Adherence to Self-Paced vs Prescribed Intensity PA: Exploring Mechanisms via EMA

描述（由申请人提供）：大约60%的美国人口超重或肥胖，肥胖与许多健康问题有关。建议超重和肥胖的成年人进行体育锻炼，以促进减肥和/或维持体重，并降低患慢性疾病的风险，包括心脏病、乳腺癌和结肠癌。尽管运动有很多好处，但只有20%的超重或肥胖成年人达到了国家建议的最低标准（每天30分钟，每周5天），而且在最初几个月的运动计划中退出的比例高达50%。鉴于这些数据，有必要加强对锻炼计划的坚持，尤其是对超重和肥胖的成年人。与流行的理论模型一致，运动促进干预通常侧重于认知（如自我效能）和社会（如社会支持）因素，但通常不针对情感过程。另一方面，享乐主义理论认为，行为的延续是由一个人对行为的感觉所引导的。与享乐理论一致，我们最近表明，在运动促进计划的基线上享受体育活动可以预测干预的成功。此外，最近对运动中的情感反应的研究表明，个别的中等强度运动（例如，快走）会导致超重和久坐不动的成年人产生急性的负面情感反应，这可能会使坚持运动变得更加困难。另外，当超重的成年人选择自己的步行速度时，会比规定特定的强度时产生更积极的情感反应。因此，在这项研究中，我们将在超重或肥胖人群中检查自定节奏步行与规定的中等强度步行对坚持六个月相同步行计划的影响。我们假设，与公共卫生指南中建议的中等强度的运动相比，建议超重的成年人进行自定节奏的强度运动（即更多的运动时间）会更好地坚持该计划。如果我们的假设得到证实，结果将为久坐、超重和肥胖的成年人提供未来的运动建议。此外，与享乐理论相一致，我们将利用生态瞬时评估（EMA，即电子日记）来探索运动的急性情感反应，作为坚持运动计划的预测因子。如果在参与者的自然环境中对运动的情感反应进行实时评估，显示出对步行计划的依从性，这将表明需要更多地关注健康行为模型中的情感变量，并将其作为健康促进干预的目标。公共卫生相关性：对于超重和肥胖的成年人来说，自定节奏的运动可能比规定的中等强度的运动（如快走）更令人愉快，更容易保持，从而导致更好的坚持，从而更好的健康结果。在这项研究中，我们将比较久坐、超重和肥胖的成年人对自定节奏运动和规定的中等强度运动的坚持率。我们还将要求参与者用手持电子日记对他们在每次锻炼期间的感受进行评分，以确定这些感受是否与坚持步行计划有关。

DESCRIPTION (provided by applicant): Approximately 60 percent of the U.S. population is overweight or obese, and obesity has been linked to numerous health problems. Physical activity has been recommended for overweight and obese adults to enhance weight- loss and/or weight-maintenance, and to reduce risk of chronic disease, including heart disease and cancers of the breast and colon. Despite the benefits of exercise, only 20 percent of overweight or obese adults meet the minimum national recommendations (30 min/day, 5 days/week), and drop out in the first few months of exercise programs is as high as 50 percent. Given these data, there is a need to improve adherence to exercise programs, especially for overweight and obese adults. Consistent with prevailing theoretical models, exercise promotion interventions typically focus on cognitive (e.g., self-efficacy) and social (e.g., social support) factors, but do not typically target affective processes. Alternatively, Hedonic Theory posits that continuation of a behavior is guided by how one feels as a consequence of performing the behavior. Consistent with Hedonic Theory, we have recently shown that enjoyment of physical activity at baseline of an exercise promotion program predicted intervention success. Moreover, recent research examining affective responses during exercise has shown that individual bouts of moderate intensity exercise (e.g., a brisk walk) can lead to acute negative affective responses among overweight and sedentary adults, potentially making exercise adherence more difficult. Alternatively, when overweight adults choose their own walking pace, it results in a more positive affective response than when a specific intensity is prescribed. Therefore, in this study we will examine the effects of self-paced walking compared to prescribed moderate intensity walking on adherence to otherwise identical, six-month walking programs among overweight or obese individuals. We hypothesize that recommending self-paced intensity exercise for overweight adults will result in better adherence to the program (i.e., more minutes of exercise) than prescribing exercise at moderate intensity, as recommended in public health guidelines. If our hypothesis is confirmed, the results will inform future exercise recommendations among sedentary, overweight and obese adults. Additionally, consistent with Hedonic Theory, we will explore acute affective responses to exercise as a predictor of adherence to the exercise program using ecological momentary assessment (EMA; i.e., electronic diaries). If affective responses to exercise, assessed in real time in participants' natural environments, are shown to predict adherence to the walking program, this will signal the need for greater attention to affective variables in health behavior models and as targets of health promotion interventions. PUBLIC HEALTH RELEVANCE: For overweight and obese adults, self-paced exercise may be more pleasurable and easier to maintain than exercise prescribed at moderate intensity (e.g., brisk walking), thus leading to better adherence and thereby better health outcomes. In this study we will compare adherence rates to self-paced exercise versus prescribed moderate intensity exercise among sedentary, overweight and obese adults. We will also ask participants to rate their feelings during each exercise session, using handheld electronic diaries, to determine whether these feelings are related to adherence to the walking program.