Exercise in Burn Survivors

描述（由申请人提供）：美国每年有40,000 - 70,000人因烧伤相关损伤住院，其中16%（6,400至11,200）严重烧伤，烧伤面积至少占其全身表面积（BSA）的20%。20年前，覆盖50% BSA的烧伤是致命的，而目前90% BSA烧伤的患者存活下来。医疗保健的这些改进的结果是，成千上万的人忍受烧伤的长期后果。例如，烧伤后数年，疲劳是一种“几乎普遍的抱怨”，是阻碍这些人重返工作岗位和进行日常生活活动的主要障碍。我们发现，约76%愈合良好的烧伤受试者（损伤多年后）具有有氧适能/能力，通过最大摄氧量（V¿O2max）来测量，相对于年龄和性别，其有氧适能/能力处于最低的20百分位数，符合正常值47。根据大量有关有氧能力与死亡率、心血管风险和生活质量的研究，76%的严重烧伤患者的死亡风险将增加3至5倍，总体健康状况较差，并且在2岁、15岁、16岁、86岁、100岁和116岁时更有可能需要依赖护理。鉴于这些发现，本研究将解决以下问题，这些问题的答案对烧伤患者的健康和完全康复至关重要：1)严重烧伤患者在损伤后数年出现低有氧适能的机制是什么？2)以前遭受过严重烧伤的人是否可以改善他们的有氧能力，如果可以，是通过什么机制改善的？为了解决这些问题和相关假设，在评估前至少2年经历过严重烧伤的受试者，烧伤面积为其BSA的20- 35%、40-55%和60 - 60%，将参加为期6个月的运动训练方案。在训练方案之前和之后，将评估受试者的有氧能力（V¿O2max）、影响VO2max的中枢和外周心血管变量（即稳态和最大心输出量、卒中量、心率和动静脉氧差异），以及改善氧化能力的肌肉生化和组织学标志物。还将评估受试者左心室收缩/舒张功能、生活质量、身体组成和日常生活活动的量化。这些程序将解决一个总体假设，即在烧伤愈合良好的个体中，运动训练增加的最大摄氧量（及其相关机制）受到烧伤程度的影响。所获得的信息将确定烧伤幸存者在实现身体活动的益处方面的潜力和局限性，这些益处对心血管健康、减少老年依赖性和改善生活质量具有重要意义2,15,16,100，同时作为基于运动的康复计划可以实施的基础，以改善严重烧伤个体受伤后数年的健康。

DESCRIPTION (provided by applicant): Each year 40,000 - 70,000 individuals in the US are hospitalized for burn-related injuries, with 16% (6,400 to 11,200) having severe burns covering at least 20% of their total body surface area (BSA). Twenty years ago burns covering 50% BSA were fatal, while presently patients with 90% BSA burned are surviving. The outcome of these improvements in medical care is that hundreds of thousands of individuals endure the long- term consequences of burn injuries. For example, years following the burn injury fatigue is an "almost universal complaint" as a major barrier preventing such individuals from returning to work and performing activities of daily living 60, 65. We identified that ~76% of well-healed burned subjects (many years post-injury) have an aerobic fitness/capacity, measured by maximal oxygen uptake (V¿ O2max), in the lowest 20th percentile relative to age and sex matched normative values 47. Based upon numerous studies relating aerobic capacity with mortality, cardiovascular risk, and quality of life, ~76% of severely burned individuals will have 3 to 5 fold greater mortality risk, have poorer general health, and will be more likely to require dependent care as they age 2, 15, 16, 86, 100, 116. Given these findings, the proposed work will address the following questions, the answers to which are vital to the health and full rehabilitation of the recovered burned patient: 1) What are the mechanisms resulting in low aerobic fitness in severely burned individuals years after the injury? 2) Can individuals who previously suffered significant burn injuries improve their aerobic capacity and if so by what mechanisms? To address these questions and related hypotheses, subjects who experienced severe burn injuries covering 20- 35%, 40-55%, and >60% of their BSA a minimum of 2 years prior to assessment will participate in a 6 month exercise training protocol. Prior to and followin the training protocol, subjects will be evaluated for aerobic capacity (V¿ O2max), central and peripheral cardiovascular variables that influence VO2max (i.e., steady-state and ¿ maximum cardiac output, stroke volume, heart rate, and arteriovenous oxygen differences), and muscle biochemical and histological markers of improved oxidative capacity. Subjects will also be evaluated for left ventricular systolic/diastolic function, quality of life, body composition, and quantification of activities of daily living. These procedures will address the overall hypothesis that increases in VO2max (and related mechanisms) with exercise training in well-healed burned individuals are influenced by the extent of the burn injury. The obtained information will identify burn survivors' potential and limitations in realizing the benefits of physical activity tat are important for cardiovascular health, reduced dependency with aging, and improvements in quality of life 2, 15, 16, 100, while serving as the foundation by which exercise-based rehabilitation programs can be implemented to improve the health of severely burned individuals years following the injury.