Racial Discrimination and Hypothalamic-Pituitary-Adrenal Axis Dysregulation in Adolescents With Overweight and Obesity: Does Context Matter?

OBJECTIVES: In adolescents at higher risk for chronic disease, the role that context of a discriminatory event may play on cortisol dysregulation is unclear. The purpose of this study was to perform a cross-sectional analysis examining the association between racial discrimination context (peer, educational, institutional, and cumulative) and diurnal cortisol patterning in adolescents with overweight and obesity. METHODS: One hundred adolescents (13-19 years; 49% non-Hispanic Black; 65% female; body mass index percentile = 93.9% [4.14%]) were included in this analysis. Racial discrimination context was measured using the self-reported Adolescent Discrimination Distress Index. Salivary cortisol, collected across 3 days at five time points during the day, was used to calculate Δ 0-30 minutes, diurnal slope, and average total diurnal cortisol area under the curve. Sixteen separate multivariable linear regression models were performed to analyze the relationship between racial discrimination and diurnal cortisol patterns. RESULTS: Primary findings show that cumulative racial discrimination and peer discrimination were associated with a greater diurnal slope (cumulative: ß = 0.010 ± 0.004, p = .03; peer: ß = 0.023 ± 0.010, p = .026). CONCLUSIONS: Findings from this study identified cross-sectional associations between racial discrimination experienced among peers and diurnal cortisol patterns in adolescents with overweight/obesity. If our findings were to be confirmed in longitudinal analyses, evidence-based programs should be considered to buffer the effects of discrimination on adolescent health, and more importantly, policy makers should work to eliminate discrimination exposure.

An exploratory analysis examining differences in physical activity and motor competence in children with and without asthma: brief report.

OBJECTIVE: The purpose of this pilot study was to examine potential differences in motor competence (MC) and physical activity (PA) between children with and without asthma. METHODS: Thirty-seven children and adolescents completed the Exercises for a Healthy Asthma Lifestyle and Enjoyment study (46% with asthma, 51% female, 11.1 ± 0.4 years, and 46% White). Motor competence was assessed using the Movement Assessment Battery for Children 2nd edition (MABC-2). PA was assessed using accelerometry. RESULTS: Children with asthma had significantly lower MC in the domain of aiming and catching (with asthma: 8.2 ± 0.4 vs. without asthma: 9.9 ± 0.5; p = 0.03) and fewer daily minutes spent in moderate-to-vigorous PA (MVPA) (with asthma: 18.0 ± 2.3 min vs. without asthma: 27.2 ± 3.6 min; p = 0.047). There were no significant group differences in manual dexterity, balance, total MABC-2 score, or total daily PA (all ps > 0.05). CONCLUSIONS: This study provides confirmatory evidence that children with asthma display lower MC and spend less time in MVPA compared to children without asthma. Because MC is a prerequisite for engaging in PA, future research should seek to determine if the differences observed in MC contribute to disparities in MVPA observed in this clinical population.

Classroom-Based Strategies to Reduce Disparities in Physical Activity Among Children with Asthma.

Children with asthma often experience physical activity (PA) induced symptoms 5-15 min following the start of exercise. Classroom PA breaks provide short intermittent bouts of PA and may represent a novel strategy to safely promote PA participation in this clinical population. The purpose of this study was to determine the feasibility of a classroom-based PA intervention, Interrupting Prolonged Sitting with Activity (InPACT), where teachers implement 5 × 4-min moderate-to-vigorous physical activity (MVPA) breaks throughout the school day. Nine classrooms at one elementary-middle school in Detroit, MI (student demographics: 79% Hispanic; 80% on free/reduced lunch; 31% prevalence of asthma and asthma-like symptoms) participated in this 20-week intervention. Asthma status was self-reported via the International Study of Asthma and Allergies in Childhood (ISAAC) Video Questionnaire in conjunction with nurse documentation. PA participation, exercise intensity, and asthmatic symptom occurrence were assessed via direct observation. Students accumulated approximately 17 min of activity per day during PA breaks. Compared to students without asthma, a higher percentage of students with asthma participated in MVPA (asthma: 52.9% ± 1.2%; non-asthma: 46.2% ± 0.8%; p = 0.01), a lower percentage participated in light PA (asthma: 25.9% ± 1.0%; non-asthma: 30.1% ± 0.7%; p = 0.01), and sedentary time during activity breaks (asthma: 21.2% ± 0.9%; non-asthma: 23.8% ± 0.7%; p = 0.02). Out of 294 observations, six instances of asthmatic symptoms (coughing) were observed in students with asthma 5-15 min following the PA break. Symptoms self-resolved within 15-min of the PA break and did not result in sustained exercise-induced bronchoconstriction. Classroom-based interventions that incorporate short intermittent bouts of PA represent safe exercises for children with asthma and may help to reduce PA disparities in this clinical population.

Psychological Responses to Intermittent Activities in Children With and Without Asthma.

PURPOSE: The purpose of this study was to examine the psychological responses to intermittent activities of varying intensities and types among children with and without asthma. METHODS: A total of 37 children and adolescents (51% male, aged 8-16 y, 54% nonwhite, and 54% without asthma) participated in this study. Participants completed 5 exercises in the same order: self-paced walking, resistance activities, dance video, gamified obstacle course, and step test. In-task mood was assessed using the Feeling Scale, in-task perceived exertion was assessed via the ratings of perceived exertion scale, and postactivity enjoyment was assessed using the Physical Activity Enjoyment Scale. RESULTS: There was a significant main effect of exercise type on mood (P < .001), ratings of perceived exertion (P < .001), and enjoyment (P < .002). There was not a significant main effect of asthma status on mood, ratings of perceived exertion, or enjoyment (Ps > .05). Children with asthma reported significantly lower in-task mood during the step exercise (P < .037) and reported significantly lower postactivity enjoyment after the walk and obstacle course exercises (Ps < .03). CONCLUSIONS: Regardless of differences by asthma status for in-task mood during the obstacle course and for postactivity enjoyment during the walk and step exercises, both children with and without asthma reported high in-task mood and postactivity enjoyment during all 5 exercises.

Adapting the InPACT Intervention to Enhance Implementation Fidelity and Flexibility.

Adapting classroom-based physical activity interventions are critical for program feasibility and fidelity in low-resource elementary schools. The purpose of this pilot study was to use Replicating Effective Programs (REP) framework to tailor the Interrupting Prolonged sitting with ACTivity (InPACT) intervention and evaluate its effectiveness on program fidelity in classrooms within a low-resource school. REP was applied to adapt program packaging, teacher training, and technical assistance to disseminate Tailored InPACT, a 20-week intervention where teachers implemented 5 × 4-min activity breaks per day. Tailored InPACT was implemented in nine, 3rd-6th grade classrooms in one low-resource school in Detroit Michigan (80% qualified for free/reduced lunch). Intervention fidelity was measured via daily, weekly, and end-of-study self-report questionnaires and direct observation. Throughout the 20-week intervention period, 3rd-5th grade teachers achieved intervention dose (5 activity breaks per day at an average duration of 4 min 8 s). Sixth grade teachers did not achieve intervention dose as they were only able to implement 2 activity breaks per day at an average duration of 4 min 12 s. These findings suggest 5 × 4-min classroom activity breaks per day is a feasible dose of classroom activity that 3rd-5th grade teachers can implement in low-resource classroom settings. Additional adaptations are needed to maximize fidelity in 6th grade classrooms.

Adolescent stress: A predictor of dieting behaviors in youth with overweight/obesity.

OBJECTIVE: To examine associations between psychological stress and dieting behavior along with the heterogeneity of this association by gender and race in a diverse sample of adolescents with overweight/obesity. METHODS: One hundred and sixty-one adolescents between the ages of 13-19 years of age with overweight/obesity (65% female; 53% non-Hispanic black/47% non-Hispanic white; age: 16.7 ± 1.7 years) were recruited from Southeast MI and included in this analysis. Psychological stress was measured using the Perceived Stress Scale, and dieting behavior was assessed using the dieting subscale from the Eating Attitudes Test (EAT-26) questionnaire. Multivariable linear regression models were conducted to examine the association between psychological stress and dieting behavior by gender and race. RESULTS: Psychological stress was significantly associated with dieting (ß = 0.18 ± 0.06; p < 0.01), with greater stress associated with greater frequency of dieting behavior. This relationship remained significant (ß = 0.15 ± 0.06; p = 0.016), even when controlling for covariates (age, body fat, gender, race, and pubertal development). There were no statistically significant differences in the association of psychological stress and disordered eating indices by gender or race/ethnicity (p's > 0.05). CONCLUSIONS: Increased psychological stress is associated with increased dieting behavior among adolescents with overweight/obesity. These findings suggest that psychological stress equally affects dieting behavior among adolescents with overweight/obesity, regardless of gender and race. Future studies should seek to identify the unique sources of psychological stress that contribute to increased dieting behavior among adolescents with overweight/obesity.

Acute Effects of Interrupting Prolonged Sitting With Intermittent Physical Activity on Blood Pressure in Preadolescent Children.

PURPOSE: To compare the acute effects of intermittent physical activity (PA) across 4 different intensities on blood pressure. METHODS: Thirty children (12 males and 18 females; aged 7-11 y; 33% overweight/obese; 53% nonwhite) completed 4 experimental conditions in random order: 8 hours sitting interrupted with 20, 2-minute low-, moderate-, high-intensity PA breaks, or sedentary screen-time breaks. PA intensity corresponded with 25%, 50%, and 75% of heart rate reserve. Blood pressure was measured during each condition in the morning (0800 h), noon (1200 h), and afternoon (1600 h). RESULTS: There were no significant differences across conditions for systolic blood pressure (SBP; all Ps > .05). There was a significant effect of time with SBP decreasing throughout the day for all conditions (average morning SBP: 106 [1] mm Hg, average noon SBP: 101 [2] mm Hg, average afternoon SBP: 103 [1] mm Hg; P = .01). There were no significant effects of condition or time on diastolic blood pressure (all Ps > .05). CONCLUSION: While sedentary behavior is known to be associated with hypertension in both adults and children, a single bout of prolonged sitting may be insufficient to produce hypertensive effects in otherwise healthy children. Future research should examine the appropriate dose of intermittent PA to accrue hypotensive responses in preadolescent children.

Chronic Stress and Cardiovascular Events: Findings From the CARDIA Study.

INTRODUCTION: Higher levels of perceived stress are associated with adverse cardiovascular health. It is plausible that these associations are attenuated among individuals with positive psychological factors such as social support and health-enhancing behaviors. Therefore, this study examined longitudinal associations of chronic stress with cardiovascular disease (CVD) events, and whether social support and physical activity (PA) modify these associations. METHODS: Data from 3,401 adults (mean age 40.2 years; 46.7% Black; 56.2% women) from the Coronary Artery Risk Development in Young Adults (CARDIA) study, with no prior CVD event in 2000-2001 were analyzed. Chronic stress lasting ≥6 months across 5 life domains (work, financial, relationships, health of self, and health of close other) was self-reported. Adjudicated CVD events (fatal/or nonfatal CVD event) were ascertained yearly through 2020. PA and social support were self-reported via questionnaires. Statistical analyses were conducted in 2023 using multivariable stepwise Accelerated Failure Time analysis to assess associations between key study variables. RESULTS: The mean chronic stress score was 1.30±1.33 stressors and, by 2020, 220 participants had experienced a CVD event. Chronic stress was associated with lowered survival (time ratio: 0.92; 95% CI: 0.854-0.989), when adjusted for sociodemographic and lifestyle variables but no longer significant when adjusting for clinical factors. Neither PA nor social support were significant modifiers (all ps>0.05). CONCLUSIONS: Chronic stress was associated with the risk of having a CVD event among middle-aged adults, due at least in part to clinical mediators. Studies should continue exploring positive psychosocial and behavioral factors that may modify this association.

A Novel Policy Alignment and Enhancement Process to Improve Sustainment of School-Based Physical Activity Programming.

The purpose of the current study was twofold: (1) to evaluate the strength and comprehensiveness of district wellness policies in one central Michigan intermediate school district (ISD; 16 districts), and (2) to pilot a novel policy alignment and enhancement process in one district within the ISD to improve sustainment of district-wide physical activity (PA) programming. Policy evaluation and alignment were determined using WellSAT 3.0. The Exploration, Preparation, Implementation, Sustainment (EPIS) framework was used to guide a seven-step policy alignment and enhancement process. Initial evaluation of the PA policy for the ISD revealed a strength score of 19/100 (i.e., included weak and non-specific language) and 31/100 for comprehensiveness (i.e., mentioned few components of the Comprehensive School Physical Activity Program). For the pilot school district, initial strength scores were 19/100 and 38/100 for comprehensiveness (exploration). An alignment of the tailored PA policy with current practices resulted in a 100% increase in strength (score of 38/100), and 132% increase in comprehensiveness (score of 88/100; preparation). However, district administrators encountered barriers to adopting the tailored policy and subsequently integrated the PA requirements into their curriculum guide and school improvement plan (implementation and sustainment). Future research should examine the effectiveness of our EPIS-informed policy evaluation, alignment, and enhancement process to promote widespread increases in student PA.

Racial differences in psychological stress and insulin sensitivity in non-Hispanic Black and White adolescents with overweight/obesity.

INTRODUCTION: Racial differences in type 2 diabetes risk persist among non-Hispanic Black and non-Hispanic White adolescents with overweight/obesity; however, the role of psychological stress in this disparity is less clear. PURPOSE: To examine racial differences in the association between psychological stress, insulin sensitivity (Si), acute insulin response to glucose (AIRg), and disposition index (DI) among non-Hispanic Black and non-Hispanic White adolescents with overweight/obesity. METHODS: Ninety-six adolescents (60% female; 51% non-Hispanic Black; 16.6 ± 1.8 years of age) with overweight/obesity (BMI percentile ≥ 85th percentile) were included in this analysis. Psychological stress was assessed using the 14-item Perceived Stress Scale. Glucose and insulin data from an intravenous glucose tolerance test was modeled to obtain Si, AIRg, and DI. Multivariable linear regression models were used to examine the association between race, psychological stress and metabolic outcomes (Si, AIRg, and DI). RESULTS: Race was a significant predictor of log-AIRg and log-DI (ps < 0.05) independent of all covariates in the main effect models. Lower Si (pinteraction = 0.014) and DI (pinteraction = 0.012) was also observed among Black adolescents who reported higher stress levels, whereas higher Si and DI was observed among non-Hispanic White adolescents reporting higher stress in the race interaction models. Race however, did not moderate the association between psychological stress and AIRg (p > 0.05), nor was stress associated with Si, AIRg, or DI ("p" "s" > 0.05) across all other models. CONCLUSIONS: Psychological stress may play an important and distinct role in shaping racial differences in type 2 diabetes risk among adolescents with overweight/obesity. Additional research is needed to understand the long-term effects of psychological stress on metabolic health among non-Hispanic Black and non-Hispanic White adolescents with overweight/obesity.

Weight stigma and physical activity avoidance among college-aged students.

This study explored cross-sectional associations between prior weight stigma experiences, physical activity (PA) intentions, behaviors, and the acute effects of a weight stigma exposure on PA intentions and behaviors among undergraduate students. Weight-stigma experiences and behavioral intentions were self-reported. Moderate-to-vigorous PA and total PA were assessed using accelerometry. Participants were randomized into two experimental conditions (a weight stigma or control condition) to assess the acute effects of a weight stigma exposure. Forty-nine students (81.6% female; 59.2% Non-Hispanic White; 19.6 ± 1.1 years of age; body mass index: 23.9 ± 4.0 kg/m2) completed the study. Prior weight stigma experiences were positively associated with PA avoidance (ß = 12.1 ± 2.7; p < .001) but were not associated with positive PA intentions or behaviors (ps > .05). There were no differences in positive PA intentions, PA avoidance, or PA behaviors across conditions (all ps > .05). Future studies should examine the long-term effects of weight stigma on PA avoidance and objectively measured PA in young college students.

Stress coping strategies and stress reactivity in adolescents with overweight/obesity.

This study explored the associations between the frequency and effectiveness of habitual stress coping strategies on physiological and psychological stress responses to an acute laboratory stressor in adolescents with overweight/obesity (51 adolescents; 47% female; ages 14-19 years). Coping strategies were assessed using the Schoolager's Coping Strategies Inventory. Acute physiological stress responses were measured as salivary cortisol and α-amylase output during the Trier Social Stress Test and during a control condition. Acute psychological stress was measured using a Likert-type scale, and systolic blood pressure (SBP) and heart rate were measured at baseline. Results revealed that higher coping effectiveness was associated with lower log-based α-amylase during the stress (ß = -0.025, p = 0.018) and control (ß = -0.030, p = 0.005) conditions, but not with cortisol across either condition (all ps > 0.05). SBP moderated the association between coping effectiveness and α-amylase during the stress condition, with higher coping effectiveness associated with lower α-amylase only among individuals with lower SBP (ß = 0.002, p = 0.027). Coping frequency was not associated with cortisol responses, neither was habitual stress coping strategies associated with psychological stress (all ps > 0.05). These findings provide preliminary evidence that effective use of stress coping strategies may provide a dampening effect on sympathetic activity in an at-risk adolescent population.

Acute Daily Stress, Daily Food Consumption, and the Moderating Effect of Disordered Eating among Adolescents with Overweight/Obesity.

Objective: The purpose of this study was to examine the associations between acute daily stress dimensions (frequency, sum) and food intake in adolescents with overweight/obesity, and to explore the potential moderating effect of disordered eating behaviors on these associations. Methods: One hundred eighty-two adolescents with overweight/obesity (65% females; 68.7% non-white; 16.2 ± 1.8 years of age) were included in this analysis. Acute daily stress was measured using the Daily Stress Inventory, and daily caloric intake was measured using a food frequency questionnaire. Disordered eating behavior was assessed using the Eating Attitudes Test (EAT-26). Results: Acute daily stress frequency (B = 0.013 ± 0.003; p < 0.001) and acute daily stress sum (B = 0.003 ± 0.001; p < 0.001) were associated with greater daily caloric intake. Disordered eating behavior moderated the association between acute daily stress frequency and caloric intake (pinteraction = 0.039), with greater daily caloric intake among those with higher levels of disordered eating. Disordered eating behavior did not significantly moderate the association between acute daily stress sum and daily caloric intake (pinteraction = 0.053). Conclusions: These findings suggest that greater exposure to acute daily stressors may increase daily food intake in adolescents with overweight/obesity, with greater susceptibility among those engaging in high levels of disordered eating. Longitudinal research is warranted to elucidate the long-term effect of acute daily stressors and disordered eating on food intake among adolescents with overweight/obesity. The Health and Culture Project is registered at www.clinicaltrials.gov (No. NCT02938663).

Psychological Stress and Lowered Physical Activity Enjoyment in Adolescents With Overweight/Obesity.

PURPOSE: The purpose of this study was 2-fold: 1) to determine the cross-sectional associations between psychological stress, physical activity enjoyment, and physical activity participation [moderate-to-vigorous physical activity (MVPA), total physical activity (TPA)]; and 2) to determine the moderating effect of physical activity enjoyment on the associations between stress, MVPA, and TPA in adolescents with overweight/obesity. DESIGN: Cross-sectional, secondary data analysis of the Health and Culture Project and the Stress, Obesity, and Diabetes in Adolescents study. SAMPLE: One hundred and ten adolescents (73% female; 65.4% non-white; age 15.8 ± 1.9 years) with overweight/obesity (BMI percentile ≥ 85th percentile) were included in this analysis. MEASURES: Psychological stress was assessed using the Perceived Stress Scale (PSS-14); enjoyment was measured via the Physical Activity Enjoyment Scale; and MVPA and TPA were objectively measured using accelerometry over a minimum of 4 days. RESULTS: Higher perceived stress was associated with lower physical activity enjoyment (ß = -0.41 ± 0.15; p = 0.008). Stress was not associated with MVPA or TPA (ps > 0.05), nor was enjoyment a significant moderator in the associations between stress and MVPA or stress and TPA (pinteraction > 0.05). CONCLUSIONS: These findings suggest that psychological stress is associated with lower physical activity enjoyment among adolescents with overweight/obesity. Longitudinal studies are needed to understand the long-term effects of stress on psychological factors that may serve as antecedents to physical activity participation among adolescents with overweight/obesity.

Community violence exposure and cortisol awakening responses in adolescents who are overweight/obese.

BACKGROUND: Community violence exposure has been identified as a salient environmental stressor associated with dysregulated cortisol awakening response (CAR), which may act to exacerbate hypothalamic-pituitary-adrenal (HPA) axis dysregulation observed in adolescents who are overweight/obese. PURPOSE: To perform an exploratory cross-sectional analysis examining the association between community violence exposure and CAR in adolescents who are overweight/obese. METHODS: One-hundred adolescents (ages: 13-19 years; 65% female; average BMI percentile: 93.80 ± 4.13) were included in this analysis. Community violence exposure was measured using the Survey of Children's Exposure to Community Violence. Salivary cortisol collected across three days at awakening and 30 min post-awakening was used to calculate CAR area under the curve (AUC). RESULTS: Community violence exposure was associated with a lower CAR AUC when controlling for baseline cortisol, sex, BMI, pubertal development, race and perceived stress (ß = -0.04 ± 0.02; p = 0.04). CONCLUSION: Findings from this study identified cross-sectional association between community violence and HPA dysregulation in adolescents who were overweight/obese. If long-term exposure to community violence does indeed accelerate HPA dysregulation in adolescents at increased weight status, policymakers and interventionists should consider implementing programs that limit adolescent violence exposure.

A Pilot Intervention Using Gamification to Enhance Student Participation in Classroom Activity Breaks.

The purpose of this study was to determine the effect of adding game design elements (goal setting, feedback, and external rewards) to an evidence-based physical activity intervention to increase in-class physical activity participation (intensity of activity breaks performed). Nine third- through sixth-grade classrooms (n = 292 students) in one elementary-middle school in Detroit, Michigan (49% female, 95% nonwhite; 80% qualified for free/reduced lunch) participated in this 20-week intervention where teachers implemented 5 × 4 min moderate-to-vigorous activity breaks per day. Gamification of activity breaks occurred during weeks 13-20 of the intervention and included the use of game design elements and classroom goals for activity break intensity. Moderate-to-vigorous physical activity (MVPA) during activity breaks was measured via direct observation. There was a significant effect of intervention with a 27% increase in student MVPA participation during the gamified intervention weeks compared with the standard intervention weeks (p = 0.03). Gamification of activity breaks resulted in 55% (compared with 25% during the standard intervention) of students accumulating approximately 20 min of health-enhancing physical activity per day in their classroom. These findings provide preliminary evidence that gamifying activity breaks may be an important strategy for increasing student participation in classroom activity breaks.

Perceived Stress Predicts Lower Physical Activity in African-American Boys, but not Girls.

OBJECTIVES: The purpose of this study was to examine cross-sectional relationships of psychological stress, stress coping, and minutes of moderate-to-vigorous physical activity (MVPA) in Amer- ican-American (AA) boys and girls. METHODS: A community-based sample of 139 AA adolescents (mean age 14.7 years; SD = 1.8 years; 64.7% girls; 30% obese) from Washtenaw County, Michigan was included in this analysis. Psychological stress was assessed using the Daily Stress Inventory and the Perceived Stress Scale. Coping strategies were evaluated using the Schoolager's Coping Strategies questionnaire. Physical activity was measured objectively via accelerometry. RESULTS: Compared to boys, girls participated in approximately 13 fewer minutes of MVPA (p < .001) per day and reported significantly higher levels of daily stress (p = .03) and perceived stress (p < .001). In addition, girls reported using a greater number of coping strategies (p = .01) at a greater frequency (p = .04) compared to boys. However, perceived stress significantly predicted lower levels of MVPA (p = .03) in boys only. CONCLUSIONS: There are important gender differences in how AA girls perceive, experience, and cope with stress compared to AA boys. Although AA girls reported higher levels of stress and employed more coping strategies, perceived stress was associated with physical inactivity in AA boys, but not girls. Additional research is warranted to better understand the influence of stress on the choice to be physically active in AA youth.

Racial Discrimination and Low Household Education Predict Higher Body Mass Index in African American Youth.

OBJECTIVE: The purpose of this study was to examine the relationships between environmental factors, including household education, community violence exposure, racial discrimination, and cultural identity, and BMI in African American adolescents. METHODS: A community-based sample of 198 African American youth (120 girls, 78 boys; ages 11-19 years) from Washtenaw County, Michigan, were included in this analysis. Violence exposure was assessed by using the Survey of Children's Exposure to Community Violence; racial discrimination by using the Adolescent Discrimination Distress Index; cultural identity by using the Acculturation, Habits, and Interests Multicultural Scale for Adolescents; and household education by using a seven-category variable. Measured height and body weight were used to calculate BMI. RESULTS: Racial discrimination was positively associated with BMI, whereas household education was inversely associated with BMI in African American adolescents (discrimination: ß = 0.11 ± 0.04, p = 0.01; education: ß = -1.13 ± 0.47, p = 0.02). These relationships were significant when accounting for the confounding effects of stress, activity, diet, and pubertal development. Significant gender interactions were observed with racial discrimination and low household education associated with BMI in girls only (discrimination: ß = 0.16 ± 0.05, p = 0.003; education: ß = -1.12 ± 0.55, p = 0.045). There were no significant relationships between culture, community violence exposure, and BMI (all p's > 0.05). CONCLUSION: Environmental factors, including racial discrimination and low household education, predicted higher BMI in African American adolescents, particularly among girls. Longitudinal studies are needed to better understand the mechanisms by which these environmental factors increase obesity risk in African American youth.

The effects of interrupting prolonged sitting with intermittent activity on appetite sensations and subsequent food intake in preadolescent children.

BACKGROUND: Short-term and long-term exposure to prolonged sitting is associated with excess food intake and weight gain in children. Interrupting prolonged sitting with low-intensity activity has been shown to not alter hunger, satiety, or food consumption in children, however it is unclear whether interrupting sitting with high-intensity activity will alter appetite regulation in children. PURPOSE: The purpose of this study was to examine the acute effects of interrupting prolonged sitting with intermittent activity performed at varying intensities on hunger, satiety, prospective food consumption (PFC), and food intake in preadolescent children. METHODS: Thirty-nine children (ages 7-11 years, 54% female, 33% overweight/obese) completed four experimental conditions in random order: 8 hours of sitting interrupted with 20, 2-minute low-, moderate-, or high-intensity activity breaks or 20, 2-minute sedentary screen time breaks. Exercise intensity corresponded with 25%, 50% and 75% of heart rate reserve, respectively. Hunger, satiety, and PFC were assessed using the Visual Analog Scale, at five time points (pre- and post-breakfast, pre- and post-lunch, and pre-dinner) during each experimental condition. Dietary compensation was assessed as total caloric intake during a post-condition dinner standardized to provide 70% of estimated daily energy requirements. RESULTS: There was a significant effect of time on hunger, satiety, and PFC throughout each condition day (p< 0.001). There were no differences across conditions for hunger (sedentary: 4.9±0.3 cm, low: 5.0±0.3 cm, moderate: 5.1±0.3 cm, high: 5.1±0.3 cm, p>0.05), satiety (sedentary: 4.7±0.3 cm, low: 4.4±0.3 cm, moderate: 4.6±0.3 cm, high: 4.2±0.3 cm, p>0.05), and PFC (sedentary: 4.9±0.3 cm, low: 4.7±0.3 cm, moderate: 4.9±0.3 cm, high: 5.0±0.3 cm, p>0.05). There were no significant differences in post-activity food intake across conditions (sedentary: 1071.9±53.6 kcals; low: 1092.6±43.4kcals; moderate: 996.2±54.6kcals; high: 1138.7±62.8kcals, p>0.05). However, there was a significant effect of condition on energy balance (sedentary: +61.4±65.9 kcals, low: +74.9±57.6 kcals, moderate: -58.3±62.8 kcals, high: -391.2±77.9 kcals; p<0.001). There were no significant effects of weight status on hunger, satiety, PFC, post-activity food intake, and mean energy balance across conditions (all p's>0.05). CONCLUSIONS: Interrupting prolonged sitting with physical activity of any intensity does not alter appetite sensations and subsequent food consumption in children. These data suggest that interventions targeting prolonged sitting with high-intensity intermittent activity may be an effective strategy to increase physical activity energy expenditure without increasing food intake, allowing for a short-term energy deficit in both healthy weight and overweight/obese children. Future studies should examine the long-term effects of interrupting prolonged sitting with activity on food consumption and weight status in preadolescent children.