Physiology of sedentary behavior.

Sedentary behaviors (SB) are characterized by low energy expenditure while in a sitting or reclining posture. Evidence relevant to understanding the physiology of SB can be derived from studies employing several experimental models: bed rest, immobilization, reduced step count, and reducing/interrupting prolonged SB. We examine the relevant physiological evidence relating to body weight and energy balance, intermediary metabolism, cardiovascular and respiratory systems, the musculoskeletal system, the central nervous system, and immunity and inflammatory responses. Excessive and prolonged SB can lead to insulin resistance, vascular dysfunction, shift in substrate use toward carbohydrate oxidation, shift in muscle fiber from oxidative to glycolytic type, reduced cardiorespiratory fitness, loss of muscle mass and strength and bone mass, and increased total body fat mass and visceral fat depot, blood lipid concentrations, and inflammation. Despite marked differences across individual studies, longer term interventions aimed at reducing/interrupting SB have resulted in small, albeit marginally clinically meaningful, benefits on body weight, waist circumference, percent body fat, fasting glucose, insulin, HbA1c and HDL concentrations, systolic blood pressure, and vascular function in adults and older adults. There is more limited evidence for other health-related outcomes and physiological systems and for children and adolescents. Future research should focus on the investigation of molecular and cellular mechanisms underpinning adaptations to increasing and reducing/interrupting SB and the necessary changes in SB and physical activity to impact physiological systems and overall health in diverse population groups.

Leisure Sedentary Behavior, Physical Activities, and Cardiovascular Disease Among Individuals With Metabolic Dysfunction-Associated Fatty Liver Disease.

BACKGROUND: Metabolic dysfunction-associated fatty liver disease is a significant risk factor for cardiovascular disease (CVD). This study assesses the association between leisure-time physical activity, sedentary behavior, and CVD risk among patients with metabolic dysfunction-associated fatty liver disease, considering genetic predisposition to CVD. METHODS: This cohort study included 157 794 participants with metabolic dysfunction-associated fatty liver disease from the UK Biobank who were free of CVD at baseline. The study measured leisure-time sedentary behaviors (watching TV, using a computer, and driving) and physical activities (walking for pleasure, light and heavy do-it-yourself activities, strenuous sports, and other exercises) in terms of frequency and duration over the 4 weeks before assessment. Both a Cox proportional hazard model and an isotemporal substitution model were utilized in the study to assess the association between leisure sedentary behavior, physical activities, and CVD risk. RESULTS: During a median 12.5 years of follow-up, 26 355 CVD cases were reported, including 19 746 coronary heart disease, 4836 stroke, and 7398 heart failure cases. High physical activity levels were linked to a significantly lower risk of CVD (21%), coronary heart disease (20%), stroke (15%), and heart failure (31%). In contrast, individuals with >6.5 h/d of sedentary behavior faced a 16% to 21% higher risk of these conditions compared with those with ≤3.5 h/d. Notably, replacing 30 minutes of inactivity with physical activity reduced CVD risks by 3% to 16%, particularly with strenuous sports. A significant interaction was observed between physical activity, sedentary behavior, and genetic predisposition in relation to stroke risk. CONCLUSIONS: Among patients with metabolic dysfunction-associated fatty liver disease, higher leisure-time physical activity levels correlate with reduced CVD risks, while increased sedentary behavior is linked to higher CVD risks. Replacing sedentary time with physical activity consistently shows benefits in reducing CVD outcomes, irrespective of genetic predisposition.

The causal relationship between physical activity, sedentary behavior and brain cortical structure: a Mendelian randomization study.

Physical activity and sedentary behavior, both distinct lifestyle behaviors associated with brain health, have an unclear potential relationship with brain cortical structure. This study aimed to determine the causal link between physical activity, sedentary behavior, and brain cortical structure (cortical surface area and thickness) through Mendelian randomization analysis. The inverse-variance weighted method was primarily utilized, accompanied by sensitivity analyses, to confirm the results' robustness and accuracy. Analysis revealed nominally significant findings, indicating a potential positive influence of physical activity on cortical thickness in the bankssts (ß = 0.002 mm, P = 0.043) and the fusiform (ß = 0.002 mm, P = 0.018), and a potential negative association of sedentary behavior with cortical surface area in the caudal middle frontal (ß = -34.181 mm2, P = 0.038) and the pars opercularis (ß = -33.069 mm2, P = 0.002), alongside a nominally positive correlation with the cortical surface area of the inferior parietal (ß = 58.332 mm2, P = 0.035). Additionally, a nominally significant negative correlation was observed between sedentary behavior and cortical thickness in the paracentral (ß = -0.014 mm, P = 0.042). These findings offer insights into how lifestyle behaviors may influence brain cortical structures, advancing our understanding of their interaction with brain health.

Sedentary time associates detrimentally and physical activity beneficially with metabolic flexibility in adults with metabolic syndrome.

Metabolic flexibility (MetFlex) describes the ability to respond and adapt to changes in metabolic demand and substrate availability. The relationship between physical (in)activity and MetFlex is unclear. This study aimed to determine whether sedentary time, physical activity (PA), and cardiorespiratory fitness associate with MetFlex. Sedentary time, standing, and PA were measured with accelerometers for 4 weeks in 64 sedentary adults with metabolic syndrome [37 women, 27 men; 58.3 (SD 6.8) years]. Fitness (V̇o2max; mL·kg-1·min-1) was measured with graded maximal cycle ergometry. MetFlex was assessed with indirect calorimetry as the change in respiratory exchange ratio (ΔRER) from fasting to insulin stimulation with hyperinsulinemic-euglycemic clamp and from low-intensity to maximal exercise. Carbohydrate (CHOox) and fat oxidation (FATox) were calculated from respiratory gases. High sedentary time associated with higher fasting RER [ß = 0.35 (95% confidence interval: 0.04, 0.67)], impaired insulin-stimulated MetFlex (ΔRER) [ß=-0.41 (-0.72, -0.09)], and lower fasting FATox [ß=-0.36 (-0.67, -0.04)]. Standing associated with lower fasting RER [ß=-0.32 (-0.62, -0.02)]. Higher standing time and steps/day associated with higher fasting FATox [ß = 0.31 (0.01, 0.61), and ß = 0.26 (0.00, 0.53)]. Light-intensity and total PA associated with better insulin-stimulated MetFlex [ß = 0.33 (0.05, 0.61)], and ß = 0.33 (0.05, 0.60)]. Higher V̇o2max associated with higher CHOox during maximal exercise [ß = 0.81 (0.62, 1.00)], as well as during insulin stimulation [ß = 0.43 (0.13, 0.73)]. P values are less than 0.05 for all associations. Sedentary time and PA associate with MetFlex. Reducing sitting and increasing PA of even light intensity might aid in the prevention of metabolic diseases in risk populations through their potential effects on energy metabolism.NEW & NOTEWORTHY High accelerometer-assessed sedentary time associates with metabolic inflexibility measured during hyperinsulinemic-euglycemic clamp in adults with metabolic syndrome, and more light-intensity and total physical activity associate with more metabolic flexibility. Physical activity behaviors may thus play an important role in the regulation of fuel metabolism. This highlights the potential of reduced sedentary time and increased physical activity of any intensity to induce metabolic health benefits and help in disease prevention in risk populations.

Study Design and Protocol of the Multisite Pregnancy 24/7 Cohort Study.

Hypertensive disorders of pregnancy and other adverse pregnancy outcomes (APOs) are associated with an increased risk of future maternal cardiovascular disease. Physical activity during pregnancy reduces the risk of these APOs, yet few meet physical activity guidelines during pregnancy. Little is known about the role of sedentary behavior or sleep in APOs, a critical gap in knowledge given these behaviors comprise the majority of a 24-hour day. To address this knowledge gap, the Pregnancy 24/7 cohort study (2020-2025) uses 2 devices for 24-hour activity assessment in each trimester of pregnancy to examine associations of sedentary behavior, sleep, and the 24-hour activity cycle (composition of sedentary behavior, physical activity, and sleep) with hypertensive disorders and other APOs. Participants (n = 500) are recruited from the University of Iowa, University of Pittsburgh, and West Virginia University in early pregnancy and followed through delivery. The activPAL3 micro and Actiwatch Spectrum Plus are worn in each trimester for 7 days of 24-hour wear to assess the 24-hour activity cycle. APOs are abstracted from medical charts. This study will provide critical data to fuel future research examining how modifying the 24-hour activity cycle in pregnancy can improve maternal health.

Replacement of sedentary behavior with various physical activities and the risk of all-cause and cause-specific mortality.

BACKGROUND: Sedentary behavior (SB) has emerged as a significant health concern that deserves attention. This study aimed to examine the associations between prolonged sedentary behavior and the risk of all-cause and cause-specific mortality as well as to explore desirable alternatives to sitting in terms of physical activity (PA). METHODS: Two prospective cohort investigations were conducted using the UK Biobank and NHANES datasets, with a total of 490,659 and 33,534 participants, respectively. Cox proportional hazards regression models were used to estimate the associations between SB and the risk of all-cause and cause-specific mortality due to cancer, cardiovascular disease (CVD), respiratory diseases, and digestive diseases. In addition, we employed isotemporal substitution models to examine the protective effect of replacing sitting with various forms of PA. RESULTS: During the average follow-up times of 13.5 and 6.7 years, 36,109 and 3057 deaths were documented in the UK Biobank and NHANES, respectively. Both cohorts demonstrated that, compared with individuals sitting less than 5 h per day, individuals with longer periods of sitting had higher risks of all-cause and cause-specific mortality due to cancer, CVD, and respiratory diseases but not digestive diseases. Moreover, replacing SB per day with PA, even substituting 30 min of walking for pleasure, reduced the risk of all-cause mortality by 3.5% (hazard ratio [HR] 0.965, 95% confidence interval [CI] 0.954-0.977), whereas cause-specific mortality from cancer, CVD, and respiratory diseases was reduced by 1.6% (HR 0.984, 95% CI 0.968-1.000), 4.4% (HR 0.956, 95% CI 0.930-0.982), and 15.5% (HR 0.845, 95% CI 0.795-0.899), respectively. Furthermore, the protective effects of substitution became more pronounced as the intensity of exercise increased or the alternative duration was extended to 1 h. CONCLUSIONS: SB was significantly correlated with substantially increased risks of all-cause mortality and cause-specific mortality from cancer, CVD, and respiratory diseases. However, substituting sitting with various forms of PA, even for short periods involving relatively light and relaxing physical activity, effectively reduced the risk of both overall and cause-specific mortality.

Replacing device-measured sedentary time with physical activity is associated with lower risk of coronary heart disease regardless of genetic risk.

BACKGROUND: Excess sedentary time (ST) is recognized as an important modifiable risk factor for coronary heart disease (CHD). However, whether the associations of genetic susceptibility with CHD incidence can be modified by replacing wearable-device-measured ST with physical activity (PA) is unknown. OBJECTIVES: To examine the associations of wearable-device-measured ST replaced by PA with incident CHD across strata of genetic susceptibility. METHODS: This study included 77,500 White British (57% female) with valid wrist-worn accelerometry and without prevalent CHD/stroke from UK Biobank. Genetic susceptibility to CHD was quantified through weighted polygenic risk scores for CHD based on 300 single-nucleotide polymorphisms. Wrist-worn accelerometer data were used to derive ST, light PA, and moderate-to-vigorous PA (MVPA). RESULTS: Reallocation of 60 min/day of ST into the same amount of MVPA was associated with approximately 9% lower relative risk of CHD for all participants and across strata of genetic risk: replacement of 1 min/day of ST associated with <1% lower relative risk of CHD. No evidence of interaction (p: 0.784) was found between genetic risk and ST for CHD risk. Reallocating 60 min/day of ST into the same MVPA time was associated with greater absolute CHD risk reductions at high genetic risk (0.27%) versus low genetic risk (0.15%). CONCLUSIONS: Replacing any amount of ST with an equal amount of MVPA time is associated with a lower relative risk of CHD, irrespective of genetic susceptibility to CHD. Reductions in CHD absolute risk for replacing ST with MVPA are greater at high genetic risk versus low genetic risk.

Placental structural adaptation to maternal physical activity and sedentary behavior: findings of the DALI lifestyle study.

STUDY QUESTION: Are maternal levels of moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) in obese pregnant women associated with placental structural adaptations for facilitating oxygen delivery to the fetus? SUMMARY ANSWER: Higher maternal MVPA and ST are associated with a higher density of villi, a proxy measure of placental surface area for oxygen delivery to the fetus, without further added placental vessels. WHAT IS KNOWN ALREADY: Physical activity during pregnancy intermittently reduces uterine blood flow, potentially limiting placental and fetal oxygen supply. The placenta can mount several adaptive responses, including enlargement of the surface area of villi and/or feto-placental vessels to accommodate fetal needs. Early research on the morphology and growth of the placenta with exercise interventions has shown inconsistencies and is lacking, particularly in non-lean pregnant women. STUDY DESIGN, SIZE, DURATION: This study is a secondary longitudinal analysis of the vitamin D and lifestyle intervention for gestational diabetes prevention (DALI) randomized controlled trial. The prospective study was conducted between 2012 and 2015 in nine European countries at 11 different sites. In this analysis, 92 pregnant women with a BMI ≥ 29 kg/m2 were combined into one cohort. PARTICIPANTS/MATERIALS, SETTING, METHODS: MVPA and percentage of time spent sedentary (% ST) were measured with accelerometers during gestation. Placental sections were immunostained for endothelial cell-specific CD34. Artificial intelligence (AI)-based stereology assessed villous density, number, and cross-sectional area of vessels on whole-slide images and in selected regions comprising peripheral villi only, where the majority of vascular adaptations occur. Expression of pro- and anti-angiogenic factors was quantified using molecular counting analysis. MAIN RESULTS AND THE ROLE OF CHANCE: In multivariable regression, higher levels of maternal MVPA (min/day) were associated with a higher density of villi in both whole-slide images (beta 0.12; 95% CI 0.05, 0.2) and selected regions (0.17; CI 0.07, 0.26). Unexpectedly, ST was also positively associated with density of villi (0.23; CI 0.04, 0.43). MVPA and ST were not associated with vessel count/mm2 villous area, vessel area, or pro- and anti-angiogenic factor mRNA expression. All estimates and statistical significance of the sensitivity analyses excluding smokers, women who developed gestational diabetes or pre-eclampsia and/or pregnancy-induced hypertension were similar in the main analysis. LIMITATIONS, REASONS FOR CAUTION: The placenta is a complex organ undergoing dynamic changes. While various adjustments were made to account for different maternal contributing factors, in addition to the outcome measures, various other factors could impact oxygen delivery to the fetus. WIDER IMPLICATIONS OF THE FINDINGS: For the first time, we evaluated the association between placental structures quantified using an AI-based approach with objectively measured physical activity and ST at multiple time points in pregnant women with obesity. The observed adaptations contribute to the advancement of our understanding of the hemodynamics and adaptations of the placental unit in response to MVPA and ST. However, our results might not be generalizable to lean pregnant women. STUDY FUNDING/COMPETING INTEREST(S): The DALI project has received funding from the European Community's 7th Framework Program (FP7/2007-2013) under grant agreement no. 242187. The funders had no role in study design, collection of data, analyses, writing of the article, or the decision to submit it for publication. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: ISRCTN70595832.

Television Viewing from Young Adulthood to Middle Age and Premature Cardiovascular Disease Events: A Prospective Cohort Study.

BACKGROUND: Previous literature has explored the relationship between television viewing and cardiovascular disease (CVD) in adults; however, there remains a paucity of longitudinal data describing how young adult television viewing relates to premature CVD events. OBJECTIVE: To ascertain the relationship between level and annualized changes in television viewing from young adulthood to middle age and the incidence of premature CVD events before age 60. DESIGN: The Coronary Artery Risk Development in Young Adults (CARDIA) study, a prospective community-based cohort with over 30 years of follow-up (1985-present). PARTICIPANTS: Black and White men and women who were 18-30 years old at baseline (1985-1986). MAIN MEASURES: Independent variables: Individualized television viewing trajectories were developed using linear mixed models. DEPENDENT VARIABLES: Fatal and nonfatal coronary heart disease (CHD), heart failure, and stroke outcomes were analyzed separately and as a combined CVD event outcome. KEY RESULTS: Among 4318 included participants, every 1-h increase in daily hours of television viewing at age 23 was associated with higher odds of incident CHD (adjusted odds ratio [AOR] 1.26, 95% confidence interval [CI] 1.06-1.49) and incident CVD events (AOR 1.16, 95% CI 1.03-1.32). Each additional hour of daily television viewing annually was associated with higher annual odds of CHD incidence (AOR 1.55, 95% CI 1.06-2.25), stroke incidence (AOR 1.58, 95% CI 1.02-2.46), and CVD incidence (AOR 1.32, 95% CI 1.03-1.69). Race and sex modified the association between television viewing level at age 23 and CHD, heart failure, and stroke, with White men most consistently having significant associations. CONCLUSIONS: In this prospective cohort study, greater television viewing in young adulthood and annual increases in television viewing across midlife were associated with incident premature CVD events, particularly CHD. Young adulthood as well as behaviors across midlife may be important periods to promote healthy television viewing behavior patterns.

Diet Quality, Sedentary Time, and Blood Pressure in the POUCHmoms Study.

BACKGROUND: Elevated blood pressure (BP) is a major contributor to cardiovascular disease in womens; diet and sedentary time (ST) are modifiable lifestyle factors thought to influence BP. OBJECTIVES: The aim of this study was to examine 2 diet-quality measures and ST in relation to BP among parous womens. METHODS: This cross-sectional analysis uses data from 677 womens (age 25-55 y) enrolled in the Pregnancy Outcomes and Community Health (POUCH) Study and followed up in the POUCHmoms study 7-15 y after delivery (2011 and 2014). Follow-up measures included a food-frequency questionnaire (FFQ), self-report of ST (occupational and leisure), and systolic and diastolic blood pressure (SBP and DBP, respectively). The FFQ was used to calculate 2 diet-quality measures, Alternative Healthy Eating Index-2010 (AHEI) and Dietary Approaches to Stop Hypertension (DASH). Total ST h/wk was dichotomized at the median and labeled "low" or "high." In weighted unadjusted and adjusted regression models, BP was assessed in relation to diet scores (linear and threshold associations) and combinations of dichotomized diet-quality scores ("poor" = lowest quartile compared with "not poor" = upper 3 quartiles) and ST. RESULTS: Higher mean SBP and DBP occurred mainly in women with a '"poor" diet-quality score (AHEI and DASH). Among womens with a "poor"-quality diet (on the basis of the AHEI score) and "high" ST, (N = 93) adjusted mean SBP and DBP were 4.5 mmHg and 4.4 mmHg higher, respectively, than that of the counterparts who did not have a poor-quality diet and had "low" ST (N = 275). Results were similar in analyses using the DASH diet score. CONCLUSIONS: Women with poor-quality diets and more ST may need closer BP monitoring. Even modest improvements in womens' diet quality and reductions in ST might help lower their BP, but this observation needs testing in prospective studies..

Effect of depression treatment on health behaviors and cardiovascular risk factors in primary care patients with depression and elevated cardiovascular risk: data from the eIMPACT trial.

BACKGROUND: Depression is an independent risk factor for cardiovascular disease (CVD), but it is unknown if successful depression treatment reduces CVD risk. METHODS: Using eIMPACT trial data, we examined the effect of modernized collaborative care for depression on indicators of CVD risk. A total of 216 primary care patients with depression and elevated CVD risk were randomized to 12 months of the eIMPACT intervention (internet cognitive-behavioral therapy [CBT], telephonic CBT, and select antidepressant medications) or usual primary care. CVD-relevant health behaviors (self-reported CVD prevention medication adherence, sedentary behavior, and sleep quality) and traditional CVD risk factors (blood pressure and lipid fractions) were assessed over 12 months. Incident CVD events were tracked over four years using a statewide health information exchange. RESULTS: The intervention group exhibited greater improvement in depressive symptoms (p < 0.01) and sleep quality (p < 0.01) than the usual care group, but there was no intervention effect on systolic blood pressure (p = 0.36), low-density lipoprotein cholesterol (p = 0.38), high-density lipoprotein cholesterol (p = 0.79), triglycerides (p = 0.76), CVD prevention medication adherence (p = 0.64), or sedentary behavior (p = 0.57). There was an intervention effect on diastolic blood pressure that favored the usual care group (p = 0.02). The likelihood of an incident CVD event did not differ between the intervention (13/107, 12.1%) and usual care (9/109, 8.3%) groups (p = 0.39). CONCLUSIONS: Successful depression treatment alone is not sufficient to lower the heightened CVD risk of people with depression. Alternative approaches are needed. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02458690.

Cognition and Activity of Daily Living Function in people with Parkinson's disease.

The ability to perform activities of daily living (ADL) function is a multifaceted construct that reflects functionality in different daily life situations. The loss of ADL function due to cognitive impairment is the core feature for the diagnosis of Parkinson's disease dementia (PDD). In contrast to Alzheimer's disease, ADL impairment in PD can be compromised by various factors, including motor and non-motor aspects. This narrative review summarizes the current state of knowledge on the association of cognition and ADL function in people with PD and introduces the concept of "cognitive ADL" impairment for those problems in everyday life that are associated with cognitive deterioration as their primary cause. Assessment of cognitive ADL impairment is challenging because self-ratings, informant-ratings, and performance-based assessments seldomly differentiate between "cognitive" and "motor" aspects of ADL. ADL function in PD is related to multiple cognitive domains, with attention, executive function, and memory being particularly relevant. Cognitive ADL impairment is characterized by behavioral anomalies such as trial-and-error behavior or task step omissions, and is associated with lower engagement in everyday behaviors, as suggested by physical activity levels and prolonged sedentary behavior. First evidence shows that physical and multi-domain interventions may improve ADL function, in general, but the evidence is confounded by motor aspects. Large multicenter randomized controlled trials with cognitive ADL function as primary outcome are needed to investigate which pharmacological and non-pharmacological interventions can effectively prevent or delay deterioration of cognitive ADL function, and ultimately the progression and conversion to PDD.

The Annual Rhythms in Sleep, Sedentary Behavior, and Physical Activity of Australian Adults: A Prospective Cohort Study.

BACKGROUND: Sleep, sedentary behavior, and physical activity have fundamental impacts on health and well-being. Little is known about how these behaviors vary across the year. PURPOSE: To investigate how movement-related behaviors change across days of the week and seasons, and describe movement patterns across a full year and around specific temporal events. METHODS: This cohort study included 368 adults (mean age = 40.2 years [SD = 5.9]) who wore Fitbit activity trackers for 12 months to collect minute-by-minute data on sleep, sedentary behavior, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Data were analyzed descriptively, as well as through multilevel mixed-effects linear regression to explore associations with specific temporal cycles (day-of-the-week, season) and events. RESULTS: Movement patterns varied significantly by day-of-the-week and season, as well as during annual events like Christmas-New Year and daylight saving time (DST) transitions. For example, sleep was longer on weekends (+32 min/day), during autumn and winter relative to summer (+4 and +11 min/day), and over Christmas-New Year (+24 min/day). Sedentary behavior was longer on weekdays, during winter, after Christmas-New Year, and after DST ended (+45, +7, +12, and +8 min/day, respectively). LPA was shorter in autumn, winter, and during and after Christmas-New Year (-6, -15, -17, and -31 min/day, respectively). Finally, there was less MVPA on weekdays and during winter (-5 min/day and -2 min/day, respectively). CONCLUSIONS: Across the year, there were notable variations in movement behaviors. Identifying high-risk periods for unfavorable behavior changes may inform time-targeted interventions and health messaging.

Sleep, sedentary behavior, and physical activity have fundamental impacts on health and well-being, yet little is known about how these behaviors vary across the year. This study investigated how these behaviors change across days of the week, seasons, and a year, and around specific temporal events. The study included 368 middle-aged adults who wore Fitbit activity trackers for 12 months to collect minute-by-minute movement data. Statistical analyses showed movement patterns varied significantly by day-of-the-week and season, as well as during annual events like Christmas-New Year and daylight saving time transitions. For example, sleep was longer on weekends, during autumn and winter relative to summer, and over Christmas-New Year. Sedentary behavior was longer on weekdays, during winter, after Christmas-New Year, and after daylight savings time ended. Light physical activity was shorter in autumn, winter, and during and after Christmas-New Year. Finally, there was less moderate-to-vigorous physical activity on weekdays and during winter. Across the year, there were notable variations in movement patterns. Identifying high-risk periods for unfavorable behavior changes may inform time-targeted interventions and health messaging.

Momentary Associations Between Physical Activity, Affect, and Purpose in Life.

BACKGROUND: Physical activity is associated with both the hedonic (e.g., affect) and eudaimonic (e.g., purpose in life) aspects of well-being. While there is evidence linking momentary physical activity and affect in daily life, the examination of momentary purpose remains largely unexplored. PURPOSE: This study investigates the bidirectional associations between physical activity, positive and negative affect, and momentary purpose using Ecological Momentary Assessment (EMA) and accelerometer data. METHODS: Middle-aged participants (40-70 years old, n = 291) wore accelerometers and completed three daily EMA surveys on momentary experiences for 8 consecutive days. Physical activity (active time and counts) from 20- to 60-min periods before and after EMA surveys were used in the analyses. Multilevel models were adjusted for temporal and contextual factors, age, sex, education, work status, and race/ethnicity. RESULTS: When participants were more physically active than usual, they reported feeling more purpose-driven and positive affect. Similarly, when participants reported feeling more purpose-driven or experiencing positive affect, they engaged in more physical activity in the subsequent time period. These associations were similar for physical activity from 20- to 60-min periods before and after the EMA survey. Physical activity and negative affect were not related in either direction. CONCLUSIONS: In middle-aged adults' daily lives, physical activity has bidirectional relations with purpose and positive affect. This study highlights the dynamic associations between physical activity and the positive aspects of both hedonic and eudaimonic well-being. Future interventions or public health programs should integrate physical activity and mental well-being to maximize mutual benefits.

This study examined how physical activity relates to feelings of purpose and positive and negative affect in daily life among middle-aged adults (aged 40­70). Participants wore activity trackers and completed surveys on their smartphones about their feelings three times a day for 8 days. The study found that when participants were more physically active than usual, they experienced higher levels of purpose and more positive emotions. Conversely, feeling more purposeful or positive also led to more physical activity later on. The results suggest that physical activity and positive well-being are interconnected and reinforce each other in daily life.

Accelerometer-measured physical activity, sedentary behavior, and risk of incident pelvic organ prolapse: a prospective cohort study in the UK Biobank.

BACKGROUND: Previous studies on physical activity (PA) and pelvic organ prolapse (POP) were largely limited to self-reported PA in athletes, soldiers, and women in postpartum. We aimed to investigate the association of accelerometer-measured PA and sedentary behavior with the risk of POP in middle-aged and elderly women. METHODS: In this prospective cohort derived from the UK Biobank, the intensity and duration of PA and sedentary behavior were measured with wrist-worn accelerometers over a 7-day period in 2013-2015 for 47,674 participants (aged 42.8-77.9 years) without pre-existing POP. Participants were followed up until the end of 2022, during which incident POP was ascertained mainly by the electronic health records. Multivariable-adjusted Cox proportional hazards models and restricted cubic splines were used to assess the associations of interest. Isotemporal substitution models were applied to test the effects of substituting a type of activity with equivalent duration of others. RESULTS: During a median follow-up of 8.0 years, 779 cases of POP were recorded. The duration of light-intensity PA (LPA) was positively whereas sedentary time was negatively associated with the risk of POP. Every additional 1 h/day of LPA elevated the risk of POP by 18% (95% confidence interval [CI], 10%-26%). In contrast, the risk decreased by 5% (95% CI, 0-8%) per 1 h/day increment in sedentary behavior. No associations were found between moderate-intensity PA (MPA) or vigorous-intensity PA (VPA) and POP, except that women who had a history of hysterectomy were more likely to develop POP when performing more VPA (53% higher risk for every additional 15 min/day). Substituting 1 h/day of LPA with equivalent sedentary time was associated with a 18% (95% CI, 11%-24%) lower risk of POP. The risk can also be reduced by 17% (95% CI, 7%-25%) through substituting 30 min/day of LPA with MPA. CONCLUSIONS: More time spent in LPA or less sedentary time was linked to an elevated risk of POP in middle-aged and elderly women, while MPA or VPA was not. Substituting LPA with equivalent duration of sedentary behavior or MPA may lower the risk of POP.

Cost-effectiveness of reducing children's sedentary time and increasing physical activity at school: the Transform-Us! intervention.

BACKGROUND: Improving physical activity and reducing sedentary behavior represent important areas for intervention in childhood in order to reduce the burden of chronic disease related to obesity and physical inactivity in later life. This paper aims to determine the cost-effectiveness of a multi-arm primary school-based intervention to increase physical activity and/or reduce sedentary time in 8-9 year old children (Transform-Us!). METHODS: Modelled cost-utility analysis, using costs and effects from a cluster randomized controlled trial of a 30-month intervention that used pedagogical and environmental strategies to reduce and break up sedentary behaviour (SB-I), promote physical activity (PA-I), or a combined approach (PA + SB-I), compared to current practice. A validated multiple-cohort lifetable model (ACE-Obesity Policy model) estimated the obesity and physical activity-related health outcomes (measured as change in body mass index and change in metabolic equivalent task minutes respectively) and healthcare cost-savings over the cohort's lifetime from the public-payer perspective, assuming the intervention was delivered to all 8-9 year old children attending Australian Government primary schools. Sensitivity analyses tested the impact on cost-effectiveness of varying key input parameters, including maintenance of intervention effect assumptions. RESULTS: Cost-effectiveness results demonstrated that, when compared to control schools, the PA-I and SB-I intervention arms were "dominant", meaning that they resulted in net health benefits and healthcare cost-savings if the intervention effects were maintained. When the costs and effects of these intervention arms were extrapolated to the Australian population, results suggested significant potential as obesity prevention measures (PA-I: 60,780 HALYs saved (95% UI 15,007-109,413), healthcare cost-savings AUD641M (95% UI AUD165M-$1.1B); SB-I: 61,126 HALYs saved (95% UI 11,770 - 111,249), healthcare cost-savings AUD654M (95% UI AUD126M-1.2B)). The PA-I and SB-I interventions remained cost-effective in sensitivity analysis, assuming the full decay of intervention effect after 10 years. CONCLUSIONS: The PA-I and SB-I Transform-Us! intervention arms represent good value for money and could lead to health benefits and healthcare cost-savings arising from the prevention of chronic disease in later life if intervention effects are sustained. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number (ISRCTN83725066). Australia and New Zealand Clinical Trials Registry Number (ACTRN12609000715279).

Using functional principal component analysis (FPCA) to quantify sitting patterns derived from wearable sensors.

BACKGROUND: Sedentary behavior (SB) is a recognized risk factor for many chronic diseases. ActiGraph and activPAL are two commonly used wearable accelerometers in SB research. The former measures body movement and the latter measures body posture. The goal of the current study is to quantify the pattern and variation of movement (by ActiGraph activity counts) during activPAL-identified sitting events, and examine associations between patterns and health-related outcomes, such as systolic and diastolic blood pressure (SBP and DBP). METHODS: The current study included 314 overweight postmenopausal women, who were instructed to wear an activPAL (at thigh) and ActiGraph (at waist) simultaneously for 24 hours a day for a week under free-living conditions. ActiGraph and activPAL data were processed to obtain minute-level time-series outputs. Multilevel functional principal component analysis (MFPCA) was applied to minute-level ActiGraph activity counts within activPAL-identified sitting bouts to investigate variation in movement while sitting across subjects and days. The multilevel approach accounted for the nesting of days within subjects. RESULTS: At least 90% of the overall variation of activity counts was explained by two subject-level principal components (PC) and six day-level PCs, hence dramatically reducing the dimensions from the original minute-level scale. The first subject-level PC captured patterns of fluctuation in movement during sitting, whereas the second subject-level PC delineated variation in movement during different lengths of sitting bouts: shorter (< 30 minutes), medium (30 -39 minutes) or longer (> 39 minute). The first subject-level PC scores showed positive association with DBP (standardized ß ^ : 2.041, standard error: 0.607, adjusted p = 0.007), which implied that lower activity counts (during sitting) were associated with higher DBP. CONCLUSION: In this work we implemented MFPCA to identify variation in movement patterns during sitting bouts, and showed that these patterns were associated with cardiovascular health. Unlike existing methods, MFPCA does not require pre-specified cut-points to define activity intensity, and thus offers a novel powerful statistical tool to elucidate variation in SB patterns and health. TRIAL REGISTRATION: ClinicalTrials.gov NCT03473145; Registered 22 March 2018; https://clinicaltrials.gov/ct2/show/NCT03473145 ; International Registered Report Identifier (IRRID): DERR1-10.2196/28684.

Development and content validity of an application to assess 24-hour movement behaviors in 0-4-year-old children involving end-users and key stakeholders: the My Little Moves app.

BACKGROUND: Recently, research focus has shifted to the combination of all 24-h movement behaviors (physical activity, sedentary behavior and sleep) instead of each behavior separately. Yet, no reliable and valid proxy-report tools exist to assess all these behaviors in 0-4-year-old children. By involving end-users (parents) and key stakeholders (researchers, professionals working with young children), this mixed-methods study aimed to 1) develop a mobile application (app)-based proxy-report tool to assess 24-h movement behaviors in 0-4-year-olds, and 2) examine its content validity. METHODS: First, we used concept mapping to identify activities 0-4-year-olds engage in. Parents (n = 58) and professionals working with young children (n = 21) generated a list of activities, sorted related activities, and rated the frequency children perform these activities. Second, using multidimensional scaling and cluster analysis, we created activity categories based on the sorted activities of the participants. Third, we developed the My Little Moves app in collaboration with a software developer. Finally, we examined the content validity of the app with parents (n = 14) and researchers (n = 6) using focus groups and individual interviews. RESULTS: The app has a time-use format in which parents proxy-report the activities of their child, using eight activity categories: personal care, eating/drinking, active transport, passive transport, playing, screen use, sitting/lying calmly, and sleeping. Categories are clarified by providing examples of children's activities. Additionally, 1-4 follow-up questions collect information on intensity (e.g., active or calm), posture, and/or context (e.g., location) of the activity. Parents and researchers considered filling in the app as feasible, taking 10-30 min per day. The activity categories were considered comprehensive, but alternative examples for several activity categories were suggested to increase the comprehensibility and relevance. Some follow-up questions were considered less relevant. These suggestions were adopted in the second version of the My Little Moves app. CONCLUSIONS: Involving end-users and key stakeholders in the development of the My Little Moves app resulted in a tailored tool to assess 24-h movement behaviors in 0-4-year-olds with adequate content validity. Future studies are needed to evaluate other measurement properties of the app.

Losing sleep influences dietary intake in children: a longitudinal compositional analysis of a randomised crossover trial.

BACKGROUND: Although inadequate sleep increases the risk of obesity in children, the mechanisms remain unclear. The aims of this study were to assess how sleep loss influenced dietary intake in children while accounting for corresponding changes in sedentary time and physical activity; and to investigate how changes in time use related to dietary intake. METHODS: A randomized crossover trial in 105 healthy children (8-12 years) with normal sleep (~ 8-11 h/night) compared sleep extension (asked to turn lights off one hour earlier than usual for one week) and sleep restriction (turn lights off one hour later) conditions, separated by a washout week. 24-h time-use behaviors (sleep, wake after sleep onset, physical activity, sedentary time) were assessed using waist-worn actigraphy and dietary intake using two multiple-pass diet recalls during each intervention week. Longitudinal compositional analysis was undertaken with mixed effects regression models using isometric log ratios of time use variables as exposures and dietary variables as outcomes, and participant as a random effect. RESULTS: Eighty three children (10.2 years, 53% female, 62% healthy weight) had 47.9 (SD 30.1) minutes less sleep during the restriction week but were also awake for 8.5 (21.4) minutes less at night. They spent this extra time awake in the day being more sedentary (+ 31 min) and more active (+ 21 min light physical activity, + 4 min MVPA). After adjusting for all changes in 24-h time use, losing 48 min of sleep was associated with consuming significantly more energy (262 kJ, 95% CI:55,470), all of which was from non-core foods (314 kJ; 43, 638). Increases in sedentary time were related to increased energy intake from non-core foods (177 kJ; 25, 329) whereas increases in MVPA were associated with higher intake from core foods (72 kJ; 7,136). Changes in diet were greater in female participants. CONCLUSION: Loss of sleep was associated with increased energy intake, especially of non-core foods, independent of changes in sedentary time and physical activity. Interventions focusing on improving sleep may be beneficial for improving dietary intake and weight status in children. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ANZCTR ACTRN12618001671257, Registered 10th Oct 2018, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=367587&isReview=true.

Joint associations of sedentary behavior and domain-specific physical activity on C-reactive protein in Korea.

Sedentary behavior (SB) and physical activity (PA) exert opposing effects on inflammatory markers. This study examined the associations of a more subdivided combination of PA and SB with high-sensitivity C-reactive protein (hs-CRP). Using the 2014-2019 Korean National Health and Nutrition Examination Survey, this cross-sectional study analyzed 20,541 adults. The independent variables were SB, defined as ≥10 h of sitting per day, and three domains of PA: occupational PA (OPA) during work, leisure-time PA (LPA) during leisure time, and transportation PA (TPA) or active commuting. The dependent variable was hs-CRP ≥ 1.0 mg/L. Besides exploring the individual association of SB and each PA with hs-CRP, the combined association of SB and each PA with hs-CRP was also examined using multiple logistic regression. The analyses indicated that concurrent exposure to SB and OPA (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.02-1.80) significantly raised the likelihood of increased hs-CRP, while SB without LPA (OR 1.26, 95% CI 1.11-1.41) or TPA (OR 1.19, 95% CI 1.08-1.31) significantly increased risk of higher hs-CRP, compared to their respective reference. The absence of non-occupational PA such as LPA or TPA combined with SB was associated with the increased hs-CRP risk, whereas OPA increased the risk when present concurrently with SB. Reducing SB and OPA while increasing LPA and TPA, is necessary to reduce inflammatory conditions.