StandUPTV: Preparation and optimization phases of a mHealth intervention to reduce sedentary screen time in adults.

Recreational sedentary screen time (rSST) is the most prevalent sedentary behavior for adults outside of work, school, and sleep, and is strongly linked to poor health. StandUPTV is a mHealth trial that uses the Multiphase Optimization Strategy (MOST) framework to develop and evaluate the efficacy of three theory-based strategies for reducing rSST among adults. This paper describes the preparation and optimization phases of StandUPTV within the MOST framework. We identified three candidate components based on previous literature: (a) rSST electronic lockout (LOCKOUT), which restricts rSST through electronic means; (b) adaptive prompts (TEXT), which provides adaptive prompts based on rSST behaviors; and (c) earning rSST through increased moderate-vigorous physical activity (MVPA) participation (EARN). We also describe the mHealth iterative design process and the selection of an optimization objective. Finally, we describe the protocol of the optimization randomized controlled trial using a 23 factorial experimental design. We will enroll 240 individuals aged 23-64 y who engage in >3 h/day of rSST. All participants will receive a target to reduce rSST by 50% and be randomized to one of 8 combinations representing all components and component levels: LOCKOUT (yes vs. no), TEXT (yes vs. no), and EARN (yes vs. no). Results will support the selection of the components for the intervention package that meet the optimization objective and are acceptable to participants. The optimized intervention will be tested in a future evaluation randomized trial to examine reductions in rSST on health outcomes among adults.

An ecological momentary assessment study of affectively-charged motivational states and physical activity.

The physical activity (PA) intention-behavior gap has prompted researchers to explore other explanatory factors such as affective mechanisms which might better explain PA engagement. Affectively-charged motivations (e.g., desire, dread) are thought to influence the pursuit or avoidance of future behavior. This study examined whether affectively-charged motivations for PA changed across the day and were differentially associated with PA intensity. Participants (N = 60) wore ActiGraph GT3X accelerometers and answered EMA (M = 134.7 prompts/person) about affectively-charged motivations for upcoming PA using a 0-to-100-point scale (dread-excitement) in the morning, pre-activity, at-random, and evening for 14 days. Affectively-charged motivations for PA were lower in the morning and at-random compared to pre-activity (p = .004) and evening (p < .001). On average, individuals who rated morning affectively-charged motivations for PA 10-points higher engaged in 28 additional min/week of moderate-to-vigorous PA (p = .048). These findings suggest that affectively-charged motivations occurring in the morning may have greater salience for PA.

Effects of Increased Standing and Light-Intensity Physical Activity to Improve Postprandial Glucose in Sedentary Office Workers: Protocol for a Randomized Crossover Trial.

BACKGROUND: Prolonged bouts of sedentary time, independent from the time spent in engaging in physical activity, significantly increases cardiometabolic risk. Nonetheless, the modern workforce spends large, uninterrupted portions of the day seated at a desk. Previous research suggests-via improved cardiometabolic biomarkers-that this risk might be attenuated by simply disrupting sedentary time with brief breaks of standing or moving. However, this evidence is derived from acute, highly controlled laboratory experiments and thus has low external validity. OBJECTIVE: This study aims to investigate if similar or prolonged cardiometabolic changes are observed after a prolonged (2-week) practice of increased brief standing and moving behaviors in real-world office settings. METHODS: This randomized crossover trial, called the WorkWell Study, will compare the efficacy of two 2-week pilot intervention conditions designed to interrupt sitting time in sedentary office workers (N=15) to a control condition. The intervention conditions use a novel smartphone app to deliver real-time prompts to increase standing (STAND) or moving (MOVE) by an additional 6 minutes each hour during work. Our primary aim is to assess intervention-associated improvements to daily postprandial glucose using continuous glucose monitors. Our secondary aim is to determine whether the interventions successfully evoke substantive positional changes and light-intensity physical activity (LPA). Other outcomes include the feasibility and acceptability of the intervention conditions, fasting blood glucose concentration, femoral artery flow-mediated dilation (f-FMD), and systolic and diastolic blood pressure. RESULTS: The trial is ongoing at the time of submission. CONCLUSIONS: This study is a novel, randomized crossover trial designed to extend a laboratory-based controlled study design into the free-living environment. By using digital health technologies to monitor and prompt participants in real time, we will be able to rigorously test the effects of breaking up sedentary behavior over a longer period of time than is seen in traditional laboratory-based studies. Our innovative approach will leverage the strengths of highly controlled laboratory and free-living experiments to achieve maximal internal and external validity. The research team's multidisciplinary expertise allows for a broad range of biological measures to be sampled, providing robust results that will extend knowledge of both the acute and chronic real-life effects of increased standing and LPA in sedentary office workers. The WorkWell Study uses a rigorous transdisciplinary protocol that will contribute to a more comprehensive picture of the beneficial effects of breaking up sitting behavior. TRIAL REGISTRATION: ClinicalTrials.gov NCT04269070; https://clinicaltrials.gov/study/NCT04269070. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/45133.

Affective Response During Real-World Physical Activity as an Intervention Mediator.

Some people experience pleasure during physical activity, whereas it can be unpleasant for others. Modifying affective responses during physical activity in real-world situations may be an intervention strategy for increasing physical activity. This article follows an experimental medicine framework to summarize evidence identifying, assessing, and influencing affective response during real-world physical activity to inform interventions targeting this mediating mechanism.

Assessing basic and higher-level psychological needs satisfied through physical activity.

Background: There has been increasing interest in the extent to which the fulfillment of psychological needs is associated with physical activity engagement. However, a vast majority of studies consider only basic psychological needs such as relatedness, competence, and autonomy-with higher-level psychological needs such as challenge, creativity, and spirituality rarely being addressed. The aim of this study was to examine the preliminary reliability (i.e., internal consistency) and validity (i.e., discriminant, construct, and predictive) of a multi-dimensional scale to assess a range of basic and higher-level psychological needs satisfied through physical activity. Methods: A sample of 75 adults (ages 19-65 years, 59% female, 46% White) completed a baseline questionnaire measuring 13 psychological needs subscales (i.e., physical comfort, safety, social connection, esteem from others, individual esteem, learning, challenge, entertainment, novelty, creativity, mindfulness, aesthetic appreciation, and morality), exercise enjoyment, and exercise vitality. Participants then completed 14 days of accelerometer monitoring of physical activity and ecological momentary assessment of affective responses during physical activity sessions in daily life. Results: Internal consistency reliability was acceptable (>0.70) for all subscales except for mindfulness, aesthetic appreciation, and morality. Ten of the 13 subscales exhibited discriminant validity by differentiating between engagement (vs. no engagement) in at least one physical activity type (e.g., brisk walking and yoga/Pilates). All the subscales, except physical comfort and esteem from others, were associated with at least one of the construct validation criteria (e.g., exercise enjoyment, affective response during exercise). Five of the subscales were associated with at least one of the predictive validation criteria (i.e., light, moderate, vigorous intensity activity measured by accelerometer). Conclusion: Having the capacity to assess whether one's current physical activity is failing to fulfill various psychological needs-combined with recommendations about which types of activities may satisfy those needs-may address an important gap in physical activity promotion.