STUDY OF PHYSICAL ACTIVITIES IN THE BLSA

约翰·霍普金斯大学护理学助理教授劳拉·塔尔博特博士与我们合作，通过VO2max来评估体育活动对心血管健康的贡献。根据目前公认的特定体育活动的氧气利用估计，巴尔的摩老年纵向研究受试者进行100次活动所花费的时间被转换为METS*分钟。代谢当量是一种标准的方式来表示氧气利用调整身体大小。然后将100项活动分为三类：低水平活动（<4 METS），中等水平活动（4-6 METS）和高水平活动（bbb60 METS）。单因素分析发现，心血管健康与高水平运动（r= 0.32）、中等水平运动（r= 0.15）、体型（BMI） （r=- 0.32）和年龄（r=- 0.58）显著相关。在对这些变量的多变量分析中，身体活动独立解释了最大摄氧量1.6%的方差，而与年龄和体重指数的方差约为10%。使用回归模型，我们估计对于一个普通人来说，要增加10%的最大摄氧量，每天需要35-40分钟的高水平运动和150分钟的中等水平运动。这些计算结果支持了最近外科医生建议的日常体育活动的总体概念。目前，我们正在研究心血管健康水平或体育活动是否是死亡率的危险因素。由最大摄氧量（VO2max）评估的心血管健康是导致全因死亡率和心脏死亡率的一个重要独立因素。体育活动很重要，但与健身的程度不同。身体功能量表（PFI）由实验室开发，用于评估5个方面的自我报告功能：日常生活活动，日常生活工具活动，流动性和中度和剧烈活动。他们的目标是开发一种仪器，对整个生命周期的早期功能变化敏感，并能探测到个人随着年龄的增长如何改变他们的活动方式。该问卷已被用于研究不活跃的BLSA参与者，并将他们与活跃人群进行比较。在我们的许多参与者中，功能变化从50岁开始。早期的更改不是禁用的，但是需要修改一些活动的完成方式。在所有5个方面，部分活跃的BLSA参与者比完全活跃的参与者有更高的难度水平，但差异随着年龄的增长而增加，特别是在75岁以后。在IADL和ADL类别中观察到最大的差异。女性报告的难度相对较大，尤其是在依赖上身力量的活动中。我们目前正在努力缩短问卷，使其更易于管理和解释。研究正在进行中，以检查身体活动与身体功能（PFI）和死亡率的关系。目标是在可能的情况下确定身体活动的水平，以最大限度地减少功能限制和延长寿命。-身体活动心血管健康-人类受试者

Dr. Laura Talbot, Assistant Professor of Nursing, Johns Hopkins University has worked with us to examine what contribution physical activity has on cardiovascular fitness as estimated by VO2max. Based on currently accepted estimates of oxygen utilization for specific physical activities, the time Baltimore Longitudinal Study of Aging subjects spent doing 100 activities was converted to METS*minutes. METS is a standard way to express oxygen utilization that adjusts for body size. The 100 activities were then divided into three categories: low level activity (<4 METS), moderate level activity (4-6 METS), and high level activity (>6 METS). Univariate analysis found that cardiovascular fitness was significantly correlated with high level activity (r=.32), moderate level activity (r=.15), body size (BMI) (r=-.32), and age (r=- .58). In multivariate analysis with these variables, physical activity independently explained 1.6% of the variance in VO2max while sharing about 10% of the variance with age and BMI. Using the regression models, we estimate that for an average individual to increase there VO2max 10% requires 35-40 minutes a day of high level activity and 150 minutes a day of moderate level activity. These calculations support the general concept of the recent Surgeon General recommendations for daily physical activity. Currently, we are examining whether the level of cardivascular fitness or physical activity are risk factors for mortality. Cardiovascular fitness, as assesse by VO2max, is a strong independent contributor to both all cause and cardiac mortality. Physical activity is important, not to the same degree as fitness. The Physical Functioning Inventory (PFI) was developed by the laboratory to assesses self-reported functioning in 5 areas: Activities of Daily Living, Instrumental Activities of Daily Living, Mobility, and Moderate and Strenuous Activity. The goal was to develop an instrument that would be sensitive to early functional changes across the life span, and would detect how individuals modify how they do activities as they age. The questionnaire has been used to study inactive BLSA participants, and to compare them to the active population. Functional changes are found to begin by age 50 in many of our participants. The early changes are not disabling, but require modifications in how some activities are accomplished. In all 5 areas, partially active BLSA participants have higher levels of difficulty than fully active participants, but the difference increases with age, particularly after age 75. The largest differences were observed in the IADL and ADL categories. Women report relatively more difficulty, especially in activities dependent on upper body strength. We are currently working to shorten the questionnaire in order to make it easier to administer and to interpret.Studies are underway to examine the relationship of physical activity to physical functioning (PFI) and mortality. The goal is to define, where possible, the levels of physical activity required to minimize functional limitations and maximize longevity. - physical activity cardiovascular fitness - Human Subjects