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Neurodegenerative diseases such as Alzheimer’s have recently been linked to hypertension (HTN). S100B is a marker of cerebral injury and the progression of neuro-degeneration. Serum levels of S100B are known to be increased after acute brain trauma, with the progression of chronic neuro-degenerative diseases, and even in the presence of HTN. Optimization of aerobic fitness has long been implicated in the treatment and prevention of HTN. However, no study has investigated whether aerobic exercise training (AEXT) has an effect on the prevention of hypertension associated neurodegenerative disease markers such as S100B.METHODS: 18 participants ages 40-62 were assessed. To be considered for inclusion participants had to be free of any cardiovascular disease, non-smoking and sedentary. After inclusion participants underwent blood draws, blood pressure (BP) measurements, flow mediated dilation (FMD) analysis using Doppler ultrasound and aerobic exercise testing by measuring VO2max. Participants then followed AEXT (3days/week, 65% of VO2max, 40 minutes/day) for 6 months. S100B serum levels were assessed using an ELISA Assay (Milipore, USA).Results: AEXT did not significantly change serum S100B levels or BP. However, VO2max fitness levels (24.55 ± 1.01 vs. 27.52 ± 1.59 mL/kg/min) and FMD percentage (6.47 ± 0.9 vs. 9.75 ± 1.09 %) increased significantly (p0.008 and p0.048 respectively). Although there were no significant correlations between S100B and the above variables before and after AEXT, S100B levels were inversely correlated with VO2max after the six months of AEXT (r = -.594, p0.009). Also, participants who improved their VO2max level by at least 3ml/kg/min (N=10) had significantly (p0.008) lower S100B levels (45.43 ± 11.9 vs. 64.19 ± 14.16 pg/mL) after the completion of AEXT than participants who did not (N=8).Conclusion: Although AEXT did not lower BP, it did improve endothelial function. Also, people who responded to AEXT, had significantly better S100B levels. Additionally, the fact that S100B was inversely correlated to VO2max, as was the case after AEXT, implicates a potential role for the improvement of aerobic fitness in the prevention of HTN-associated neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Background: High dietary sodium (Na) intake has been shown to be related to the development of endothelial dysfunction and hypertension. Urinary sodium excretion in people with normal renal function can indirectly reflect the level of dietary sodium intake. The purpose of the study was to test whether high urine Na excretion was independent from other risk factors and related to the compromised endothelial-dependent (fiow-mediated dilation [FMD]) and/or endothelium-independent (nitroglycerin-induced dilation [NMD]) in normotensive African Americans. Normotensives were studied in order to eliminate the influence of hypertension.METHODS: Urine was collected for 24 hr in 30 subjects aged 41-63 yrs with normal blood pressure (125.7 ± 9.7/81 ± 7.1 mmHg). 16 subjects had Na excretion <150 mmol (99.6 ± 24.8 mmol) and were classified as the Normal Na excretion group and 14 subjects had Na excretion ≥150 mmol/g (186.5 ± 27.1 mmol) and were classified as the High Na excretion group. FMD was measured after 5-min cuff occlusion and NMD was measured after application of 0.8 mg nitroglycerin using Doppler ultrasound. The maximum FMD- and NMD-diameters and FMD/NMD ratio were calculated.Results: There were no differences in other dietary factors, age, body mass index, blood pressure, or physical activity levels between the groups. Plasma concentrations of cholesterol, glucose, antioxidant status and inflammatory markers did not differ between groups. FMD (Normal: 7.4 ± 2.9% vs. High: 9.5 ± 3.6%; p=0.09) and NMD (Normal: 17.9 ± 6.3% vs. High: 27.8 ± 18.1%; p=0.07) and true peak FMD/NMD ratio (Normal: 0.45 ± 0.22 vs. High: 0.38 ± 0.11; p=0.26) were not different between groups. No significant correlations were found between 24hr Na excretion and FMD (r=0.332; p=0.073), NMD (r=0.356; p=0.053) or FMD/NMD ratio(r=0.112; p=0.554) in the entire study group.Conclusion: High Na excretion was not associated with reduced endothelial responsiveness in healthy African Americans with normal blood pressure. These results suggest that high Na intake may not be predictive of endothelial dysfunction in putatively healthy populations. [ABSTRACT FROM AUTHOR]

Purpose: Sedentary time is ubiquitous in developed nations and is associated with deleterious health outcomes. Physical activity guidelines recommend reductions in sedentary time; however, quantitative guidelines that inform how often and how long sedentary time should be interrupted have not been provided. The purpose of this study was to examine the acute effects of multiple doses of a sedentary break intervention on cardiometabolic risk factors, concurrently evaluating efficacy of varying frequencies and durations of sedentary breaks. Methods: In a randomized crossover study, middle- and older-age adults (n = 11) completed the following 8-h conditions on five separate days: 1 uninterrupted sedentary (control) condition and four acute (experimental) trials that entailed different sedentary break frequency/duration combinations: every 30 min for 1 min, every 30 min for 5 min, every 60 min for 1 min, and every 60 min for 5 min. Sedentary breaks entailed light-intensity walking. Glucose and blood pressure (BP) were measured every 15 and 60 min, respectively. Results: Compared with control, glucose incremental area under the curve was significantly attenuated only for the every 30 min for 5-min dose (−11.8[4.7]; P = 0.017). All sedentary break doses yielded significant net decreases in systolic BP from baseline compared with control (P < 0.05). The largest reductions in systolic BP were observed for the every 60 min for 1 min (−5.2 [1.4] mm Hg) and every 30 min for 5 min (−4.3[1.4] mm Hg) doses. Conclusions: The present study provides important information concerning efficacious sedentary break doses. Higher-frequency and longer-duration breaks (every 30 min for 5 min) should be considered when targeting glycemic responses, whereas lower doses may be sufficient for BP lowering. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Physical activity studies often utilize wearable devices to measure participants' habitual activity levels by averaging values across several valid observation days. These studies face competing demands–available resources and the burden to study participants must be balanced with the goal to obtain reliable measurements of a person's longer-term average. Information about the number of valid observation days required to reliably measure targeted metrics of habitual activity is required to inform study design. Methods: To date, the number of days required to achieve a desired level of aggregate long-term reliability (typically 0.80) has often been estimated by applying the Spearman-Brown Prophecy formula to short-term test-retest reliability data from studies with single, relatively brief observation windows. Our work, in contrast, utilizes a resampling-based approach to quantify the long-term test-retest reliability of aggregate measures of activity in a cohort of 79 participants who were asked to wear a FitBit Flex every day for approximately one year. Results: The conventional approach can produce reliability estimates that substantially overestimate the actual test-retest reliability. Six or more valid days of observation for each participant appear necessary to obtain 0.80 reliability for the average amount of time spent in light physical activity; 8 and 10 valid days are needed for sedentary time and moderate/vigorous activity respectively. Conclusion: Protocols that result in 7–10 valid observation days for each participant may be needed to obtain reliable measurements of key physical activity metrics. [ABSTRACT FROM AUTHOR]

Objectives Derive latent profiles of accelerometry-measured moderate–vigorous physical activity (MVPA) for Hispanic/Latino adults, examine associations between latent MVPA profiles and neurocognition, and describe profiles via self-reported MVPA. Methods Complex survey design methods were applied to cross-sectional data from 7,672 adults ages 45–74 years in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL; 2008–2011). MVPA was measured via hip-worn accelerometers. Latent profile analysis was applied to derive latent MVPA profiles (minutes/day of week). Neurocognition was assessed with the Brief-Spanish English Verbal Learning Test (B-SEVLT) Sum, B-SEVLT Recall, Controlled Oral Word Association Test (word fluency), and Digit Symbol Substitution (DSS) test. All tests were z -scored, and a global neurocognition score was generated by averaging across scores. Survey linear regression models were used to examine associations between latent MVPA profiles and neurocognitive measures. Self-reported MVPA domains were estimated (occupational, transportation, and recreational) for each latent profile. Results Four latent MVPA profiles from the overall adult target population (18–74 years) were derived and putatively labeled: No MVPA, low, moderate, and high. Only the high MVPA profile (compared to moderate) was associated with lower global neurocognition. Sensitivity analyses using latent MVPA profiles with only participants aged 45–74 years showed similar profiles, but no associations between latent MVPA profiles and neurocognition. The occupational MVPA domain led in all latent MVPA profiles. Discussion We found no consistent evidence to link accelerometry-measured MVPA profiles to neurocognitive function. Research to better characterize the role of high occupational MVPA in relation to neurocognition among Hispanic/Latino adults are needed. [ABSTRACT FROM AUTHOR]

Purpose: Sedentary behavior is associated with poor physical function in older adults, which can lead to accelerated skeletal muscle aging (sarcopenia) and premature mortality. We examined the independent and joint effects of sedentary behavior and moderate to vigorous intensity physical activity (MVPA) with measures of physical functioning. Methods: We studied 5408 participants in the REasons for Geographic and Racial Differences in Stroke study who wore a hip-mounted accelerometer over seven consecutive days (2009–2013) and had self-reported and directly observed physical function (time walk, chair stand test) measured during an in-home visit conducted from 2013 to 2016. Results: Greater sedentary time was significantly associated with poorer chair stand and timed walk scores. Substituting 30 min of sedentary time with 30 min of MVPA was associated with significant improvements in chair stands (β −0.57; P = 0.007) and timed walk (β −0.36; P = 0.01). Similar, but less robust, findings were observed for reallocations of sedentary time to light-intensity physical activity. In joint association analyses, high sedentary time in combination with low MVPA (but not in combination with high MVPA) was associated with poorer physical function compared with the referent group (low sedentary time/high MVPA; P < 0.001 for all). Conclusions: Greater time spent being sedentary was associated with worse physical functioning outcomes. However, reallocations of sedentary time to light-intensity physical activity, and especially MVPA, were associated with more favorable physical functioning. Interventions aimed to increase MVPA and reduce sedentary behavior should be a priority, especially among populations at greatest risk for sarcopenia and physical function decline. [ABSTRACT FROM AUTHOR]

Introduction: African Americans are disproportionately affected by high blood pressure, which may be associated with exposure to air pollutants, such as fine particulate matter and ozone.Methods: Among African American Jackson Heart Study participants, this study examined associations between 1-year and 3-year mean fine particulate matter and ozone concentrations with prevalent and incident hypertension at Visits 1 (2000-2004, n=5,191) and 2 (2005-2008, n=4,105) using log binomial regression. Investigators examined associations with systolic blood pressure, diastolic blood pressure, pulse pressure, and mean arterial pressure using linear regression and hierarchical linear models, adjusting for sociodemographic, behavioral, and clinical characteristics. Analyses were conducted in 2017-2019.Results: No associations were observed between fine particulate matter or ozone concentration and prevalent or incident hypertension. In linear models, an IQR increase in 1-year ozone concentration was associated with 0.67 mmHg higher systolic blood pressure (95% CI=0.27, 1.06), 0.42 mmHg higher diastolic blood pressure (95% CI=0.20, 0.63), and 0.50 mmHg higher mean arterial pressure (95% CI=0.26, 0.74). In hierarchical models, fine particulate matter was inversely associated with systolic blood pressure (-0.72, 95% CI= -1.31, -0.13), diastolic blood pressure (-0.69, 95% CI= -1.02, -0.36), and mean arterial pressure (-0.71, 95% CI= -1.08, -0.33). Attenuated associations were observed with 1-year concentrations and at Visit 1.Conclusions: Positive associations were observed between ozone and systolic blood pressure, diastolic blood pressure, and mean arterial pressure, and inverse associations between fine particulate matter and systolic blood pressure, diastolic blood pressure, and mean arterial pressure in an African American population with high (56%) prevalence of hypertension. Effect sizes were small and may not be clinically relevant. [ABSTRACT FROM AUTHOR]

The cross-stressor adaptation hypothesis of exercise training has not been investigated under real-life conditions. Using ecological momentary assessment, we tested whether usual exercise level moderates the relationship of self-reported anxiety to concurrent ambulatory heart rate (HR) and systolic/diastolic blood pressure (SBP/DBP). Participants (N = 832) completed 24-h ambulatory monitoring of HR/BP, using a brachial BP cuff that took readings at 28-min intervals. Anxiety levels were concurrently reported on a visual analog scale (VAS) using a Palm Pilot. Usual exercise behavior was assessed by a self-report questionnaire. Random coefficients linear regression models predicting momentary HR/BP readings from time-matched anxiety scores were estimated, yielding the average within-person effect (slope) of anxiety. The interaction of exercise level (i.e., no weekly exercise, 1–149, and ≥ 150 min/week; a between-person factor) with anxiety was added to the model in order to estimate the average anxiety slope for participants in each exercise category. The relationship of HR/BP to anxiety did not differ significantly among exercise categories, hence not providing evidence for the cross-stressor hypothesis. In an exploratory analysis of the difference in HR/BP between occasions when anxiety was in the top versus bottom person-specific quintiles of responses, the difference in HR (but not SBP or DBP) varied significantly by exercise level (F(2,625) = 4.92, p = 0.008). Though our pre-specified analysis did not support the hypothesis, we provide some post hoc evidence supporting the cross-stressor hypothesis of exercise training for the HR response to anxiety. [ABSTRACT FROM AUTHOR]

Background: The psychological factors underlying physical inactivity in vulnerable cardiac adult populations remain understudied. Anxiety sensitivity, a cognitive vulnerability defined as fear of the physical, cognitive, and social consequences of anxiety, may be an important modifiable determinant of physical inactivity. We examined the association of anxiety sensitivity, and each anxiety sensitivity subscale (physical, cognitive, and social concerns), with physical inactivity in adults with a history of myocardial infarction (MI). Methods: Using cross-sectional data from a nationally representative survey of adults (N = 1417) in the USA who reported a health professional diagnosis of MI, we used weighted logistic regression models to evaluate the association between anxiety sensitivity (overall, and each subscale) and physical inactivity (self-reported exercise 0–1 day/week), with adjustment for age, gender, race, education, number of MIs, and depression. Results: Overall, 34.3% reported physical inactivity. Anxiety sensitivity was associated with greater odds of physical inactivity (OR = 1.01; 95% CI = 1.00, 1.02; p =.026). Of the subscales, only physical concerns were associated with physical inactivity (OR = 1.02; 95% CI = 1.01, 1.04; p =.008) in the final model. High vs. low fear of shortness of breath was most consistently associated with physical inactivity (OR = 1.49; 95% CI = 1.08, 2.06; p <.021). Conclusion: Anxiety sensitivity, generally, and fear of the physical sensations of anxiety (i.e., "fear of shortness of breath"), specifically, are important correlates of physical inactivity in adults with a history of MI. Future research should replicate these findings and experimentally test whether cardiac rehabilitation interventions that include an adjunctive component targeting reduction of anxiety sensitivity overall, or specific somatic symptoms, improve physical activity in this population. [ABSTRACT FROM AUTHOR]

Introduction: Physical inactivity, high screen time, and short sleep are targets of public health initiatives for children. However, few data exist on how many U.S. children meet guidelines for these behaviors-data vital to inform which needs greater targeting. This study describes national prevalence estimates of U.S. children who meet physical activity, screen time, and sleep guidelines alone or in combination across each childhood year.Methods: This analysis (completed in 2019) used cross-sectional data from the 2016-2017 National Survey of Children's Health, a nationally representative sample of U.S. children. Child physical activity (days per week with ≥60 minutes), recreational screen time (hours per day of TV viewing and electronic device use), and sleep duration (hours per day) were assessed through parental report. Guidelines recommend ≥60 minutes per day of physical activity, ≤2 hours per day of screen time, and 9-12 hours per day of sleep for individuals aged 6-12 years (8-10 hours for those aged 13-17 years).Results: Only 8.8% (95% CI=8.2%, 9.5%) of U.S. children meet all the 3 guidelines combined. Majority of children/adolescents attain the sleep guideline (86.0%, 95% CI=85.2%, 86.7%), but a lower proportion meet physical activity (23.0%, 95% CI=22.1%, 23.9%) or screen time (32.9%, 95% CI=31.9%, 33.8%) guidelines. A substantial age effect was identified, with prevalence of meeting each distinct guideline and all the 3 declining with age (p<0.001).Conclusions: Few U.S. children meet all the 3 movement guidelines, with prevalence rates of children meeting guidelines declining with age. Although many meet sleep guidelines, few meet physical activity or screen time guidelines. Initiatives targeting physical activity and screen time, especially for adolescents, should be pursued. [ABSTRACT FROM AUTHOR]

Abstract Background Guidelines recommend exercise for secondary prevention of acute coronary syndrome (ACS), however adherence to guidelines is low. A paucity of data examining factors associated with objectively-measured exercise post-discharge in ACS survivors exists. The purpose of this study was to identify factors associated with exercise during the 5 weeks after ACS discharge. Methods A sample of 151 ACS patients treated at a university hospital were enrolled into an observational cohort study and wore an accelerometer for 35 days post-discharge. Days on which participants accumulated ≥30 min of moderate-to-vigorous physical activity in bouts ≥10 min were considered exercise days. Participants were categorized as non-exercisers (0 exercise days) or exercisers (≥1 exercise day). A multi-variable logistic regression model was used to examine the association between exercise and socio-demographics, depression, SF-12 physical and mental health scores, disease severity, length of hospitalization, and percutaneous coronary intervention. Results 39.7% of participants were non-exercisers. Factors associated with non-exercise were age (OR: 1.11; 95% CI: 1.06–1.17, p < 0.001), female sex (OR: 2.76; 95% CI: 1.10–6.95, p = 0.031), and lower SF-12 physical health score (OR: 0.94; 95% CI: 0.90–0.98, p = 0.005). Conclusion In ACS patients in whom exercise participation was objectively measured for 5 weeks post-discharge, demographic and poor physical health factors were associated with non-exercise. These findings identify populations (e.g. older adults, women) at especially high risk for being physically inactive in whom more intense intervention may be warranted. Highlights • A striking 40% of patients did not exercise a single day over 5 weeks post-ACS. • Older age, female sex, and poor physical health were associated with non-exercise. • Older adults and women may need robust intervention to promote exercise post-ACS. [ABSTRACT FROM AUTHOR]

Introduction: This intervention study used mobile technologies to investigate whether those randomized to receive a personalized "activity fingerprint" (i.e., a one-time tailored message about personal predictors of exercise developed from 6 months of observational data) increased their physical activity levels relative to those not receiving the fingerprint.Study Design: A 12-month randomized intervention study.Setting/participants: From 2014 to 2015, 79 intermittent exercisers had their daily physical activity assessed by accelerometry (Fitbit Flex) and daily stress experience, a potential predictor of exercise behavior, was assessed by smartphone.Intervention: Data collected during the first 6 months of observation were used to develop a person-specific "activity fingerprint" (i.e., N-of-1) that was subsequently sent via email on a single occasion to randomized participants.Main Outcome Measures: Pre-post changes in the percentage of days exercised were analyzed within and between control and intervention groups.Results: The control group significantly decreased their proportion of days exercised (10.5% decrease, p<0.0001) following randomization. By contrast, the intervention group showed a nonsignificant decrease in the proportion of days exercised (4.0% decrease, p=0.14). Relative to the decrease observed in the control group, receipt of the activity fingerprint significantly increased the likelihood of exercising in the intervention group (6.5%, p=0.04).Conclusions: This N-of-1 intervention study demonstrates that a one-time brief message conveying personalized exercise predictors had a beneficial effect on exercise behavior among urban adults. [ABSTRACT FROM AUTHOR]

Background: Psychosocial stress contributes to heart disease in part by adversely affecting maintenance of health behaviors, while exercise can reduce stress. Assessing the bi-directional relationship between stress and exercise has been limited by lack of real-time data and theoretical and statistical models. This lack may hinder efforts to promote exercise maintenance.Purpose: We test the bi-directional relationship between stress and exercise using real-time data for the average person and the variability-individual differences-in this relationship.Methods: An observational study was conducted within a single cohort randomized controlled experiment. Healthy young adults, (n = 79) who reported only intermittent exercise, completed 12 months of stress monitoring by ecological momentary assessment (at the beginning of, end of, and during the day) and continuous activity monitoring by Fitbit. A random coefficients linear mixed model was used to predict end-of-day stress from the occurrence/non-occurrence of exercise that day; a logistic mixed model was used to predict the occurrence/non-occurrence of exercise from ratings of anticipated stress. Separate regression analyses were also performed for each participant. Sensitivity analysis tested all models, restricted to the first 180 days of observation (prior to randomization).Results: We found a significant average inverse (i.e., negative) effect of exercise on stress and of stress on exercise. There was significant between-person variability. Of N = 69, exercise was associated with a stress reduction for 15, a stress increase for 2, and no change for the remainder. We also found that an increase in anticipated stress reported the previous night or that morning was associated with a significant 20-22% decrease (OR = 0.78-0.80) in the odds of exercising that day. Of N = 69, this increase in stress reduced the likelihood of exercise for 17, increased the odds for 1, and had no effect for the remainder. We were unable to identify psychosocial factors that moderate the individual differences in these effects.Conclusions: The relationship of stress to exercise can be uni- or bi-directional and varies from person to person. A precision medicine approach may improve exercise uptake. [ABSTRACT FROM AUTHOR]

Background: The 24-h activity cycle (24H-ACT) (sleep, sedentary behavior, light physical activity, and moderate to vigorous physical activity) may have deleterious or beneficial associations with 24-h blood pressure (24H-BP)., Purpose: Estimate the short-term associated changes in 24H-BP with acutely replacing 30 min/d from one behavior of the 24H-ACT to other behaviors in employed adults., Methods: Participants (N = 659) wore an ambulatory blood pressure monitor and two accelerometers (waist and wrist) to measure 24H-BP and the 24H-ACT., Results: Replacing 30 min of sedentary behavior with 30 min of sleep was associated with lower 24-h mean systolic [ß = -0.32 mm Hg per 0.5 h (95% CI: -0.58, 0.06)] and diastolic [ß = -0.31 mm Hg per 0.5 h (95% CI: -0.50, -0.12)] blood pressure. Replacing 30 min of light physical activity with 30 min of sleep was associated with lower 24-h mean systolic [ß = -0.30 mm Hg per 0.5 h (95% CI: -0.62, 0.03,)] and diastolic blood pressure [ß = -0.34 mm Hg per 0.5 h (95% CI: -0.58, -0.11)]. No other time reallocations between 24H-ACT behaviors were associated with changes in 24H-BP., Conclusion: Replacing time in sedentary behavior or light physical activity with sleep may provide small short-term reductions in that day's 24H-BP., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Journal of Hypertension, Ltd. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

This paper introduces functional quantile principal component analysis (FQPCA), a dimensionality reduction technique that extends the concept of functional principal components analysis (FPCA) to the examination of participant-specific quantiles curves. Our approach borrows strength across participants to estimate patterns in quantiles, and uses participant-level data to estimate loadings on those patterns. As a result, FQPCA is able to capture shifts in the scale and distribution of data that affect participant-level quantile curves, and is also a robust methodology suitable for dealing with outliers, heteroscedastic data or skewed data. The need for such methodology is exemplified by physical activity data collected using wearable devices. Participants often differ in the timing and intensity of physical activity behaviors, and capturing information beyond the participant-level expected value curves produced by FPCA is necessary for a robust quantification of diurnal patterns of activity. We illustrate our methods using accelerometer data from the National Health and Nutrition Examination Survey, and produce participant-level 10%, 50%, and 90% quantile curves over 24 h of activity. The proposed methodology is supported by simulation results, and is available as an R package., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. [br]For permissions, please e-mail: journals.permissions@oup.com.)

The National Heart, Lung, and Blood Institute convened a virtual workshop in September 2022 to discuss "Optimal Instruments for Measurement of Diet, Physical Activity, and Sleep." This report summarizes the proceedings, identifying current research gaps and future directions for measuring different lifestyle behaviors in adult population-based studies. Key discussions centered on integrating report-based methods, like questionnaires, with device-based assessments, including wearables and physiological measures such as biomarkers and omics to enhance self-reported metrics and better understand the underlying biologic mechanisms of chronic diseases. Emphasis was placed on the need for data harmonization, including the adoption of standard terminology, reproducible metrics, and accessible raw data, to enhance the analysis through artificial intelligence and machine learning techniques. The workshop highlighted the importance of standardizing procedures for integrated behavioral phenotypes using time-series data. These efforts aim to refine data accuracy and comparability across studies and populations, thereby advancing our understanding of lifestyle behaviors and their impact on chronic disease outcomes over the life course.

Background: Provoked anger is associated with an increased risk of cardiovascular disease events. The underlying mechanism linking provoked anger as well as other core negative emotions including anxiety and sadness to cardiovascular disease remain unknown. The study objective was to examine the acute effects of provoked anger, and secondarily, anxiety and sadness on endothelial cell health., Methods and Results: Apparently healthy adult participants (n=280) were randomized to an 8-minute anger recall task, a depressed mood recall task, an anxiety recall task, or an emotionally neutral condition. Pre-/post-assessments of endothelial health including endothelium-dependent vasodilation (reactive hyperemia index), circulating endothelial cell-derived microparticles (CD62E+, CD31+/CD42-, and CD31+/Annexin V+) and circulating bone marrow-derived endothelial progenitor cells (CD34+/CD133+/kinase insert domain receptor+ endothelial progenitor cells and CD34+/kinase insert domain receptor+ endothelial progenitor cells) were measured. There was a group×time interaction for the anger versus neutral condition on the change in reactive hyperemia index score from baseline to 40 minutes ( P =0.007) with a mean±SD change in reactive hyperemia index score of 0.20±0.67 and 0.50±0.60 in the anger and neutral conditions, respectively. For the change in reactive hyperemia index score, the anxiety versus neutral condition group by time interaction approached but did not reach statistical significance ( P =0.054), and the sadness versus neutral condition group by time interaction was not statistically significant ( P =0.160). There were no consistent statistically significant group×time interactions for the anger, anxiety, and sadness versus neutral condition on endothelial cell-derived microparticles and endothelial progenitor cells from baseline to 40 minutes., Conclusions: In this randomized controlled experimental study, a brief provocation of anger adversely affected endothelial cell health by impairing endothelium-dependent vasodilation.

Purpose: The purpose of this study was to examine whether engagement in health behaviors changed from pre-pandemic (2019) to during the pandemic (2020)., Methods: The combined 2019-2020 National Survey of Children's Health (NSCH) was used to inform this study. The NSCH is an annual survey designed to provide national estimates of key indicators of childhood health and well-being. Physical activity (number of days/week with >60 min of activity), screen-time (hours/day of TV viewing and computer use), and sleep (hours/day) were assessed by parental report. Adjusted binomial and multinomial logistic regression models were used to determine the association between survey year and health behaviors., Results: Children and adolescents were 36% more likely to be physically inactive in 2020 compared to 2019. Additionally, children and adolescents were 14% more likely to meet sleep guidelines and 39% less likely to meet screen-time guidelines in 2020 compared to 2019, independent of age, sex, race/ethnicity, and poverty level. Children (6-13 year) and adolescents (14-17 years) were 10% and 15% less likely to get below the recommended amount of sleep in 2020 compared to 2019, respectively., Conclusion: Prevalence of meeting sleep guidelines increased among children and adolescents in 2020 but decreased for physical activity and screen-time. Initiatives targeting activity and screen-time may be urgently needed. Whether rates of these health behaviors return to pre-pandemic levels over the next few years should be closely assessed., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Rest-activity rhythms (RARs), a measure of circadian rhythmicity in the free-living setting, are related to mortality risk, but evidence is limited on associations with cardiovascular disease (CVD) and its risk factors., Methods and Results: Participants included 4521 adults from the 2013 to 2014 National Health and Nutrition Examination Survey physical activity monitoring examination. Wrist-worn ActiGraph GT3X+ data were used to estimate RARs. Multivariable logistic models evaluated associations of RARs with prevalent CVD, hypertension, obesity, and central adiposity. Participants (mean age, 49 years) in the highest versus lowest tertile of relative amplitude (greater circadian rhythmicity) had 39% to 62% lower odds of prevalent CVD, hypertension, obesity, and central adiposity. A more active wake period was associated with 19% to 72% lower CVD, hypertension, obesity, and central adiposity odds. Higher interdaily stability (regular sleep-wake and rest-activity patterns) was related to 52% and 23% lower CVD and obesity odds, respectively. In contrast, participants in the highest versus lowest tertile of intradaily variability (fragmented RAR and inefficient sleep) had >3-fold and 24% higher CVD and obesity odds, respectively. A later and less restful sleep period was associated with 36% to 2-fold higher CVD, hypertension, obesity, and central adiposity odds. A statistically significant linear trend was observed for all associations ( P -trend<0.05)., Conclusions: A robust, stable, and less fragmented RAR, an active wake period, and an earlier and more restful sleep period are associated with lower prevalent CVD, hypertension, obesity, and central adiposity, with evidence of a dose-response relationship. The magnitude, timing, and regularity of sleep-wake and rest-activity patterns may be important targets for reducing cardiovascular risk.

Background: Growing evidence has implicated sedentary behavior is associated with cardiovascular and all-cause mortality, independent of moderate to vigorous physical activity (MVPA). Contrary to national physical activity guidelines, reductions in sedentary behavior are not promoted as a lifestyle modification in hypertensive adults. This may be in part because of a paucity of evidence demonstrating that sedentary behavior confers morbidity and mortality risk in hypertensive adults., Purpose: To examine the association between device-measured sedentary behavior and risk of cardiovascular and all-cause mortality and in hypertensive adults., Methods: Data for this analysis come from the 2003 to 2006 National Health and Nutrition Examination Survey, a nationally representative survey of US adults. Sedentary behavior and MVPA were assessed with an ActiGraph 7164 accelerometer. Hypertension was classified as blood pressure at least 140/≥90 mmHg or antihypertensive medication use., Results: Median follow-up was 14.5 years. After adjusting for covariates and MVPA, greater time spent in sedentary behavior was associated with an increased risk of cardiovascular mortality [quartile 1: REF, quartile 2: hazard ratio = 1.41 [95% confidence interval (95% CI) 0.83-2.38], quartile 3: hazard ratio = 1.25 (95% CI 0.81-1.94), quartile 4: hazard ratio = 2.14 (95% CI 1.41-3.24); P trend <0.001]. Greater sedentary behavior was also associated with an increased risk of all-cause mortality [quartile 1: REF: quartile 2: hazard ratio = 1.13 (95% CI 0.83-1.52), quartile 3: hazard ratio = 1.33 (95% CI 1.00-1.78), quartile 4: hazard ratio = 2.06 (95% CI 1.60, 2.64); P trend <0.001]., Conclusion: Greater sedentary behavior is associated with increased risk of cardiovascular mortality and all-cause mortality among US adults with hypertension. These findings suggest reductions in sedentary behavior should be considered to reduce mortality risk in hypertensive adults., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background There is limited evidence on the potential negative metabolic health impacts of prolonged and uninterrupted sedentary bouts in structurally disadvantaged youth. This study investigated associations between sedentary bout variables and metabolic health markers in the Hispanic Community Health Study/SOL Youth (Study of Latino Youth). Methods and Results SOL Youth was a population-based cohort of 1466 youth (age range, 8-16 years; 48.5% female); 957 youth were included in the analytic sample based on complete data. Accelerometers measured moderate-to-vigorous physical activity (MVPA), total sedentary time, and sedentary bout patterns (daily time spent in sedentary bouts ≥30 minutes, median sedentary bout duration, and number of daily breaks from sedentary time). Clinical measures included body mass index, waist circumference, fasting glucose, glycated hemoglobin, fasting insulin, and the homeostasis model assessment of insulin resistance. After adjusting for sociodemographics, total sedentary time, and MVPA, longer median bout durations and fewer sedentary breaks were associated with a greater body mass index percentile (b bouts =0.09 and b breaks =-0.18), waist circumference (b bouts =0.12 and b breaks =-0.20), and fasting insulin (b bouts =0.09 and b breaks =-0.21). Fewer breaks were also associated with a greater homeostasis model assessment of insulin resistance (b=-0.21). More time in bouts lasting ≥30 minutes was associated with a greater fasting glucose (b=0.18) and glycated hemoglobin (b=0.19). Conclusions Greater accumulation of sedentary time in prolonged and uninterrupted bouts had adverse associations with adiposity and glycemic control over and above total sedentary time and MVPA. Findings suggest interventions in Hispanic/Latino youth targeting both ends of the activity spectrum (more MVPA and less prolonged/uninterrupted sedentary patterns) may provide greater health benefits than those targeting only MVPA.

Background: Sedentary behavior is associated with an increased risk for adverse health outcomes, including cardiovascular disease (CVD), independent of physical activity status. Little is known about this relationship in an ethnically diverse population. The objective of our study is to assess the effects of leisure time and occupational sedentary behavior on multiple cardiovascular outcomes in a multi-ethnic cohort., Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) includes 2619 Caucasian, 1495 Hispanic, 1891 Black, and 804 Chinese-American adults aged 45-84 years and free of clinical CVD at enrollment, Sedentary behavior was self-reported at baseline. Participants were followed for an average of 13.6 years, and 14 types of cardiovascular outcomes were ascertained. Hazards of each cardiovascular outcome were modeled with adjustment for potential confounders, including physical activity., Results: Every one hour per day increase in leisure time sedentary behavior predicts a 6% increase in the adjusted hazards for CVD death ( P < 0.05). Every one hour increase in occupational sedentary time predicts a 21% and 20% decrease in the hazard for PVD and other revascularization, respectively ( P < 0.05)., Conclusions: Leisure time sedentary behavior was associated with increased hazards for CVD death, but occupational sedentary time appears to be protective of peripheral vascular disease and other revascularization., Condensed Abstract: Sedentary behavior has been consistently associated with an increased risk for adverse health outcomes, including cardiovascular disease (CVD), independent of physical activity status. The Multi-Ethnic Study of Atherosclerosis (MESA) consists of a racially and ethnically diverse cohort of adults age 45-84, free from CVD at baseline. Greater levels of leisure time sedentary behavior predicted increased hazards for PVD and CVD death after an average follow up of 13.6 years whereas occupational sedentary behaviors predicted reduced PVD. These results underscore the importance of reducing time spent sitting in addition to advocating for meeting physical activity targets across ethnicities.

We formulate the estimation of monotone response surface of multiple factors as the inverse of an iteration of partially ordered classifier ensembles. Each ensemble (called PIPE-classifiers) is a projection of Bayes classifiers on the constrained space. We prove the inverse of PIPE-classifiers (iPIPE) exists, and propose algorithms to efficiently compute iPIPE by reducing the space over which optimisation is conducted. The methods are applied in analysis and simulation settings where the surface dimension is higher than what the isotonic regression literature typically considers. Simulation shows iPIPE-based credible intervals achieve nominal coverage probability and are more precise compared to unconstrained estimation., Competing Interests: conflict of interest The authors have no conflicts of interest to disclose.

While prenatal screening and testing have expanded substantially over the past decade and provide access to more genetic information, expectant parents are more likely to describe the diagnosis experience as negative than positive. In addition, the conversations that take place during these experiences sometimes reflect unconscious bias against people with disabilities. Consequently, an interdisciplinary committee of experts, including people with disabilities, family members, disability organization leaders, healthcare and genetics professionals, and bioethicists, reviewed selected published and gray literature comparing the current state of the administration of prenatal testing to the ideal state. Subsequently, the interdisciplinary team created recommendations for clinicians, public health agencies, medical organizations, federal agencies, and other stakeholders involved with administering prenatal screening and testing to create better patient experiences; conduct training for healthcare professionals; create, enforce, and fund policies and guidelines; and engage in more robust data collection and research efforts., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Daily 24-h sleep-wake cycles have important implications for health, however researcher preferences in choice and location of wearable devices for behavior measurement can make 24-h cycles difficult to estimate. Further, missing data due to device malfunction, improper initialization, and/or the participant forgetting to wear one or both devices can complicate construction of daily behavioral compositions. The Method for Activity Sleep Harmonization (MASH) is a process that harmonizes data from two different devices using data from women who concurrently wore hip (waking) and wrist (sleep) devices for ≥ 4 days., Methods: MASH was developed using data from 1285 older community-dwelling women (ages: 60-72 years) who concurrently wore a hip-worn ActiGraph GT3X + accelerometer (waking activity) and a wrist-worn Actiwatch 2 device (sleep) for ≥ 4 days (N = 10,123 days) at the same time. MASH is a two-tiered process using (1) scored sleep data (from Actiwatch) or (2) one-dimensional convolutional neural networks (1D CNN) to create predicted wake intervals, reconcile sleep and activity data disagreement, and create day-level night-day-night pairings. MASH chooses between two different 1D CNN models based on data availability (ActiGraph + Actiwatch or ActiGraph-only). MASH was evaluated using Receiver Operating Characteristic (ROC) and Precision-Recall curves and sleep-wake intervals are compared before (pre-harmonization) and after MASH application., Results: MASH 1D CNNs had excellent performance (ActiGraph + Actiwatch ROC-AUC = 0.991 and ActiGraph-only ROC-AUC = 0.983). After exclusions (partial wear [n = 1285], missing sleep data proceeding activity data [n = 269], and < 60 min sleep [n = 9]), 8560 days were used to show the utility of MASH. Of the 8560 days, 46.0% had ≥ 1-min disagreement between the devices or used the 1D CNN for sleep estimates. The MASH waking intervals were corrected (median minutes [IQR]: -27.0 [-115.0, 8.0]) relative to their pre-harmonization estimates. Most correction (-18.0 [-93.0, 2.0] minutes) was due to reducing sedentary behavior. The other waking behaviors were reduced a median (IQR) of -1.0 (-4.0, 1.0) minutes., Conclusions: Implementing MASH to harmonize concurrently worn hip and wrist devices can minimizes data loss and correct for disagreement between devices, ultimately improving accuracy of 24-h compositions necessary for time-use epidemiology.

In this article we address the problem of estimating minimum effective doses in dose-finding clinical trials of multidimensional treatment. We are motivated by a behavioral intervention trial where we introduce sedentary breaks to subjects with a goal to reduce their glucose level monitored over 8 hours. Each sedentary break regimen is defined by two elements: break frequency and break duration. The trial aims to identify minimum combinations of frequency and duration that shift mean glucose, that is, the minimum effective dose (MED) combinations. The means of glucose reduction associated with the dose combinations are only partially ordered. To circumvent constrained estimation due to partial ordering, we propose estimating the MED by maximizing a weighted product of combinationwise posterior gains. The estimation adopts an asymmetric gain function, indexed by a decision parameter ϵ , which defines the relative gains of a true negative decision and a true positive decision. We also introduce an adaptive ϵ -tapering algorithm to be used in conjunction with the estimation method. Simulation studies show that using asymmetric gain with a carefully chosen ϵ is critical to keeping false discoveries low, while ϵ -tapering adds to the probability of identifying truly effective doses (i.e., true positives). Under an ensemble of scenarios for the sedentary break study, ϵ -tapering yields consistently high true positive rates across scenarios and achieves about 90% true positive rate, compared to 68% by a nonadaptive design with comparable false discovery rate.

Purpose of Review: Review the most recent evidence on the role of sedentary behavior in the prevention of cardiovascular disease (CVD)., Recent Findings: Prospective cohort studies continue to suggest a relationship between sedentary behavior and CVD, but the dose-response association, and the implications of sedentary pattern (vs. total volume) and context on CVD risk require further investigation. Most recent evidence suggests that physical activity influences the association between sedentary time and CVD risk, and that replacing sedentary time with other movement behaviors yields cardiometabolic benefits. Short-term intervention studies have further demonstrated that interrupting prolonged sitting with bouts of physical activity can elicit acute improvements on cardiometabolic biomarkers and vascular function relative to prolonged, uninterrupted sitting, albeit limited evidence exists on the long-term effects. More conclusive evidence regarding the implications of sedentary time on CVD risk is warranted before the optimal sedentary behavior reduction prescription for the prevention of CVD can be elucidated., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background and Purpose: We examined differences in the volume and pattern of physical activity (PA) and sedentary behavior between adults with and without stroke., Methods: We studied cohort members with an adjudicated or self-reported stroke (n=401) and age-, sex-, race-, region of residence-, and body mass index-matched participants without a history of stroke (n=1203) from the REGARDS study (Reasons for Geographic and Racial Differences in Stroke). Sedentary behavior (total volume and bouts), light-intensity PA, and moderate-to-vigorous-intensity PA were objectively measured for 7 days via hip-worn accelerometer., Results: Sedentary time (790.5±80.4 versus 752.4±81.9 min/d) and mean sedentary bout duration (15.7±12.6 versus 11.9±8.1 min/d) were higher and PA (light-intensity PA: 160.5±74.6 versus 192.9±73.5 min/d and moderate-to-vigorous-intensity PA: 9.0±11.9 versus 14.7±17.0 min/d) lower for stroke survivors compared with controls (P<0.001). Stroke survivors also accrued fewer activity breaks (65.5±21.9 versus 73.31±18.9 breaks/d) that were shorter (2.4±0.7 versus 2.7±0.8 minutes) and lower in intensity (188.4±60.8 versus 217.9±72.2 counts per minute) than controls (P<0.001)., Conclusions: Stroke survivors accrued a lower volume of PA, higher volume of sedentary time, and exhibited accrual patterns of more prolonged sedentary bouts and shorter, lower intensity activity breaks compared with persons without stroke.

Background: The association between accelerometer-assessed physical activity and risk of diabetes remains unclear, especially among US Hispanic/Latino adults who have lower levels of physical activity and a higher diabetes burden compared with other racial/ethnical populations in the country., Objectives: To examine the association between accelerometer-assessed physical activity and incident diabetes in a US Hispanic/Latino population., Methods: We included 7280 participants of the Hispanic Community Health Study/Study of Latinos who aged 18-74 y and free of diabetes at baseline. Data on moderate-to-vigorous physical activity (MVPA) were collected using a 7-d accelerometer measurement. Incident diabetes was assessed after a mean ± SD of 6.0 ± 0.8 y using standard procedures including blood tests. RRs and 95% CIs of diabetes associated with MVPA were estimated using survey Poisson regressions. The associations of MVPA with 6-y changes in adiposity measures were also examined., Results: A total of 871 incident cases of diabetes were identified. MVPA was inversely and nonlinearly associated with risk of diabetes (P-nonlinearity = 0.006), with benefits accruing rapidly at the lower end of MVPA range (<30 min/d) and leveling off thereafter. The association differed by population age (P-interaction = 0.006). Higher MVPA was associated with lower risk of diabetes among individuals older than 50 y (RRQ4 versus Q1 = 0.50; 95% CI: 0.35, 0.73; P-trend < 0.001) but not among younger individuals (RRQ4 versus Q1 = 0.98; 95% CI: 0.66, 1.47; P-trend = 0.92). An inverse association between MVPA and 6-y gain in waist circumference was also limited to the older group (P-interaction with age < 0.001)., Conclusions: Among US Hispanic/Latino adults, baseline accelerometer-derived MVPA was inversely associated with incident diabetes only among individuals aged 50 y and older. Further studies are needed to confirm our findings and to clarify potential mechanisms underlying the possible age differences in the MVPA-diabetes association. This study was registered at clinicaltrials.gov as NCT02060344., (Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.)

Endothelial dysfunction is a mechanism that may explain the link between prolonged sedentary time and cardiovascular disease. However, the relation between habitual sedentary behavior (SED) and endothelial function has yet to be explored., Purpose: The purpose of this study was to examine the association of accelerometer-measured SED with markers of endothelial cell health., Methods: Healthy adult participants (n=83; 43.4% male; 25.5 ± 5.8 years old) were examined. SED was measured for 7-days by accelerometer. Endothelial function measures included endothelium-dependent vasodilation (EDV); endothelial microparticles (EMPs) [CD62E+ and CD31+/CD42- EMPs]; and endothelial progenitor cells (EPCs) [CD34+/CD133+/KDR+ and CD34+/KDR+EPCs]. Participants were classified as having low or high SED based on a median split., Results: Participants in the low and high SED group spent a mean ± SD of 8.6 ± 1.1 and 11.1 ± 1.0 h/day in SED, respectively. No significant differences between the low and high SED groups were detected in mean [95% confidence interval (CI)] EDV (2.51 [2.21-2.81] vs. 2.36 [2.07-2.64], p =0.50), EMPs (CD62E+: 6.70 [6.55-6.84] vs. 6.56 [6.42-6.69], p =0.20; CD31+/CD42‒: 6.26 [6.10-6.42] vs. 6.18 [6.03-6.33], p =0.50), or EPCs (CD34+/KDR+: 11.91 [9.23-14.48]×10 -2 vs. 14.87 [12.41-17.32]×10 -2 , p =0.13); CD34+/CD133+/KDR+: 1.84 [1.28-2.39]×10 -2 vs. 2.17 [1.64-2.70]×10 -2 , p =0.43)., Conclusions: Among healthy adults, habitual SED was not associated with markers of endothelial cell health., Competing Interests: Disclosure of Interest: The authors report no conflict of interest. The results of the present study do not constitute endorsement by the American College of Sports Medicine.

It is unclear whether children with Down syndrome have differing physical activity and sedentary behavior levels compared to typical children. This study addressed this evidence gap in a national sample. Physical activity/sedentary behavior were ascertained by parental report. Findings highlighted that children with Down syndrome were less likely to engage in regular physical activity compared to typical children and had the lowest likelihood of regular physical activity among all subgroups with developmental disabilities/special healthcare needs. Children with Down syndrome were also more likely to watch high volumes of television compared to typical children, although this was nonsignificant upon adjustment for general health. It was concluded that children with Down syndrome are in urgent need for interventions/programs that promote physical activity.

Background: Experimental evidence suggests that sedentary time (ST) may contribute to cardiovascular disease by eliciting detrimental hemodynamic changes in the lower limbs. However, little is known about objectively measured ST and lower extremity peripheral artery disease (PAD)., Methods: We included 7,609 Hispanic/Latinos (ages 45-74) from the Hispanic Community Health Study/Study of Latinos. PAD was measured using the ankle brachial index (≤0.9). ST was measured using accelerometry. We used multivariable logistic regression to assess associations of quartiles of ST and PAD, and then used the same logistic models with restricted cubic splines to investigate continuous nonlinear associations of ST and PAD. Models were sequentially adjusted for traditional PAD risk factors, leg pain, and moderate- to vigorous-intensity physical activity (MVPA)., Results: Median ST was 12.2 h/d, and 5.4% of individuals had PAD. In fully adjusted restricted cubic splines models accounting for traditional PAD risk factors, leg pain, and MVPA, ST had a significant overall (P = .048) and nonlinear (P = .024) association with PAD. A threshold effect was seen such that time spent above median ST was associated with higher odds of PAD. That is, compared to median ST, 1, 2, and 3 hours above median ST were associated with a PAD odds ratio of 1.16 (95% CI = 1.02-1.31), 1.44 (1.06-1.94), and 1.80 (1.11-2.90), respectively., Conclusions: Among Hispanic/Latino adults, ST was associated with higher odds of PAD, independent of leg pain, MVPA, and traditional PAD risk factors. Notably, we observed a threshold effect such that these associations were only observed at the highest levels of ST., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To examine the dose-response associations between accelerometer assessed total physical activity, different intensities of physical activity, and sedentary time and all cause mortality., Design: Systematic review and harmonised meta-analysis., Data Sources: PubMed, PsycINFO, Embase, Web of Science, Sport Discus from inception to 31 July 2018., Eligibility Criteria: Prospective cohort studies assessing physical activity and sedentary time by accelerometry and associations with all cause mortality and reported effect estimates as hazard ratios, odds ratios, or relative risks with 95% confidence intervals., Data Extraction and Analysis: Guidelines for meta-analyses and systematic reviews for observational studies and PRISMA guidelines were followed. Two authors independently screened the titles and abstracts. One author performed a full text review and another extracted the data. Two authors independently assessed the risk of bias. Individual level participant data were harmonised and analysed at study level. Data on physical activity were categorised by quarters at study level, and study specific associations with all cause mortality were analysed using Cox proportional hazards regression analyses. Study specific results were summarised using random effects meta-analysis., Main Outcome Measure: All cause mortality., Results: 39 studies were retrieved for full text review; 10 were eligible for inclusion, three were excluded owing to harmonisation challenges (eg, wrist placement of the accelerometer), and one study did not participate. Two additional studies with unpublished mortality data were also included. Thus, individual level data from eight studies (n=36 383; mean age 62.6 years; 72.8% women), with median follow-up of 5.8 years (range 3.0-14.5 years) and 2149 (5.9%) deaths were analysed. Any physical activity, regardless of intensity, was associated with lower risk of mortality, with a non-linear dose-response. Hazards ratios for mortality were 1.00 (referent) in the first quarter (least active), 0.48 (95% confidence interval 0.43 to 0.54) in the second quarter, 0.34 (0.26 to 0.45) in the third quarter, and 0.27 (0.23 to 0.32) in the fourth quarter (most active). Corresponding hazards ratios for light physical activity were 1.00, 0.60 (0.54 to 0.68), 0.44 (0.38 to 0.51), and 0.38 (0.28 to 0.51), and for moderate-to-vigorous physical activity were 1.00, 0.64 (0.55 to 0.74), 0.55 (0.40 to 0.74), and 0.52 (0.43 to 0.61). For sedentary time, hazards ratios were 1.00 (referent; least sedentary), 1.28 (1.09 to 1.51), 1.71 (1.36 to 2.15), and 2.63 (1.94 to 3.56)., Conclusion: Higher levels of total physical activity, at any intensity, and less time spent sedentary, are associated with substantially reduced risk for premature mortality, with evidence of a non-linear dose-response pattern in middle aged and older adults., Systematic Review Registration: PROSPERO CRD42018091808., Competing Interests: Competing interests: All authors have completed the ICMJE uniform disclosure form and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objective: The purpose of this study, which used mobile technologies to continuously collect data for 1 year, was to examine the association of psychological stress with objectively measured sedentary behavior in adults at both the group (e.g., nomothetic approach) and individual (e.g., idiographic approach) level., Methods: Data were collected in an observational study of healthy adults (n = 79) residing in the New York City metro area who were studied for 365 days from 2014 to 2015. Sedentary behavior was objectively measured via accelerometry. A smartphone-based electronic diary was used to assess level of stress ("Overall, how stressful was your day?" 0-10 scale) and sources of stress., Results: The end-of-day stress rating was not associated with total sedentary time (B = -1.34, p = .767) at the group level. When specific sources of stress were evaluated at the group level, argument-related stress was associated with increased sedentariness, whereas running late- and work-related stress were associated with decreased sedentariness. There was a substantial degree of interindividual variability in the relationship of stress with sedentary behavior. Both the level and sources of stress were associated with increased sedentariness for some, decreased sedentariness for others, and had no effect for many (within-person variance p < .001)., Conclusions: These findings suggest that the influence of stress on sedentary behavior varies by source of stress and from person to person. A precision medicine approach may be warranted to target reductions in sedentary time, although further studies are needed to confirm the observed findings in light of study limitations including a small sample size and enrollment of participants from a single, urban metropolitan area.

Psychological stress is a major contributor to the adoption of unhealthy behaviors, which in turn accounts for 41% of global cardiovascular disease burden. While the proliferation of mobile health apps has offered promise to stress management, these apps do not provide micro-level feedback with regard to how to adjust one's behaviors to achieve a desired health outcome. In this paper, we formulate the task of multi-stage stress management as a sequential decision-making problem and explore the application of reinforcement learning to provide micro-level feedback for stress reduction. Specifically, we incorporate a multi-stage threshold selection into Q-learning to derive an interpretable form of a recommendation policy for behavioral coaching. We apply this method on an observational dataset that contains Fitbit ActiGraph measurements and self-reported stress levels. The estimated policy is then used to understand how exercise patterns may affect users' psychological stress levels and to perform coaching more effectively.

Background: Excessive sedentary time is ubiquitous in developed nations and is associated with deleterious health outcomes. Few studies have examined whether the manner in which sedentary time is accrued (in short or long bouts) carries any clinical relevance. The purpose of this study was to examine the association of prolonged, uninterrupted sedentary behavior with glycemic biomarkers in a cohort of US Hispanic/Latino adults., Methods: We studied 12 083 participants from the HCHS/SOL (Hispanic Community Health Study/Study of Latinos), a population-based study of Hispanic/Latino adults 18 to 74 years of age. Homeostatic model assessment of insulin resistance and glycosylated hemoglobin were measured from a fasting blood sample, and 2-hour glucose was measured after an oral glucose tolerance test. Sedentary time was objectively measured with a hip-mounted accelerometer. Prolonged, uninterrupted sedentariness was expressed as mean sedentary bout length., Results: After adjustment for potential confounders and moderate to vigorous physical activity, longer sedentary bout duration was dose-dependently associated with increased homeostatic model assessment of insulin resistance ( P for trend<0.001) and 2-hour glucose levels ( P for trend=0.015). These associations were not independent of total sedentary time; however, a significant interaction between sedentary bout duration and total sedentary time was observed. Evaluation of the joint association of total sedentary time and sedentary bout duration showed that participants in the upper quartile for both sedentary characteristics (ie, high total sedentary time and high sedentary bout duration) had the highest levels of homeostatic model assessment of insulin resistance ( P <0.001 versus low group for both sedentary characteristics) and 2-hour glucose ( P =0.002 versus low group for both sedentary characteristics). High total sedentary time or high sedentary bout duration alone were not associated with differences in any glycemic biomarkers., Conclusions: Accruing sedentary time in prolonged, uninterrupted bouts may be deleteriously associated with biomarkers of glucose regulation., (© 2017 American Heart Association, Inc.)

Background: Excessive sedentary time is ubiquitous in Western societies. Previous studies have relied on self-reporting to evaluate the total volume of sedentary time as a prognostic risk factor for mortality and have not examined whether the manner in which sedentary time is accrued (in short or long bouts) carries prognostic relevance., Objective: To examine the association between objectively measured sedentary behavior (its total volume and accrual in prolonged, uninterrupted bouts) and all-cause mortality., Design: Prospective cohort study., Setting: Contiguous United States., Participants: 7985 black and white adults aged 45 years or older., Measurements: Sedentary time was measured using a hip-mounted accelerometer. Prolonged, uninterrupted sedentariness was expressed as mean sedentary bout length. Hazard ratios (HRs) were calculated comparing quartiles 2 through 4 to quartile 1 for each exposure (quartile cut points: 689.7, 746.5, and 799.4 min/d for total sedentary time; 7.7, 9.6, and 12.4 min/bout for sedentary bout duration) in models that included moderate to vigorous physical activity., Results: Over a median follow-up of 4.0 years, 340 participants died. In multivariable-adjusted models, greater total sedentary time (HR, 1.22 [95% CI, 0.74 to 2.02]; HR, 1.61 [CI, 0.99 to 2.63]; and HR, 2.63 [CI, 1.60 to 4.30]; P for trend < 0.001) and longer sedentary bout duration (HR, 1.03 [CI, 0.67 to 1.60]; HR, 1.22 [CI, 0.80 to 1.85]; and HR, 1.96 [CI, 1.31 to 2.93]; P for trend < 0.001) were both associated with a higher risk for all-cause mortality. Evaluation of their joint association showed that participants classified as high for both sedentary characteristics (high sedentary time [≥12.5 h/d] and high bout duration [≥10 min/bout]) had the greatest risk for death., Limitation: Participants may not be representative of the general U.S. population., Conclusion: Both the total volume of sedentary time and its accrual in prolonged, uninterrupted bouts are associated with all-cause mortality, suggesting that physical activity guidelines should target reducing and interrupting sedentary time to reduce risk for death., Primary Funding Source: National Institutes of Health.

Purpose: Systemic inflammation, measured by C-reactive protein (CRP), is an important risk factor for cardiovascular disease (CVD) and mortality. We investigated whether aerobic exercise training (AEXT) affects African Americans with high inflammation (HI) the same way it does African Americans with low inflammation (LI) in terms of CVD risk factors., Methods: 23 African Americans with CRP levels <3 mg/L (LI) and 14 African Americans with CRP ≥3 mg/L (HI) underwent six months of AEXT. Participants were sedentary, non-diabetic, non-smoking, with clinical blood pressure <160/100 mm Hg, were non-hyperlipidemic, had no signs of cardiovascular, renal, or pulmonary disease, and were not on medication. Measures included CD62E+ endothelial microparticles (EMPs), a measure of early stage endothelial dysfunction, as well as lipid and glucose profile, aerobic fitness, body composition, and blood pressure., Results: The LI group improved aerobic fitness by 10%, body mass index by 3%, and plasma triglycerides by 20%, with no change being observed in HI group for these variables. The HI group improved fasting plasma glucose levels by 10%, with no change occurring in the LI group. Both groups improved CD62E+ EMPs by 38% and 59% for the LI and HI group, respectively., Conclusions: A standard AEXT intervention differentially affected CVD risk factors among African Americans with high and low inflammation. This may indicate that, in African Americans with high inflammation, AEXT alone may not be enough to reap the same benefits as their low-inflammation peers in terms of CVD risk modification., Competing Interests: Competing Interests: None declared.

There is limited empirical evidence to support the protective effects of physical activity in the prevention of hypertension among African Americans. The purpose of this study was to examine the association of physical activity with incident hypertension among African Americans. We studied 1311 participants without hypertension at baseline enrolled in the Jackson Heart Study, a community-based study of African Americans residing in Jackson, Mississippi. Overall physical activity, moderate-vigorous physical activity, and domain-specific physical activity (work, active living, household, and sport/exercise) were assessed by self-report during the baseline examination (2000-2004). Incident hypertension, assessed at examination 2 (2005-2008) and examination 3 (2009-2013), was defined as the first visit with systolic/diastolic blood pressure ≥140/90 mm Hg or self-reported antihypertensive medication use. Over a median follow-up of 8.0 years, there were 650 (49.6%) incident hypertension cases. The multivariable-adjusted hazard ratios (95% confidence interval) for incident hypertension comparing participants with intermediate and ideal versus poor levels of moderate-vigorous physical activity were 0.84 (0.67-1.05) and 0.76 (0.58-0.99), respectively ( P trend=0.038). A graded, dose-response association was also present for sport/exercise-related physical activity (Quartiles 2, 3, and 4 versus Quartile 1: 0.92 [0.68-1.25], 0.87 [0.67-1.13], 0.75 [0.58-0.97], respectively; P trend=0.032). There were no statistically significant associations observed for overall physical activity, or work, active living, and household-related physical activities. In conclusion, the results of the current study suggest that regular moderate-vigorous physical activity or sport/exercise-related physical activity may reduce the risk of developing hypertension in African Americans., Competing Interests: Conflicts of Interest/Disclosures: None., (© 2017 American Heart Association, Inc.)

Objectives: The understanding of how stress influences health behavior can provide insights into developing healthy lifestyle interventions. This understanding is traditionally attained through observational studies that examine associations at a population level. This nomothetic approach, however, is fundamentally limited by the fact that the environment- person milieu that constitutes stress exposure and experience can vary substantially between individuals, and the modifiable elements of these exposures and experiences are individual-specific. With recent advances in smartphone and sensing technologies, it is now possible to conduct idiographic assessment in users' own environment, leveraging the full-range observations of actions and experiences that result in differential response to naturally occurring events. The aim of this paper is to explore the hypothesis that an ideographic N-of-1 model can better capture an individual's stress- behavior pathway (or the lack thereof) and provide useful person-specific predictors of exercise behavior., Methods: This paper used the data collected in an observational study in 79 participants who were followed for up to a 1-year period, wherein their physical activity was continuously and objectively monitored by actigraphy and their stress experience was recorded via ecological momentary assessment on a mobile app. In addition, our analyses considered exogenous and environmental variables retrieved from public archive such as day in a week, daylight time, temperature and precipitation. Leveraging the multiple data sources, we developed prediction algorithms for exercise behavior using random forest and classification tree techniques using a nomothetic approach and an N-of-1 approach. The two approaches were compared based on classification errors in predicting personalized exercise behavior., Results: Eight factors were selected by random forest for the nomothetic decision model, which was used to predict whether a participant would exercise on a particular day. The predictors included previous exercise behavior, emotional factors (e.g., midday stress), external factors such as weather (e.g., temperature), and self-determination factors (e.g., expectation of exercise). The nomothetic model yielded an average classification error of 36%. The ideographic N-of-1 models used on average about two predictors for each individual, and had an average classification error of 25%, which represented an improvement of 11 percentage points., Conclusions: Compared to the traditional one-size-fits-all, nomothetic model that generalizes population-evidence for individuals, the proposed N-of-1 model can better capture the individual difference in their stressbehavior pathways. In this paper, we demonstrate it is feasible to perform personalized exercise behavior prediction, mainly made possible by mobile health technology and machine learning analytics., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Schattauer GmbH.)

Purpose: The purposes of this study were to examine patterns of objectively measured sedentary behavior in a national cohort of US middle-age and older adults and to determine factors that influence prolonged sedentary behavior., Methods: We studied 8096 participants from the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a population-based study of black and white adults 45 yr or older. Seven-day accelerometry was conducted. Prolonged sedentary behavior was defined as accumulating 50% or more of total sedentary time in bouts of 30 min or greater., Results: The number of sedentary bouts greater than or equal to 20, 30, 60, and 90 min were 8.8 ± 2.3, 5.5 ± 1.9, 1.9 ± 1.1, and 0.8 ± 0.7 bouts per day, respectively. Sedentary bouts greater than or equal to 20, 30, 60, and 90 min accounted for 60.0% ± 13.9%, 48.0% ± 15.5%, 26.0% ± 15.4%, and 14.2% ± 12.9% of total sedentary time, respectively. Several factors were associated with prolonged sedentary behavior in multivariate-adjusted models (odds ratio [95% confidence interval]): older age (65-74 yr: 1.99 [1.55-2.57]; 75 yr or older: 4.68 [3.61-6.07] vs 45-54 yr), male sex (1.41 [1.28-1.56] vs female), residence in nonstroke belt/buckle region of the United States (stroke belt: 0.87 [0.77-0.98]; stroke buckle: 0.86 [0.77-0.95] vs non-belt/buckle), body mass index (BMI) (overweight: 1.33 [1.18-1.51]; obese: 2.15 [1.89-2.44] vs normal weight), winter (1.18 [1.03-1.35] vs summer), and low amounts of moderate-to-vigorous physical activity (MVPA) [0 min·wk: 2.00 [1.66-2.40] vs ≥150 min·wk)., Conclusions: In this sample of US middle-age and older adults, a large proportion of total sedentary time was accumulated in prolonged, uninterrupted bouts of sedentary behavior as almost one-half was accumulated in sedentary bouts greater than or equal to 30 min. Several sociodemographic (age, sex, and BMI), behavioral (MVPA), environmental (region), and seasonal factors are associated with patterns of prolonged sedentary behavior.

The manner in which the circulation accommodates each heartbeat may underlie blood pressure (BP) variability. We used the Ambulatory Arterial Stiffness Index (AASI), which reflects this ventricular-vascular interaction, in untreated individuals with prehypertension and Stage 1 hypertension to evaluate two different measures of BP variability using the brachial pulse pressure (PP) obtained over 24 hours. We enrolled 64 untreated adults with systolic BP between 130-159 mm Hg and diastolic values of <100 mm Hg who underwent 24-hour ambulatory BP monitoring with calculation of 24-hour AASIs. Variability in brachial PP was determined using the standard deviation of the measurements over 24 hours and the average real variability. The 24-hour AASI correlated with both measures of 24-hour PP variability (P < .001 for both). Subdividing the 24-hour stiffness index into daytime and nighttime components showed modest differences in their relationship to PP variability, with the daytime being significantly different from 24-hour AASI and the standard deviation of the brachial PP consistently having a higher correlation to the AASI when compared with the average real variability. These observations may be useful to understand differences in variability measures of BP measurements, such as PP, to measures like the AASI as reported in longitudinal studies., (Copyright © 2015 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)

Ambulatory blood pressure monitoring (ABPM) can be used to identify white coat hypertension and guide hypertensive treatment. We determined the percentage of ABPM claims submitted between 2007 and 2010 that were reimbursed. Among 1970 Medicare beneficiaries with submitted claims, ABPM was reimbursed for 93.8% of claims that had an International Classification of Diseases, Ninth Revision, diagnosis code of 796.2 ("elevated blood pressure reading without diagnosis of hypertension") versus 28.5% of claims without this code. Among claims without an International Classification of Diseases, Ninth Revision, diagnosis code of 796.2 listed, those for the component (eg, recording, scanning analysis, physician review, reporting) versus full ABPM procedures and performed by institutional versus non-institutional providers were each more than two times as likely to be successfully reimbursed. Of the claims reimbursed, the median payment was $52.01 (25th-75th percentiles, $32.95-$64.98). In conclusion, educating providers on the ABPM claims reimbursement process and evaluation of Medicare reimbursement may increase the appropriate use of ABPM and improve patient care., (Copyright © 2014 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)

The US Centers for Medicaid and Medicare Services reimburses ambulatory blood pressure monitoring (ABPM) for suspected white coat hypertension. We estimated ABPM use between 2007 and 2010 among a 5% random sample of Medicare beneficiaries (≥65 years). In 2007, 2008, 2009, and 2010, the percentage of beneficiaries with ABPM claims was 0.10%, 0.11%, 0.10%, and 0.09%, respectively. A prior diagnosis of hypertension was more common among those with versus without an ABPM claim (77.7% vs. 47.0%). Among hypertensive beneficiaries, 95.2% of those with an ABPM claim were taking antihypertensive medication. Age 75-84 versus 65-74 years, having coronary heart disease, having chronic kidney disease, having multiple prior hypertension diagnoses, and having filled multiple classes of antihypertensive medication were associated with an increased odds for an ABPM claim among hypertensive beneficiaries. ABPM use was very low among Medicare beneficiaries and was not primarily used for diagnosing white coat hypertension in untreated individuals., (Copyright © 2014 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)

We investigated the relationship between renal function, blood pressure variability (BPV), and nitric oxide (NO) in a group of African Americans with normal or mildly impaired renal function. 24-hour ambulatory blood pressure monitoring was performed, NO measured, and glomerular filtration rate (GFR) calculated in 38 African Americans. Participants were categorized as having normal (GFR > 90 mL/min per 1.73 m(2)) or mildly impaired (GFR 60-89 mL/min per 1.73 m(2)) renal function. Diastolic BPV was significantly lower in the mildly impaired renal function group. Regression analyses revealed a significant positive association between GFR and diastolic BPV for the entire study group. Plasma NO levels were significantly higher in the mildly impaired renal function group and negatively correlated with diastolic BPV. In conclusion, diastolic BPV was reduced in African Americans with mildly impaired renal function, which may be the result of increased NO production. These results conflict with previous findings in diseased and nonblack populations and could provide rationale for studying BPV early in the disease state when BP-buffering mechanisms are still preserved.