/ABSTRACT Seventy% of older adults (60+ yr) are overweight or obese and many are unable or unwilling to exercise due to exercise intolerance and/or dyspnea on exertion (DOE). We have identified numerous obesity- related effects that could influence exercise tolerance and DOE in obese adults. We have also identified many age-related ventilatory constraints in nonobese older adults. However, it is unclear whether obesity- related and aging-related effects combine to reduce exercise tolerance, provoke DOE, or contribute to respiratory symptoms in older obese adults. We propose that many of the obesity-related effects in older obese adults are the result of low lung volume breathing, i.e., a reduction in functional residual capacity (FRC) at rest and end-expiratory lung volume (EELV) during exercise. Increased fat on the chest wall produces low FRC and EELV levels, where breathing limitations like expiratory flow limitation (EFL) and enhanced perception of dyspnea are more likely to occur due to the age-related decline in maximal expiratory flow at low lung volumes. Our overall hypothesis is that respiratory limitations, exercise intolerance, DOE, and respiratory symptoms in older obese adults are due to mechanical loading of the thorax and low lung volume breathing. We propose to test this hypothesis with the use an external cuirass (i.e., a plastic shell over the thorax) to mechanically unload the chest wall. This will decrease the load on the thorax thereby increasing FRC at rest and EELV during exercise, and potentially decrease the work of breathing during exercise. The overall objective of this application is to investigate the effects of obesity on lung function, exercise tolerance, and DOE in older obese adults as compared with older adults without obesity, using a novel probe for mechanically unloading the thorax at rest and during exercise. We will use 1) continuous negative cuirass pressure, and 2) assisted biphasic cuirass ventilation to decrease obesity-related effects in older obese adults. Our approach will be to examine respiratory function, exercise tolerance, and DOE with and without mechanical unloading in older obese men and women (65-75 yr), including those with respiratory symptoms, as compared with older adults without obesity. Specific Aims: We will test the following hypotheses: Aim 1) Obesity will decrease respiratory function but to a greater extent in older obese adults with respiratory symptoms; Aim 2) Obesity will decrease exercise tolerance but not cardiorespiratory fitness, except in older obese adults with respiratory symptoms where both may be reduced; Aim 3) Obesity will increase DOE but to a greater extent in older obese adults with respiratory symptoms; and Aim 4) Mechanical unloading of the thorax will improve respiratory function, exercise tolerance, and DOE in older obese adults, but to a greater extent in older obese adults with respiratory symptoms. These results will have broad and immediate clinical impact on the care of older obese adults with DOE.