Investigating the day-level associations between affective variability and physical activity using ecological momentary assessment.

BACKGROUND: Understanding affect as a determinant of physical activity has gained increased attention in health behavior research. Fluctuations in affect intensity from moment-to-moment (i.e., affective variability) may interfere with cognitive and regulatory processes, making it difficult to engage in goal-directed behaviors such as physical activity. Preliminary evidence indicates that those with greater trait-level affective variability engage in lower levels of habitual physical activity. However, the extent to which daily fluctuations in affect variability are associated with same-day physical activity levels is unknown. This study used ecological momentary assessment (EMA) to investigate day-level associations between affective variability (i.e., within-subject variance) and physical activity. METHODS: Young adults (N = 231, M = 23.58 ± 3.02 years) provided three months of smartphone-based EMA and smartwatch-based activity data. Every two weeks, participants completed a 4-day EMA measurement burst (M = 5.17 ± 1.28 bursts per participant). Bursts consisted of hourly randomly-prompted EMA surveys assessing momentary positive-activated (happy, energetic), positive-deactivated (relaxed), negative-activated (tense, stressed), and negative-deactivated (sad, fatigued) affect. Participants continuously wore a smartwatch to measure physical activity across the three months. Mixed-effects location scale modeling examined the day-level associations of affective variability (i.e., positive-activated, positive-deactivated, negative-activated, and negative-deactivated) and physical activity, controlling for covariates such as mean levels of affect, between-subject effects of physical activity, time of day, day of week, day in study, and smartwatch wear time. RESULTS: There were 41,546 completed EMA surveys (M = 182.22 ± 69.82 per participant) included in the analyses. Above and beyond mean levels of affect, greater day-level variability in positive-activated affect was associated with greater physical activity on that same day compared to other days (τ = 0.01, p < .001), whereas greater day-level variability in negative-deactivated affect was associated with less physical activity on that same day compared to other days (τ = -0.01, p < .001). Day-level variability in positive-deactivated affect or negative-activated affect were not associated with day-level physical activity (ps > .05) CONCLUSIONS: Individuals were less active on days with greater variability in feeling sad and fatigued but more active on days with greater variability in feeling happy and energetic. Understanding the dynamic relationships of affective variability with day-level physical activity can strengthen physical activity interventions by considering how these processes differ within individuals and unfold within the context of daily life. Future research should examine causal pathways between affective variability and physical activity across the day.

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.

Exploring the Effects of Perceived Stress on the Within-Person Relationships Between Daily Activity Levels and Sleep in Women: An Ecological Momentary Assessment Study.

BACKGROUND: Many studies show positive bidirectional associations between physical activity (PA) and sleep at the between-person level. There is an increased interest in investigating these associations at the within-person level. Few studies examined the effects of time-varying moderators on the within-person bidirectional associations between PA and sleep. This study aimed to examine the bidirectional within-person day-level associations between activity levels and self-reported sleep duration and explore the moderating effects of perceived stress on these day-level associations. METHOD: Data from 158 women that included 7-day free-living monitoring over 4 measurement periods was analyzed using multilevel modeling to explore the moderating effects of daily stress on the bidirectional, within-person associations between activity levels and self-reported sleep duration. Moderate-to-vigorous PA (MVPA) and sedentary behavior (SB) were estimated from a waist-worn accelerometer. Self-reported sleep duration and perceived stress were collected by ecological momentary assessment. RESULTS: No significant within-person associations between MVPA minutes and self-reported sleep duration were found in either direction. However, engaging in more MVPA than one's usual level was associated with longer sleep later that night when perceived stress was higher than usual (p = .04). Bidirectional negative within-person association between SB minutes and self-reported sleep duration was found (ps < .01). The negative association between SB and sleep duration later that night was stronger when perceived stress was lower than usual (p = .01). CONCLUSION: Daily stress played an important role in the day-to-day associations between activity levels and sleep.

Bidirectional Associations Between Physical Activity and Pain Among Older Adults: An Ecological Momentary Assessment Study.

This paper examines the within-day, bidirectional associations between physical activity and self-reported pain among older adults. Older adults (N = 104; range: 60-98 years) participated in a 10-day Ecological Momentary Assessment (EMA) study. Participants received six EMA prompts/day with a single item assessing pain. Participants wore an activPAL monitor measuring step counts. At the within-person level, on occasions when participants took more steps than usual in the 30 min before the EMA prompt, they were more likely to experience pain at the prompt (ß^02=0.0003, p < .03). At the between-person level, greater step counts in the 30 min before the EMA prompt, on average, were associated with less pain on occasions when pain was experienced (ß^01=-0.0005, p < .04). Pain was not related to subsequent stepping. Bidirectional associations between physical activity and pain were not documented, but physical activity did appear to be related to subsequent pain.

The ILHBN: challenges, opportunities, and solutions from harmonizing data under heterogeneous study designs, target populations, and measurement protocols.

The ILHBN is funded by the National Institutes of Health to collaboratively study the interactive dynamics of behavior, health, and the environment using Intensive Longitudinal Data (ILD) to (a) understand and intervene on behavior and health and (b) develop new analytic methods to innovate behavioral theories and interventions. The heterogenous study designs, populations, and measurement protocols adopted by the seven studies within the ILHBN created practical challenges, but also unprecedented opportunities to capitalize on data harmonization to provide comparable views of data from different studies, enhance the quality and utility of expensive and hard-won ILD, and amplify scientific yield. The purpose of this article is to provide a brief report of the challenges, opportunities, and solutions from some of the ILHBN's cross-study data harmonization efforts. We review the process through which harmonization challenges and opportunities motivated the development of tools and collection of metadata within the ILHBN. A variety of strategies have been adopted within the ILHBN to facilitate harmonization of ecological momentary assessment, location, accelerometer, and participant engagement data while preserving theory-driven heterogeneity and data privacy considerations. Several tools have been developed by the ILHBN to resolve challenges in integrating ILD across multiple data streams and time scales both within and across studies. Harmonization of distinct longitudinal measures, measurement tools, and sampling rates across studies is challenging, but also opens up new opportunities to address cross-cutting scientific themes of interest.

Health behavior changes, such as prevention of suicidal thoughts and behaviors, smoking, drug use, and alcohol use; and the promotion of mental health, sleep, and physical activities, and decreases in sedentary behavior, are difficult to sustain. The ILHBN is a cooperative agreement network funded jointly by seven participating units within the National Institutes of Health to collaboratively study how factors that occur in individuals' everyday life and in their natural environment influence the success of positive health behavior changes. This article discusses how information collected using smartphones, wearables, and other devices can provide helpful active and passive reflections of the participants' extent of risk and resources at the moment for an extended period of time. However, successful engagement and retention of participants also require tailored adaptations of study designs, measurement tools, measurement intervals, study span, and device choices that create hurdles in integrating (harmonizing) data from multiple studies. We describe some of the challenges, opportunities, and solutions that emerged from harmonizing intensive longitudinal data under heterogeneous study and participant characteristics within the ILHBN, and share some tools and recommendations to facilitate future data harmonization efforts.

Examining whether affectively-charged motivations predict subsequent affective response during physical activity: An ecological momentary assessment study.

Background: Evidence suggests positive affective response during physical activity increases the likelihood of engaging in and maintaining regular activity exercise in the future. Elucidating antecedents for a positive affective response may help identify intervention strategies to increase activity. Affectively-charged motivations (e.g., desires, urges, dreading) have been posited as proximal antecedents to physical activity but have yet to be examined in terms of their influence on affective response in real-world settings. The current study used ecological momentary assessment (EMA) to examine within-subject effects of pre-physical activity affectively-charged motivation on subsequent affective response during physical activity. Methods: Participants included 56 adults (M = 39.18 years, SD = 11.98; 67.86% female) who completed a 14-day smartphone-based EMA study. Prior to starting physical activity (time t), participants self-initiated an event-contingent EMA survey that assessed affectively-charged motivation for physical activity (i.e., rating scale from "dreading it" to "excited to do it"). EMA surveys prompted during subsequent physical activity (time t + 15 min) assessed affective response (i.e., feeling good-bad, energized-exhausted, thrilled-miserable, interested-bored, and relaxed-nervous). Multi-level linear regression models examined within-subject effects of pre- physical activity affectively-charged motivations on subsequent affective response during physical activity controlling for between-subjects effects of affectively-charged motivation, age, biological sex, time of day, and day of the week. Results: Overall, there were N = 304 physical activity occasions in the analysis (M = 5.43, SD = 3.97). When individuals reported more positive affectively-charged motivation for physical activity than usual before physical activity occasions, they reported feeling more energized (Estimate = 0.22, p < 0.001), good (Estimate = 0.25, p < 0.001), thrilled (Estimate = 0.12, p = 0.02), and interested (Estimate = 0.24, p < 0.001) during subsequent physical activity. Affectively-charged motivation was not associated with feeling more relaxed (Estimate = 0.11, p = 0.13) during subsequent physical activity. Conclusion: Momentary affectively-charged motivations predicted more positive affective response during subsequent physical activity among active adults. Future research can explore potential sources of intraindividual differences in affectively-charged motivations and further examine these associations with future physical activity behavior. To improve positive affective responses, interventions may boost affectively-charged motivations through real-time mobile prompting in naturalistic settings.

Children's Daily Negative Affect Patterns and Food Consumption on Weekends: An Ecological Momentary Assessment Study.

OBJECTIVE: This study evaluated the association between children's daily negative affect (NA) trajectories and unhealthy food consumption during weekends using ecological momentary assessment (EMA). DESIGN: Children answered mobile phone-based EMA surveys 7 times a day for 2 weekend days per wave, with each survey assessing current NA and past 2-hour consumption of fried foods (chips or fries), sweets (pastries or sweets), and sugary beverages (drank soda or energy drinks). SETTING: Los Angeles, California. PARTICIPANTS: The sample consisted of 195 children (51% female; mean age, 9.65 years; SD, 0.93) from the Mothers and Their Children's Health cohort study. MAIN OUTCOMES MEASURES: Negative affect trajectory (independent variable), unhealthy food consumption (dependent variable). ANALYSIS: Latent growth mixture modeling classified NA trajectories across days and examined their association with unhealthy food consumption. RESULTS: The latent growth mixture modeling identified 3 classes of daily NA trajectories: (1) stable low, (2) early increasing and late decreasing and (3) early decreasing and late increasing. Fried food consumption was higher on early increasing and late decreasing and early decreasing and late increasing NA trajectories than days with stable low NA. CONCLUSIONS AND IMPLICATIONS: By better understanding day-to-day variability in children's affect and eating, we can individually tailor obesity interventions to account for the emotional contexts in which unhealthy eating occurs.

Time-Varying Associations Between Device-Based and Ecological Momentary Assessment-Reported Sedentary Behaviors and the Concurrent Affective States Among Adolescents: Proof-of-Concept Study.

BACKGROUND: Previous studies on affective state-sedentary behavior (SB) associations have not accounted for their potentially time-varying nature and have used inconsistent SB measurement modalities. We investigated whether the strength of the associations between affective states and SB varied as a function of the time of day and by SB measurement modality (device-measured SB vs ecological momentary assessment-reported screen-based SB) in youth. OBJECTIVE: This study aimed to establish a proof of concept that SB-affective state associations may not be static during the day. In addition, we aimed to inform the methodology of future work, which may need to model associations as functions of the time of day and carefully consider how SB is operationalized or measured. METHODS: A total of 15 adolescents (age: mean 13.07, SD 1.03 years; 10/15, 67% female; 6/15, 40% Hispanic; 10/15, 67% healthy weight) wore thigh-mounted activPAL accelerometers and simultaneously reported their screen-based SBs and concurrent positive and negative affective states via ecological momentary assessment for 7 to 14 days (N=636 occasions). Time-varying effect models (varying slopes) examined how each measure of SB was associated with concurrent affective states from 7 AM to 8 PM. RESULTS: Time-varying effect model plots revealed that these associations varied in strength throughout the day. Specifically, device-based SB was related to greater concurrent negative affect only after approximately 5 PM and was unrelated to concurrent positive affect. Screen-based SB was related to greater concurrent negative affect only from 7 AM to approximately 9 AM. This was also related to greater concurrent positive affect from 7 AM to approximately 9:30 AM and from approximately 3 PM to approximately 7 PM. CONCLUSIONS: We provide preliminary evidence to suggest that future confirmatory studies investigating the SB-affective state relationship should consider the time-varying nature of these associations and SB measurement modality. There may be critical time windows when specific types of SBs co-occur with affect, suggesting that interventions may need tailoring to the time of day and type of SB if future studies using similar methodologies can replicate our findings.

Momentary intentions and perceived behavioral control are within-person predictors of sedentary leisure time: preliminary findings from an ecological momentary assessment study in adolescents.

Previous studies among adolescents conceptualize behavioral cognitions [e.g., intentions and perceived behavioral control (PBC)] as stable trait-like factors despite evidence suggesting they vary momentarily. We examined whether intentions and PBC momentarily relate to subsequent sedentary time during non-school periods. Healthy adolescents (N = 15, ages 11-15) reported their intentions and PBC regarding sedentary leisure behaviors via ecological momentary assessment (EMA) up to seven times/day for 14 days. Sedentary time in the two hours following each EMA prompt was measured by ActivPAL accelerometers. When participants reported greater sedentary intentions (within-person ß = 1.1, 95% CI 0.2, 2.1, p = 0.0213) and sedentary PBC (within-person ß = 1.7, 95% CI 0.6, 2.8, p = 0.0029), they accumulated greater sedentary time. This demonstrates that sedentary intentions and PBC are acutely associated with sedentary time among adolescents. Our findings highlight the potential for implementing just-in-time activity interventions among adolescents during at-risk periods within the day, characterized by deviations from one's usual intentions and PBC levels.

Associations among affect, diet, and activity and binge-eating severity using ecological momentary assessment in a non-clinical sample of middle-aged fathers.

PURPOSE: Knowledge of within-day factors associated with binge-eating severity among middle-aged fathers is limited. The purpose of the current report was to examine within-day associations of affect, diet, and activity in relation to binge-eating severity using ecological momentary assessment (EMA) in men. METHODS: Twenty-three middle-aged fathers completed 8 days of EMA and wore accelerometers to objectively assess activity. Generalized estimating equations assessed relationships among affect, diet, and activity and binge-eating severity. RESULTS: When positive affect was above average, men reported greater binge-eating severity in the next 2 h. Oppositely, when negative affect was above average, men reported less binge-eating severity in the next 2 h. At times when men reported consumption of sweets and fast food, they reported higher binge-eating severity during the same 2-h window. Men with greater average levels of light activity reported less overall binge-eating severity. CONCLUSIONS: Findings show that affect, unhealthy food intake, and light activity could be targeted among middle-aged fathers to reduce binge-eating severity and prevent eating disorders. LEVEL OF EVIDENCE: Level III: Evidence obtained from cohort or case-control analytic studies.

Transactional links between children daily emotions and internalizing symptoms: a six-wave ecological momentary assessment study.

BACKGROUND: This study explored the cross-sectional and longitudinal associations between everyday emotion dimensions and internalizing symptoms during the transition to early adolescence. We tested associations between children's intensity and instability of daily negative emotions (NE), positive emotions (PE), and daily NE differentiation (NED) with children's self-reported and their mothers' report of children's internalizing symptoms, across six waves, each wave separated by six months. METHODS: The sample included 199 ethnically diverse mother [Mage at baseline = 40.1 years (SD = 6.1] and child [Mage at baseline = 10.1 (SD = 0.90), 51% girls] dyads, who participated in six 7-day waves of ecological momentary assessment (EMA). During each wave, children reported on PE (i.e. happy and joyful) and NE (i.e. mad, sad, and stressed) up to eight random times per day through smartphone-based EMA. Children and mothers reported on children's internalizing symptoms at each wave. We used random-intercept cross-lagged panel models (RI-CLPMs) to test within- and between-person effects. RESULTS: At the within-person level, increased NE and decreased PE intensity, more unstable NE and PE, and decreased NED at any given wave were positively associated with children's self-reported internalizing symptoms but not with mother-reported child symptoms. However, emotion dimensions did not predict child-reported nor mother-reported child symptoms at the next wave. At the between-person level, higher average NE, more unstable PE and NE, and lower NED were positively associated with average child-reported and mother-reported child internalizing symptoms. CONCLUSIONS: This study suggests that emotional intensity, instability, and differentiation could be conceptualized as manifestations of internalizing symptoms but not as risk factors for its progression, or residual manifestations of it, among typical children.

Examining the day-level impact of physical activity on affect during the early months of the COVID-19 pandemic: An ecological momentary assessment study.

Engaging in physical activity (PA) may be a promising approach to mitigate the effects of the COVID-19 pandemic and related restrictions on daily affect. The study used ecological momentary assessment (EMA) to examine the within-subject associations of day-level PA with same-day evening affect. Interactions between daily PA and overall stress related to COVID-19 predicting evening affect were also examined. Adults living in the U.S. (N = 157, M age = 31.7, 84.1% female) participated in a 28-day smartphone-based EMA study during the early months of the pandemic (April - June 2020). Evening EMA surveys assessed daily PA minutes, momentary positive activated and deactivated affect, and momentary negative activated and deactivated affect. An online questionnaire assessed demographics. Multi-level linear regression models assessed day-level associations between PA and evening affect, controlling for age, sex, income, body mass index, employment status, and morning affect. There were N = 2,409 person-days in the analysis. Baseline COVID-19 stress was not associated with daily PA minutes (p = .09) or positive-activated affect (p = .14), but was associated with lower positive-deactivated affect (p < .001) and greater negative-activated and negative-deactivated affect (ps < .001) in the evenings. On days when individuals reported more PA than usual, they reported greater positive-activated and positive-deactivated affect, and lower negative-activated and negative-deactivated affect in the evening (ps < .001). The interaction of day-level PA and COVID-19 stress predicting evening positive-activated, positive-deactivated, negative-activated, and negative-deactivated affect was not significant (ps > .05). During the early months of the pandemic, adults experienced improved evening affect on days when they engaged in more PA. However, data did not show that PA counteracts detrimental effects of the COVID-19 pandemic on evening affect. Public health efforts should strategically promote and address barriers to PA during the pandemic.

Momentary associations between stress and physical activity among children using ecological momentary assessment.

Chronic and acute stress may have a detrimental effect on children's physical activity. Research on stress as a predictor of children's physical activity has mostly focused on stress between children, rather than how children's within-day variation in stress may predict physical activity. The current study assessed the within- and between-effects of stress on subsequent physical activity in three different time windows using ecological momentary assessment (EMA) and accelerometry. Children (N = 190; MBaseline Age =10.1±0.9, 53% female, 56% self-identified Hispanic/Latino) completed six semi-annual assessment bursts across three years. During each burst, participants responded to up to seven (weekend) or three (weekday) randomly prompted EMA surveys on smartphones for seven days and wore a waist-worn accelerometer. Multi-level structural equation modeling examined within- and between-subjects effects of stress as a predictor of children's subsequent moderate-to-vigorous physical activity (MVPA) in the 15, 30, and 60 minutes following the EMA prompt. Latent variables were created for within- and between-subjects stress were comprised of three EMA stress items. Higher than average levels of stress (within-subjects) significantly predicted lower MVPA in the subsequent 15, 30 and 60 minutes (ps < .05). Between-subjects stress was not significantly associated with subsequent MVPA (ps > .05). Results indicate that elevated momentary stress predicts less subsequent MVPA. These findings suggest that within-day fluctuations in stress may be a barrier for children engaging in physical activity. Childhood physical activity promotion and interventions should consider the role of children's stress, aim to reduce the stress children experience throughout the day, and incorporate stress coping strategies.

Ecological momentary assessment for health behaviors and contextual factors in persons with diabetes: A systematic review.

AIM: The objective of this systematic review was to summarize the ecological momentary assessment (EMA) methodology and associations between EMA-measured psychosocial, contextual factors and diabetes self-management. METHODS: The inclusion criteria were: research of EMA and diabetes self-management behaviors such as glucose checks, administration of insulin and eating-and dietary intake behaviors among persons with diabetes. A comprehensive search of several databases was conducted across all dates until July 2020. RESULTS: A modified Checklist for Reporting EMA Studies was used to assess the quality of studies. Among the ten included studies, participants were predominantly White adolescents with type 1 diabetes (T1D) and type 2 diabetes was studied in two studies. Time-varying, psychosocial contexts such as negative affect or negative social interaction were associated with missed insulin injection and poor adherence to glucose check. More preceding psychological stress was associated with more calorie intake from snacks or binge eating behaviors. Mornings were the most challenging time of day for adherence to diabetes self-management among adolescents with T1D. Intentional insulin withholding was more common in the afternoon in adults with T1D. CONCLUSIONS: EMA has potential clinical utility in the assessment of diabetes self-management and in the development of timely and individualized diabetes interventions.

Momentary and personal characteristics predicting maternal fruit and vegetable preparation for children using ecological momentary assessment.

A large body of literature on child-focused research regarding healthy eating within the family context has focused on behavioral management strategies, such as reinforcement, or parental modeling through personal intake or encouragement. However, food preparation behaviors among mothers have been understudied. Also unknown is how maternal food preparation behaviors vary across population subgroups and contexts. The study objective was to elucidate momentary characteristics (i.e., time of day, weekday, and family meals) and personal characteristics (i.e., ethnicity, working status, household characteristics, body mass index, income, and child's age) associated with maternal fruit and vegetable (F/V) preparation through ecological momentary assessment (EMA). 186 mothers (Mage = 40.81) of children (Mage = 9.61, 49.5% female) completed six semi-annual waves, each lasting seven days. Mothers completed up to eight EMA surveys a day, which assessed family meals and F/V preparation, and reported personal characteristics through paper questionnaires. Multilevel generalized estimating equations examined the likelihood of F/V preparation. Momentary, within-day characteristics (i.e., occurrence of family meals, weekdays, afternoons) were associated with greater likelihood of mothers' fresh F/V preparation (ps < 0.05). Additionally, personal characteristics such as non-Hispanic ethnicity, not working full-time, having a child aged six months to five years in the household, and lower child BMI-z were associated with greater fresh F/V preparation among mothers (ps < 0.05). Findings may inform family-based obesity and nutrition intervention programs by understanding which families and in what contexts mothers are more likely to prepare F/Vs.

Social and Physical Context Moderates Older Adults' Affective Responses to Sedentary Behavior: An Ecological Momentary Assessment Study.

OBJECTIVES: Older adults engage in excessive sedentary behaviors which hold significant health implications. Examining affect responses during sedentary behavior is not well understood despite the wealth of evidence linking affect and motivation. Contextual influences (i.e., social and physical) likely influence affective responses during sedentary behavior and therefore warrant further investigation. METHOD: Older adults (n = 103, Mage = 72, range: 60-98) participated in a 10-day study where they received 6 randomly timed, smartphone-based Ecological Momentary Assessment (EMA) prompts/day. Participants reported their affect, current behavior, and context at each EMA prompt. Participants also wore an activPAL accelerometer to measure their sedentary behavior duration. Separate multilevel models examined the extent to which the context influences affective responses during self-report sedentary (vs nonsedentary) behaviors. RESULTS: The social context moderated the association between sedentary behavior and negative affect. The physical context moderated the association between sedentary behavior and positive affect. DISCUSSION: Interventions should consider the context of behaviors when designing interventions to reduce sedentary behavior as some contextual factors may attenuate, while other contexts may exacerbate, associations between activity-related behaviors and indicators of well-being.

Age-varying Bi-directional Associations Between Momentary Affect and Movement Behaviors in Children: Evidence From a Multi-wave Ecological Momentary Assessment Study.

BACKGROUND: The bi-directional associations between affective states and movement behaviors (e.g., physical activity, sedentary behavior) have been observed in children. It is unclear if the strength of these bi-directional associations varies with age as children transition from childhood to adolescence. PURPOSE: This multi-wave ecological momentary assessment (EMA) study investigates the acute time-varying associations between affect and movement behaviors among youth. METHODS: Children (N = 195, baseline mean age = 10.72, range = 8-12 years, mean BMI-z = 0.49, 51% female) participated in a six-wave EMA study across three years. Each EMA survey captured momentary positive and negative affect. Time spent in moderate-to-vigorous physical activity (MVPA) and sedentary time in the 15-min window before and after each EMA survey was calculated using accelerometry data. Time-varying effect models (TVEM) examined the acute bi-directional associations between momentary positive/negative affect and MVPA/sedentary time across ages 8 to 14. RESULTS: Children provided 14,246 valid activity-matched EMA surveys across all waves. TVEM plots revealed that the directionality and the strength (time-varying slopes) of associations between momentary affect and activity levels vary across ages. Positive affect was associated with higher MVPA levels and lower sedentary time at younger ages, whereas negative affect linked to lower MVPA levels and more sedentary time at older ages. CONCLUSIONS: The acute associations between momentary affect and (in)activity levels may vary as a function of children's age. Applying TVEM to intensive longitudinal data could provide valuable information for developing age-tailored interventions that promote healthy lifestyles among children and adolescents.

The influence of context stability on physical activity and sedentary behaviour habit and behaviour: An ecological momentary assessment study.

OBJECTIVES: This study used ecological momentary assessment (EMA) to empirically test the theoretical propositions that habit for and level of physical activity (PA) and sedentary behaviour (SB) should be associated with degree of context stability of those behaviours. DESIGN: Older adults (N = 104) completed a 10-day EMA protocol and continuous accelerometer monitoring. METHODS: As part of the EMA protocol older adults answered 6 EMA prompts per day to assess current behaviour as well as social and physical contexts of behaviour. Temporal context was determined via time stamps of EMA questionnaires. Context stability was calculated as the reversed entropy scores of the contexts (physical, social, temporal, behavioural [i.e., type]) of PA and SB weighted for total frequency of context prompts. Habit for PA and SB (operationalized as self-reported behavioural automaticity) was assessed via baseline questionnaire. An ActivPAL monitor was worn to assess average daily time spent in moderate-vigorous PA (MVPA), light PA, and SB, and number of sit-to-stand transitions. RESULTS: More stable physical contexts for physical activity predicted more MVPA (ß = 10.22) and more stable social contexts for sitting predicted more SB (ß = 1.36). More variety of time people tended to report engaging in SB, the more SB engaged in (ß = -13.76). No context stability scores predicted light PA, sit-to-stand transitions, or habit. CONCLUSIONS: Although context stability was related to behaviour, this did not appear to be explained by habit, as habit did not differ by the degree of context stability surrounding bouts of PA or SB.

Acute Bidirectional Relations Between Affect, Physical Feeling States, and Activity-Related Behaviors Among Older Adults: An Ecological Momentary Assessment Study.

BACKGROUND: The majority of older adults are physically inactive; therefore, strategies are needed to effectively promote sustained engagement in physical activity. PURPOSE: This study was designed to investigate acute bidirectional relationships between affective and physical feeling states and activity-related behaviors among older adults in the context of everyday life using Ecological Momentary Assessment (EMA). METHODS: Older adults (n = 103, Mage = 72, Range: 60-98) participated in a 10-day study where they completed up to 6 smartphone-based EMA prompts/day. At each EMA prompt, participants reported their current positive and negative affect and physical feeling states. Participants wore an activPAL accelerometer to measure time spent standing and time spent stepping before and after the prompt. Separate multilevel random coefficient linear and logistic regression models examined these bidirectional relationships. RESULTS: On occasions when older adults engaged in more standing and more stepping than was typical for them in the 15 and 30 min prior to the EMA prompt, they tended to report greater feelings of energy at the prompt. On occasions when older adults reported greater feelings of energy than was typical for them, they engaged in more standing and more stepping in the 15 and 30 min following the EMA prompt. Positive and negative affect was unrelated to activity-related behaviors. CONCLUSIONS: Feelings of energy appear to be strongly linked to activity-related behaviors in older adults; however, this was not the case for positive or negative affect. These findings may have implications for optimal delivery of just-in-time intervention context based on affective states or current behaviors.

Real-Time Data Collection to Examine Relations Between Physical Activity and Affect in Adults With Mental Illness.

Adults with serious mental illness engage in limited physical activity, which contributes to significant health disparities. This study explored the use of both ecological momentary assessments (EMAs) and activity trackers in adults with serious mental illness to examine the bidirectional relationship between activity and affect with multilevel modeling. Affective states were assessed up to seven times per day using EMA across 4 days. The participants (n = 20) were equipped with a waist-worn accelerometer to measure moderate to vigorous physical activity. The participants had a mean EMA compliance rate of 88.3%, and over 90% of completed EMAs were matched with 30-min windows of accelerometer wear. The participants who reported more positive affect than others had a higher probability of engaging in moderate to vigorous physical activity. Engaging in more moderate to vigorous physical activity than one's usual was associated with more negative affect. This study begins to address the effect of momentary mood on physical activity in a population of adults that is typically difficult to reach.