Comparing a recommendation for self-paced versus moderate intensity physical activity for midlife adults: an RCT

目前的USDHHS指南建议成年人每周在PA至少消耗1000千卡， 可通过每周150分钟中等强度PA，75分钟剧烈强度PA， 或者某种组合。然而，目前的估计表明，只有3.5%至43.5%的美国成年人和28%的 超重或肥胖的成年人遵守这些规定。13 -16此外，世界卫生组织所有成员国的人都遵守这些规定。 随着年龄的增长，组织区域变得不那么活跃。 50.15，18从本质上讲，PA率往往随着人们年龄的增长和体重的增加而下降，而PA的健康益处 变得更加明显。越来越多的研究表明，国家指导方针的转变， 强调自选强度的PA（即，自行调节）而不是规定的中等强度PA可以 导致更好地坚持PA计划，特别是超重和肥胖的中年人。 建议RCT，我们将进行一个基于现场的实验测试的假设，在超重和 肥胖中年（50-64岁）成人，当PA明确 建议自行调整节奏，而不是以中等强度开处方。这种方法代表了一种 对于那些开始PA新计划的人来说，这是一个重要的心态转变：也就是说，PA不需要是某种特定的 强度，以“计数”。如果发现自定进度的建议可使患者更好地遵守PA， 超重和肥胖的中年人，这可能会影响PA对该人群的建议。 目的1：我们将进行一项随机对照试验，比较自行起搏与规定的中等强度PA的效果 对低活动超重和肥胖中年（年龄50-64岁）成人（N=240）的PA行为。基于 所有参与者将接受为期12个月的干预，旨在帮助他们 克服常规PA的障碍。53自变量将随机分配到自定进度或 中度强度PA。主要结局为PA总量（频率x持续时间x 强度），如在第3、6、9和12个月通过加速度计测量的。H1：对自定进度PA的建议 将导致更多的PA（主要结局），相对于基于当前公众的处方中度强度PA 12，54 -56次要结果包括：（a）12个月内自我报告的PA分钟/周 程序，（B）健身变化，和（c）在第6个月和第12个月的体重变化。 目的2：使用EMA，我们将根据我们的概念模型检查治疗效果的假定介质 (see图1）中所示。H2：自定进度PA将导致更积极的情感反应（主要中介），因此 37次要媒介（类似于次要结果）将包括：（a） 感知的自主性，和（B）感知的努力（RPE）。37 PA行为的其他预测因素也将被探讨。

The current USDHHS guidelines recommend that adults expend at least 1000 kcal per week in PA,12 which can be obtained through 150 minutes per week of moderate intensity PA, 75 minutes of vigorous intensity PA, or some combination. However, current estimates suggest that only 3.5% to 43.5% of US adults, and 28% of overweight or obese adults adhere to these recommendations.13-16 Moreover, people across all World Health Organization regions become less active as they age.17 A more progressive decline in PA is seen after age 45- 50.15,18 In essence, PA rates tend to decrease as people age and gain weight while the health benefits of PA become more pronounced. A growing body of research19-36 suggests that a shift in national guidelines to emphasize PA of a self-selected intensity (i.e., self-paced) instead of prescribed moderate intensity PA may result in better adherence to PA programs, particularly among overweight and obese midlife adults.37,38 In the proposed RCT we will conduct a field-based experimental test of the hypothesis that, among overweight and obese midlife (ages 50-64) adults, adherence to PA programs will be improved when PA is explicitly recommended to be self-paced rather than prescribed at moderate intensity. This approach represents an important shift in mindset for those beginning a new program of PA: That is, PA need not be of a certain intensity in order to “count”. If a self-paced recommendation is found to lead to better PA adherence among overweight and obese midlife adults, this could have implications for PA recommendations for that population. Aim 1: We will conduct an RCT comparing the effects of self-paced versus prescribed moderate intensity PA on PA behavior among low-active overweight and obese midlife (ages 50-64) adults (N=240). Based on procedures developed in our pilot, all participants will receive a 12-month intervention designed to help them overcome barriers to regular PA.53 The independent variable will be random assignment to either self-paced or prescribed moderate intensity PA. The primary outcome will be total volume of PA (frequency x duration x intensity) as measured by accelerometry at months 3, 6, 9, and 12. H1: A recommendation for self-paced PA will result in more PA (primary outcome) relative to prescribing moderate intensity PA based on current public health guidelines.12,54-56 Secondary outcomes include: (a) self-reported min/week of PA over the 12-month program, (b) fitness changes, and (c) weight changes at months 6 and 12. Aim 2: Using EMA, we will examine putative mediators of treatment effects based on our conceptual model (see Figure 1). H2: Self-paced PA will lead to a more positive affective response (primary mediator) and thus greater increases in PA behavior.37 Secondary mediators (analogous to secondary outcomes) will include: (a) perceived autonomy, and (b) perceived exertion (RPE).37 Other predictors of PA behavior will also be explored.