Intraday relations between physical activity and energy intake among behavioral weight loss participants.

OBJECTIVE: Weight loss results from a negative energy balance, when energy intake (EI) is less than energy expended, e.g., from physical activity (PA). However, PA may impact energy balance beyond energy expenditure alone, through indirect effects on eating behavior. Yet, no research has examined if engaging in PA-a central component of most weight loss programs-is associated with same-day EI among individuals with overweight/obesity pursuing weight loss. METHOD: Adults (N = 101) with overweight/obesity in a weight loss program were prescribed a reduced-calorie diet and PA regimen (250 min of moderate-to-vigorous PA at midtreatment). For 3 weeks at midtreatment, PA and EI were measured via an accelerometer and self-monitoring app, respectively. Multilevel models examined within-person relations between PA and EI preceding PA ("pre-PA"), acutely following PA ("acute post-PA," the 2 hr following PA), in the time following the acute post-PA period ("remaining time in day"), and across entire PA days ("full-day"), relative to non-PA matched time periods. RESULTS: EI was higher in the pre-PA and acute post-PA periods. There were no reliable differences in EI during the remaining time in day nor across the full-day on PA days versus within-subject matched non-PA days. There also was insufficient evidence to suggest EI pre-PA, post-PA, or across entire PA days, relative to non-PA matched time periods, was associated with percent weight change. CONCLUSIONS: Findings suggest that engaging in PA was associated with different within-person EI patterns compared to non-PA days, though there was little evidence to support that these patterns relate to weight change. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Affective responses during physical activity predicting same day and next day physical activity in emerging adulthood: an Ecological Momentary Assessment study.

OBJECTIVES: The purpose of the current study was to examine how affective responses during physical activity (PA) captured in real-time and real-world settings via Ecological Momentary Assessment (EMA) predicted same day and next day physical activity. METHODS AND MEASURES: During a 10-day study, physically active participants wore an accelerometer which captured PA and triggered EMA prompts during PA to capture affect (e.g. positive, negative). Additional EMA prompts captured affect during non-PA. RESULTS: Emerging adults (n = 80; Mage = 22.8; MBMI = 25.3; 56% White, 79% Female) completed the study. On days when emerging adults experienced an increase in their average feelings of energy during PA compared to non-PA occasions, they tended to engage in more PA the same day. On days when emerging adults experienced an increase in their average feelings of fatigue during PA compared to non-PA occasions, they tended to engage in less PA the next day. Positive and negative affect during PA, compared to non-PA, was not associated with same or next day PA. CONCLUSIONS: There is inconsistent evidence that affective responses during PA can predict same day and next day PA. Future work should examine the affect-physical activity link among those who are insufficiently active and across person-specific micro-timescales.

Screen-based and non-screen-based sedentary behaviors are differentially associated with affective states in older adults.

Excessive sedentary behavior (SB) contributes to poor affective and physical feeling states, which is particularly concerning for older adults who are the most sedentary sector of the population. Specific types of SB have been shown to differentially impact health in cross-sectional and longitudinal studies, with screen-based SB more negatively impacting aspects of mental health. This study used Ecological Momentary Assessment (EMA), a real-time, intensive longitudinal data capture methodology, to examine the differential impact of screen-based behaviors on momentary affective responses during SB in naturalistic settings. A diverse sample of older adults (pooled across 2 studies) completed an EMA protocol for 8-10 days with six randomly delivered, smartphone assessments per day. At each EMA prompt, participants reported their current activity, whether they were sitting while doing that activity, and affective states. Multilevel models assessed whether screen-based (vs. non-screen-based) behavior moderated affective response during SB. At the within-person level, older adults experienced less positive affect during SB when engaged in a screen-based behavior compared to a non-screen-based SB (B = -0.10, p < 0.01). At the between-person level, positive associations between SB and negative affect (B = 0.79, p = 0.03) were stronger if participants reported engaging in screen-based behaviors for a greater proportion of prompts. Among older adults, screen-based SB may lead to poorer affective states compared to non-screen-based SB. Interventions aiming to reduce SB in this population should consider targeting reductions in screen-based SB as means to improve affective states.

Studying Movement-Related Behavioral Maintenance and Adoption in Real Time: Protocol for an Intensive Ecological Momentary Assessment Study Among Older Adults.

BACKGROUND: Older adults struggle to maintain newly initiated levels of physical activity (PA) or sedentary behavior (SB) and often regress to baseline levels over time. This is partly because health behavior theories that inform interventions rarely address how the changing contexts of daily life influence the processes regulating PA and SB or how those processes differ across the behavior change continuum. Few studies have focused on motivational processes that regulate the dynamic nature of PA and SB adoption and maintenance on microtimescales (ie, across minutes, hours, or days). OBJECTIVE: The overarching goal of Project Studying Maintenance and Adoption in Real Time (SMART) is to determine the motivational processes that regulate behavioral adoption versus maintenance over microtimescales, using a dual process framework combined with ecological momentary assessment and sensor-based monitoring of behavior. This paper describes the recruitment, enrollment, data collection, and analytics protocols for Project SMART. METHODS: In Project SMART, older adults engaging in at least 30 minutes of moderate-to-vigorous intensity PA per week complete 3 data collection periods over 1 year, with each data collection period lasting 14 days. Across each data collection period, participants wear an ActiGraph GT3X accelerometer (ActiGraph, LLC) on their nondominant waist and an ActivPAL micro4 accelerometer (PAL Technologies, Ltd) on their anterior thigh to measure PA and SB, respectively. Ecological momentary assessment questionnaires are randomly delivered via smartphone 10 times per day on 4 selected days in each data collection period and assess reflective processes (eg, evaluating one's efficacy and exerting self-control) and reactive processes (eg, contextual cues) within the dual process framework. At the beginning and end of each data collection period, participants complete a computer-based questionnaire to learn more about their typical motivation for PA and SB, physical and mental health, and life events over the course of the study. RESULTS: Recruitment and enrollment began in January 2021; enrollment in the first data collection period was completed by February 2022; and all participants completed their second and third data collection by July 2022 and December 2022, respectively. Data were collected from 202 older adults during the first data collection period, with approximate retention rates of 90.1% (n=182) during the second data collection period and 88.1% (n=178) during the third data collection period. Multilevel models and mixed-effects location scale modeling will be used to evaluate the study aims. CONCLUSIONS: Project SMART seeks to predict and model the adoption and maintenance of optimal levels of PA and SB among older adults. In turn, this will inform the future delivery of personalized intervention content under conditions where the content will be most effective to promote sustained behavior change among older adults. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47320.

Investigating Intraindividual Variability of Psychological Needs Satisfaction and Relations With Subsequent Physical Activity.

Heeding recent calls to capture dynamic variability of physical activity (PA) motivation within a self-determination theory framework, this study examined the extent to which psychological needs satisfaction in PA predicted subsequent PA, disaggregating within-person and between-persons data. University students (N = 89) wore an ActiGraph GT3X accelerometer for 6 days and reported basic psychological needs satisfaction daily. Multilevel models examined whether competence, autonomy, and relatedness for the previous day's PA (>2,020 counts per minute) predicted the following day's minutes of PA (>2,020 counts per minute), controlling for previous-day PA. Participants who, on average, reported greater feelings of autonomy and competence tended to engage in more minutes of PA the following day. When participants reported feeling greater relatedness than what was typical for them, they tended to engage in more PA the following day. Psychological needs vary day to day, but how and to what extent they predict PA depends on the specific need.

Associations Between Social Cognitive Determinants and Movement-Related Behaviors in Studies Using Ecological Momentary Assessment Methods: Systematic Review.

BACKGROUND: The social cognitive framework is a long-standing framework within physical activity promotion literature to explain and predict movement-related behaviors. However, applications of the social cognitive framework to explain and predict movement-related behaviors have typically examined the relationships between determinants and behavior across macrotimescales (eg, weeks and months). There is more recent evidence suggesting that movement-related behaviors and their social cognitive determinants (eg, self-efficacy and intentions) change across microtimescales (eg, hours and days). Therefore, efforts have been devoted to examining the relationship between social cognitive determinants and movement-related behaviors across microtimescales. Ecological momentary assessment (EMA) is a growing methodology that can capture movement-related behaviors and social cognitive determinants as they change across microtimescales. OBJECTIVE: The objective of this systematic review was to summarize evidence from EMA studies examining associations between social cognitive determinants and movement-related behaviors (ie, physical activity and sedentary behavior). METHODS: Studies were included if they quantitatively tested such an association at the momentary or day level and excluded if they were an active intervention. Using keyword searches, articles were identified across the PubMed, SPORTDiscus, and PsycINFO databases. Articles were first assessed through abstract and title screening followed by full-text review. Each article was screened independently by 2 reviewers. For eligible articles, data regarding study design, associations between social cognitive determinants and movement-related behaviors, and study quality (ie, Methodological Quality Questionnaire and Checklist for Reporting Ecological Momentary Assessment Studies) were extracted. At least 4 articles were required to draw a conclusion regarding the overall associations between a social cognitive determinant and movement-related behavior. For the social cognitive determinants in which a conclusion regarding an overall association could be drawn, 60% of the articles needed to document a similar association (ie, positive, negative, or null) to conclude that the association existed in a particular direction. RESULTS: A total of 24 articles including 1891 participants were eligible for the review. At the day level, intentions and self-efficacy were positively associated with physical activity. No other associations could be determined because of conflicting findings or the small number of studies investigating associations. CONCLUSIONS: Future research would benefit from validating EMA assessments of social cognitive determinants and systematically investigating associations across different operationalizations of key constructs. Despite the only recent emergence of EMA to understand social cognitive determinants of movement-related behaviors, the findings indicate that daily intentions and self-efficacy play an important role in regulating physical activity in everyday life. TRIAL REGISTRATION: PROSPERO CRD42022328500; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=328500.

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.

Bidirectional Relations Between Daily Stress and Sleep Among Black Emerging Adults.

BACKGROUND: Black adults experience higher levels of stress and more dysfunctional sleep patterns compared to their White peers, both of which may contribute to racial disparities in chronic health conditions. Dysfunctional sleep patterns are also more likely in emerging adults compared to other age groups. Daily stress-sleep relations in Black emerging adults are understudied. PURPOSE: This study used ecological momentary assessment (EMA) and wrist-worn actigraphy to examine bidirectional associations between daily stress and sleep among Black emerging adults. METHODS: Black college freshmen (N = 50) completed an EMA protocol (i.e., five EMA prompts/day) and wore an accelerometer for 7 days. The first EMA prompt of each day assessed sleep duration and quality. All EMA prompts assessed stress. Wrist-worn actigraphy assessed nocturnal sleep duration, sleep onset latency, sleep efficiency, and waking after sleep onset. RESULTS: At the within-person level, stress experienced on a given day was not associated with any sleep metrics that night (p > .05). On evenings when actigraphy-based sleep duration was shorter (B = -0.02, p = .01) and self-reported sleep quality was poorer (B = -0.12, p = .02) than usual, stress was greater the following day. At the between-person level, negative bidirectional relations existed between stress and actigraphy-based waking after sleep onset (stress predicting sleep: B = -0.35, p = .02; sleep predicting stress: B = -0.27, p = .04). CONCLUSIONS: Among Black emerging adults, associations between daily sleep and stress vary at the between- and within-person level and are dependent upon the sleep metric assessed. Future research should compare these relations across different measures of stress and different racial/ethnic groups to better understand health disparities.

Temporal stability of behavior, temporal cue-behavior associations, and physical activity habit strength among mothers with school-aged children.

Objective: PA habits reflect stable, consistent patterns in behaviours that are performed automatically in response to temporal or contextual cues. Mothers face multiple demands and complex schedules related to parenting. This study examined how subject-level mean, variability, and slopes in device-measured moderate-to-vigorous physical activity (MVPA) over three different timescales were associated with mothers' PA habits. Methods and Measures: Mothers (n = 125; Mage=41.4 years) completed six measurement periods across three years. Each measurement period consisted of seven days of accelerometry. MVPA minutes were processed across hours, days, and measurement periods. PA habits were assessed in the last measurement period. Results: Subject-level means of MVPA at all timescales were positively associated with stronger PA habits (ßs = 0.42-0.48, ps<.01). Subject-level variability in day-level MVPA was positively associated with habits (ß = 0.39, p=.01). Furthermore, mothers who engaged in higher mean day-level MVPA had a more positive association between subject-level variability in day-level MVPA and habit strength compared to mothers with lower mean day-level MVPA overall (ß = 0.28, p=.04). Mothers who had steeper increases in MVPA across measurement periods (i.e. subject-level slope) reported stronger habits (ß = 0.43; p = 0.03). Conclusion: Flexibly adjusting daily PA levels may be a necessary strategy to maintain habits in the face of parenting demands.

Within-person examination of the exercise intention-behavior gap among women in midlife with elevated cardiovascular disease risk.

Engaging in moderate-to-vigorous intensity physical activity (MVPA) is important for protecting cardiovascular health among women in midlife (i.e., ages 40-60), particularly if they have already developed conditions that increase their risk for cardiovascular disease (e.g., hypertension). Although the gap between MVPA intentions and behavior is well documented in other populations, little is known about the intention-behavior gap in this at-risk group - particularly as it plays a role in daily life. The present study employed an ecological momentary assessment design to examine the relation between women's MVPA intentions and behavior in the subsequent 3 hours, as well as momentary moderators of this relation (i.e., affective states and body satisfaction). Surveys sent to women's smartphones 5 times per day for 10 days while they wore ActiGraph GT3X waistband accelerometers. Women achieved their exercise intentions at only 13% of occasions on which they set intentions. Although the most common intended exercise was walking, women engaged in more minutes of MVPA after setting intentions to do yoga or Pilates than any other type of exercise (sr = 0.25). Multilevel models showed a modest within-person relation between minutes of intended MVPA and observed MVPA in the next 3 hours (sr = 0.20). This relation was moderated within-person by the reported extent of positive affect (particularly contentment) and body satisfaction (srs = 0.35 and 0.28, respectively). Findings extend knowledge about the physical activity intention-behavior gap to an at-risk population of women and identify positive affect and body satisfaction as potential contextual influences for this group, which could inform improvements to existing interventions (e.g., delivering intervention content at times with lower-than-usual body satisfaction).

Low-Income, Older African Americans' Engagement in and Perceptions of a Smartphone-Based Ecological Momentary Assessment Study of Physical Activity and Sedentary Behavior.

BACKGROUND AND OBJECTIVES: Smartphone-based ecological momentary assessment (EMA) methods can provide novel insights into modeling and predicting activity-related behaviors, yet many racial and ethnic minority groups report barriers to participating in mobile health research. We aim to (a) report on strategies used to successfully recruit and retain minority older adults in a smartphone-based physical activity and sedentary behavior EMA study and (b) report on participants' perceptions of study acceptability. RESEARCH DESIGN AND METHODS: Researchers partnered with trusted individuals and community organizations serving older adults to facilitate recruitment for an 8-day EMA study of minority older adults' physical activity and sedentary behavior. Additional strategies such as having experienced, culturally competent team members and available technical support were employed to further recruitment and retention efforts. A poststudy questionnaire assessed participants' perceptions of study acceptability. RESULTS: In total, 123 minority older adults were recruited, 102 met inclusion criteria, 91 completed the study, and 89 completed the poststudy questionnaire. The sample consisted of predominantly low-income African American women with an average age of 70 years. Responses to open-ended questions revealed that the most enjoyable aspects of study participation were the ability to learn more about themselves, contribute to science and/or their community, engage in a new activity, and receive financial compensation. Participants reported the least enjoyable aspects of the study included the frequency of EMA questionnaires, apprehension of missing EMA questionnaires, carrying the smartphone, and difficulty wearing the accelerometer. Most participants (97%) expressed interest in being contacted for future studies. DISCUSSION AND IMPLICATIONS: Low-income, older African Americans reported positive perceptions of a smartphone-based EMA study of physical activity and sedentary behavior. Findings suggest that applying demonstrated strategies to engage this population in technology-based health research can enhance recruitment and retention efforts; however, it is unclear which strategies are most effective in reducing participation barriers.

Adolescents' sedentary time, affect, and contextual factors: An ecological momentary assessment study.

BACKGROUND: Few adolescents achieve sufficient levels of physical activity, and many are spending most of their time in sedentary behavior. Affective response following sedentary time may influence motivation to remain sedentary. Ecological Momentary Assessment (EMA) is a real-time data capture methodology that can be used to identify factors influencing sedentary time, such as the context of the home setting, and resulting affective state within a free-living setting. The purpose of this study was to evaluate the relationship between context at home and adolescent sedentary time, and the relationship of sedentary time and subsequent affect. METHODS: Adolescents (n = 284; 10-16 y) participated in an EMA study that used random, interval-based sampling methods. Adolescents each received 22 unannounced surveys over 7-days through a smartphone application. One survey was randomly sent within each 2-h time-period. These time-periods occurred between 4:00 pm-8:00 pm on weekdays and 8:00 am-8:00 pm on the weekend. This 15-question survey included a series of questions on context (indoors/outdoors, alone/not alone) and positive affect. Adolescents concurrently wore an accelerometer at the hip, and the 30-min bout of accelerometry data prior to each survey was used in analyses. Mixed-effect location scale models were used to examine the association between context at home and sedentary time (stage 1) and the adjusted sedentary time and positive affect (stage 2), with each model adjusted for covariates. RESULTS: Adolescents were 12.6 ± 1.9 y of age on average, about half were White (58%), and engaged in high levels of sedentary behavior during the 30 min prior to the survey (21.4 ± 6.8 min). Most surveys occurred when adolescents were with others (59%) and indoors (88%). In Stage 1, both being alone and being indoors at home were positively associated with sedentary time (p <  0.001 for both). In Stage 2, adjusted sedentary time was not related to positive affect. Age was negatively related to positive affect (p <  0.001). CONCLUSIONS: Both contextual factors, being alone and indoors at home, were related to additional time spent sedentary compared to being with someone or outdoors. After adjustment, sedentary time was not related to subsequent positive affect, indicating other factors may be related to adolescent's positive affect in home settings.

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.

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.

Physical activity is positively associated with college students' positive affect regardless of stressful life events during the COVID-19 pandemic.

The study was designed to determine associations between physical activity (PA) and affect before and during COVID-19 stay-at-home orders and how change in PA predicted change in affect during this time. Before and during COVID-19 stay-at-home orders, college students (n = 107) completed assessments of PA, positive and negative affect, sleep quality, food insecurity, and stressful life events (during stay-at-home order only). Total minutes of PA was positively associated with positive affect before (B = 0.01, p < 0.01) and during (B = 0.01, p = 0.01) COVID-19 stay-at-home orders. Change in minutes of PA was positively associated with change in positive affect (B = 0.01, p = 0.01). Associations between PA and positive affect were not moderated by stressful life events. PA only predicted negative affect before COVID-19 stay-at-home orders (B = -0.003, p = 0.04). PA appears to enhance positive affect during a global pandemic. Findings have implications for PA as a tool for maintaining or enhancing mental health during a time of trauma and uncertainty.

An empirical example of analysis using a two-stage modeling approach: within-subject association of outdoor context and physical activity predicts future daily physical activity levels.

People differ from each other to the extent to which momentary factors, such as context, mood, and cognitions, influence momentary health behaviors. However, statistical models to date are limited in their ability to test whether the association between two momentary variables (i.e., subject-level slopes) predicts a subject-level outcome. This study demonstrates a novel two-stage statistical modeling strategy that is capable of testing whether subject-level slopes between two momentary variables predict subject-level outcomes. An empirical case study application is presented to examine whether there are differences in momentary moderate-to-vigorous physical activity (MVPA) levels between the outdoor and indoor context in adults and whether these momentary differences predict mean daily MVPA levels 6 months later. One hundred and eight adults from a multiwave longitudinal study provided 4 days of ecological momentary assessment (during baseline) and accelerometry data (both at baseline and 6 month follow-up). Multilevel data were analyzed using an open-source program (MixWILD) to test whether momentary strength between outdoor context and MVPA during baseline was associated with average daily MVPA levels measured 6 months later. During baseline, momentary MVPA levels were higher in outdoor contexts as compared to indoor contexts (b = 0.07, p < .001). Participants who had more momentary MVPA when outdoors (vs. indoors) during baseline (i.e., a greater subject-level slope) had higher daily MVPA at the 6 month follow-up (b = 0.09, p < .05). This empirical example shows that the subject-level momentary association between specific context (i.e., outdoors) and health behavior (i.e., physical activity) may contribute to overall engagement in that behavior in the future. The demonstrated two-stage modeling approach has extensive applications in behavioral medicine to analyze intensive longitudinal data collected from wearable sensors and mobile devices.

Influence of Nutrient Intake on 24 Hour Urinary Hydration Biomarkers Using a Clustering-Based Approach.

Previous work focusing on understanding nutrient intake and its association with total body water homeostasis neglects to consider the collinearity of types of nutrients consumed and subsequent associations with hydration biomarkers. Therefore, the purpose of this study was to analyze consumption patterns of 23 a priori selected nutrients involved in osmotic homeostasis, as well as their association with 24 h urinary hydration markers among fifty African-American first-year college students through a repeated measures observation in a daily living setting. Through application of hierarchical clustering, we were able to identity four clusters of nutrients based on 24 h dietary recalls: (1) alcohol + pinitol, (2) water + calcium + magnesium + erythritol + inositol + sorbitol + xylitol, (3) total calories + total fat + total protein + potassium + sodium + zinc + phosphorous + arginine, and (4) total carbohydrates + total fiber + soluble fiber + insoluble fiber + mannitol + betaine. Furthermore, we found that consumption of nutrients in Cluster #2 was significantly predictive of urine osmolality (p = 0.004); no other clusters showed statistically significant associations with 24 h urinary hydration biomarkers. We conclude that there may be some nutrients that are commonly consumed concomitantly (at the day level), across a variety of settings and populations, and that a limited subset of the clustering of these nutrients may associate with body water status.

Momentary Physical Activity Co-Occurs with Healthy and Unhealthy Dietary Intake in African American College Freshmen.

Background: Research investigating interrelations between physical activity and dietary intake has primarily used retrospective, summary-based measures of behavior subject to increased recall bias. This study used ecological momentary assessment (EMA) methods with accelerometry to determine within-day, momentary associations between physical activity and dietary intake behaviors in African American college freshmen. Methods: Participants (N = 50) completed a dietary EMA protocol that assessed food/fluids consumed over the past 2 h at five random times per day and wore an activPAL accelerometer for 7 days to measure physical activity. Physical activity was operationalized as step counts in the 2 h prior to the EMA prompt (matching the EMA recall window). Results: On occasions when participants took more steps than was typical for them in the 2 h prior to the EMA prompt, they were more likely to consume sugar-sweetened beverages (OR = 1.37, p < 0.001), water (OR = 1.28, p < 0.001), fruit (OR = 1.44, p < 0.001), vegetables (OR = 1.19, p = 0.02), and fried fast food (OR = 1.21, p = 0.04) over that same time. Conclusion: Momentary physical activity co-occurred with momentary consumption of both healthy and unhealthy dietary intake. These behavioral interrelations suggest potential implications for obesity risk and multiple health behavior change interventions in young adult African Americans.

Racial and Sex Differences in 24 Hour Urinary Hydration Markers among Male and Female Emerging Adults: A Pilot Study.

The purpose of this study was to examine 24 h urinary hydration markers in non-Hispanic White (WH) and non-Hispanic Black (BL) males and females. Thirteen males (BL, n = 6; WH, n = 7) and nineteen females (BL, n = 16, WH, n = 3) (mean ± SD; age, 20 ± 4 y; height, 169.2 ± 12.2 cm; body mass, 71.3 ± 12.2 kg; body fat, 20.8 ± 9.7%) provided a 24 h urine sample across 7 (n = 13) or 3 (n = 19) consecutive days (148 d total) for assessment of urine volume (UVOL), urine osmolality (UOSM), urine specific gravity (USG), and urine color (UCOL). UVOL was significantly lower in BL (0.85 ± 0.43 L) compared to WH college students (2.03 ± 0.70 L) (p < 0.001). Measures of UOSM, USG, and UCOL, were significantly greater in BL (716 ± 263 mOsm∙kg-1, 1.020 ± 0.007, and 4.2 ± 1.4, respectively) compared to WH college students (473 ± 194 mOsm∙kg-1, 1.013 ± 0.006, 3.0 ± 1.2, and respectively) (p < 0.05). Differences in 24 h urinary hydration measures were not significantly different between males and females (p > 0.05) or between the interaction of sex and race/ethnicity (p > 0.05). Non-Hispanic Black men and women were inadequately hydrated compared to their non-Hispanic White counterparts. Our findings suggest that development of targeted strategies to improve habitual fluid intake and potentially overall health are needed.