Patterns Of Sedentary Time Research Articles

Patterns of sedentary behaviour in adults with acute insomnia derived from actigraphy data.

Sleep disorders, such as insomnia, have been associated with extended periods of inactive, sedentary behaviour. Many factors contribute to insomnia, including stress, irregular sleep patterns, mental health issues, inadequate sleeping schedules, diseases, neurological disorders and prescription medications. Identification of the patterns of sedentary time and its duration in adults with acute insomnia and healthy controls to determine the statistically significant sedentary bouts; comparison of the sedentary behaviour patterns in acute insomnia adults with healthy controls. We investigate the daytime actigraphy data and identify temporal patterns of inactivity among adults with acute insomnia and healthy adults. Seven days of actigraphy data were utilised to calculate sedentary time and bouts of variable duration based on a threshold of activity counts (<100 counts per minute). Statistical analysis was applied to investigate sedentary bouts and total sedentary time during weekdays and weekend. A logistic regression model has been used to determine the significance of sedentary bouts. We found that individuals with acute insomnia accumulate a significant amount of their sedentary time in medium (6-30 minutes and 31-60 minutes) and longer (more than 60 minutes) duration bouts in comparison to healthy adults. Furthermore, a low p value for total sedentary time (2.54 ⋅ 10-4) association with acute insomnia supports the finding that acute insomnia individuals are significantly more engaged in sedentary activities compared to healthy controls. Also, as shown by the weekend vs weekday analysis, the physical and sedentary activity patterns of acute insomnia adults demonstrate higher variability during the weekdays in comparison to the weekend. The results of the present study demonstrate that adults with acute insomnia spend more time in low-intensity daily physical activities compared to healthy adults.

Daily patterns of physical activity, sedentary behavior, and prevalent and incident depression-The Maastricht Study.

This study aims to compare the accelerometer-measured daily patterns of PA and sedentary behavior among participants with and without prevalent/incident depressive symptoms. We used data from 5582 individuals in The Maastricht Study (59.9 ± 8.6 years, 50.3% women). Daily patterns of sedentary time, light-intensity physical activity (LiPA), moderate-to-vigorous physical activity (MVPA), and sit-to-stand transitions were objectively measured at baseline with the activPAL3 activity monitor. Depressive symptoms were assessed using the 9-item Patient Health Questionnaire, both at baseline and annually (median follow-up: 5.1 years). General linear models were used to compare patterns of physical activity and sedentary behavior between those with and without prevalent/incident depressive symptoms. Participants with prevalent depressive symptoms had significantly more sedentary time (18.6min/day) and lower LiPA (26.8min/day) and MVPA (4.8min/day) than participants without depressive symptoms. Considering the daily patterns, participants with prevalent depressive symptoms had significantly more sedentary time early in the afternoon (12:00-18:00), early evening (18:00-21:00), and during the night (00:00-03:00), less time in LiPA in all periods between 09:00-21.00 and less MVPA in the morning (09:00:12:00), early afternoon (12:00-15:00), and evening (18:00-21:00), than those without. Similar differences in activity and sedentary behavior patterns between those and without incident depressive symptoms were observed albeit the differences were smaller. Overall, we did not find specific time slots particularly associated with both prevalent and incident depressive symptoms. These findings may indicate that less sedentary time and more intense PA can be important targets for the prevention of depression irrespective of the timing of the day.

The role of socio-demographic factors and physical functioning in the intra- and interpersonal variability of older adults’ sedentary time: an observational two-country study

BackgroundInsight into the variability of older adults’ sedentary time is needed to inform future interventions. The aim of this study was to examine the intra- and interpersonal variability in sedentary time, and the moderating role of socio-demographics, physical functioning and geographical location in this variability.MethodsCross-sectional data from 818 community-dwelling older adults (mean age: 74.8 years; 61.1%women) of the Active Lifestyle and the Environment in Chinese Seniors and Belgian Environmental Physical Activity Study in Seniors were used. An interview questionnaire was administered to collect socio-demographic information. The Short Physical Performance Battery was performed to evaluate physical functioning, and Actigraph GT3X( +) accelerometers were used to estimate sedentary time. Linear mixed models with random intercepts at the neighborhood, person and day levels examined the variability in sedentary time, and the moderating role of socio-demographics, physical functioning and geographical location within this variability.ResultsMost of the variance in accelerometry-assessed sedentary time was due to intrapersonal variability across periods of the day (72.4%) followed by interpersonal variability within neighborhoods (25.6%). Those who were older, men, lived in Hong Kong, and experienced a lower level of physical functioning were more sedentary than their counterparts. Sedentary time increased throughout the day, with highest levels of sedentary time observed between 6:00 and 9:00 pm. The patterns of sedentary time across times of the day differed by gender, educational attainment, age, physical functioning and/or geographical location. No significant differences were detected between week and weekend day sedentary time.ConclusionsThe oldest old, men, and those with functional limitations are important target groups for sedentary behavior interventions. As sedentary time was the highest in the evening future sedentary behavior intervention should pay particular attention to the evening hours. The variations in diurnal patterns of sedentary time between population subgroups suggest that personalized just-in-time adaptive interventions might be a promising strategy to reduce older adults’ sedentary time.

People with Stroke Are Most Sedentary in the Afternoon and Evening

Questions: What are the daily temporal patterns of movement behaviours (sedentary time, light-intensity physical activity, and moderate-vigorous physical activity) in people with stroke? Do daily temporal patterns of sedentary time differ (a) between subgroups of people with different movement behaviour classifications and (b) over time during the first year after stroke? Design: This study represents secondary exploratory analyses from an observational, longitudinal cohort study (n = 197). Participants: This study included people with first-ever stroke recruited from 4 hospitals in the Netherlands. Outcome Measures: Movement behaviour was objectively measured using the Activ8 activity monitor within 3 weeks after hospital discharge and again at 6 and 12 months later. Results: Participants spent the least time sedentary in the morning with proportionally more sedentary time as the day progressed with maximal sedentary time seen in the evening hours. This pattern did not substantially change over time. Sedentary prolongers spent significantly more absolute time sedentary for each hour of the day, but the daily temporal pattern of sedentary time did not differ between this group and either “sedentary movers” or “sedentary exercisers.” Conclusion: People living at home after stroke are highly sedentary, particularly in the afternoons and evenings, and this pattern does not change during the first year after stroke. Clinicians should encourage people with stroke to find meaningful tasks to do during the day to reduce their sitting time. Researchers developing interventions to encourage people to sit less should include particular focus on the afternoon and evening time periods.

Does physical activity moderate the association between device-measured sedentary time patterns and depressive symptoms in adults?

To investigate the association between sedentary time (ST) patterns and depressive symptoms, and whether moderate-to-vigorous physical activity (MVPA) can moderate this association. This cross-sectional study included a representative sample of 243 adults (mean age 41.8±16.7 years, 56.4% women) from a city in Southeast Brazil. Depressive symptoms were estimated through the Hospital Anxiety and Depression Scale (HADS). ST patterns (i.e., number of breaks, mean length of sedentary bouts, and number of long sedentary bouts), total ST, and MVPA were assessed using accelerometers. Poisson regression models revealed associations of total ST (ß = 0.063; 95%CI 0.011 to 0.116) and number of long bouts (0.108; 0.047 to 0.171) with depressive symptoms among men. MVPA moderated the associations of breaks and longer bouts of ST with depressive symptoms, with an increase of one break/hour, the increase of one long bout, and a decrease of 1 minute in mean bout length being associated with a reduction of 0.211 and increases of 0.081 and 0.166, respectively, in the number of depressive symptoms among men with physical inactivity (breaks = -0.211; -0.360 to -0.063; mean bout length = 0.081; 0.003 to 0.158; number of long bouts = 0.166; 0.090 to 0.242). Interventions that encourage breaking up ST should be helpful to reduce depressive symptoms among people with physical inactivity.

Accumulation patterns of sedentary time and breaks and their association with cardiometabolic health markers in adults.

Breaking up sedentary time with physical activity (PA) could modify the detrimental cardiometabolic health effects of sedentary time. Our aim was to identify profiles according to distinct accumulation patterns of sedentary time and breaks in adults, and to investigate how these profiles are associated with cardiometabolic outcomes. Participants (n=4439) of the Northern Finland Birth Cohort 1966 at age 46years wore a hip-worn accelerometer for 7 consecutive days during waking hours. Uninterrupted ≥1-min sedentary bouts were identified, and non-sedentary bouts in between two consecutive sedentary bouts were considered as sedentary breaks. K-means clustering was performed with 65 variables characterizing how sedentary time was accumulated and interrupted. Linear regression was used to determine the association of accumulation patterns with cardiometabolic health markers. Four distinct groups were formed as follows: "Couch potatoes" (n=1222), "Prolonged sitters" (n=1179), "Shortened sitters" (n=1529), and "Breakers" (n=509). Couch potatoes had the highest level of sedentariness and the shortest sedentary breaks. Prolonged sitters, accumulating sedentary time in bouts of ≥15-30min, had no differences in cardiometabolic outcomes compared with Couch potatoes. Shortened sitters accumulated sedentary time in bouts lasting <15min and performed more light-intensity PA in their sedentary breaks, and Breakers performed more light-intensity and moderate-to-vigorous PA. These latter two profiles had lower levels of adiposity, blood lipids, and insulin sensitivity, compared with Couch potatoes (1.1-25.0% lower values depending on the cardiometabolic health outcome, group, and adjustments for potential confounders). Avoiding uninterrupted sedentary time with any active behavior from light-intensity upwards could be beneficial for cardiometabolic health in adults.

An Exploration of Sedentary Behavior Patterns in Community-Dwelling People With Stroke: A Cluster-Based Analysis.

Long periods of daily sedentary time, particularly accumulated in long uninterrupted bouts, are a risk factor for cardiovascular disease. People with stroke are at high risk of recurrent events and prolonged sedentary time may increase this risk. We aimed to explore how people with stroke distribute their periods of sedentary behavior, which factors influence this distribution, and whether sedentary behavior clusters can be distinguished? This was a secondary analysis of original accelerometry data from adults with stroke living in the community. We conducted data-driven clustering analyses to identify unique accumulation patterns of sedentary time across participants, followed by multinomial logistical regression to determine the association between the clusters, and the total amount of sedentary time, age, gender, body mass index (BMI), walking speed, and wake time. Participants in the highest quartile of total sedentary time accumulated a significantly higher proportion of their sedentary time in prolonged bouts (P < 0.001). Six unique accumulation patterns were identified, all of which were characterized by high sedentary time. Total sedentary time, age, gender, BMI, and walking speed were significantly associated with the probability of a person being in a specific accumulation pattern cluster, P < 0.001 - P = 0.002. Although unique accumulation patterns were identified, there is not just one accumulation pattern for high sedentary time. This suggests that interventions to reduce sedentary time must be individually tailored.Video Abstract available for more insight from the authors (see the Video Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A343).

Patterns of Sedentary Time in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Youth.

Total sedentary time and prolonged sedentary patterns can negatively impact health. This study investigated rates of various sedentary pattern variables in Hispanic/Latino youth. Participants were 956 youths (50.9% female) in the Hispanic Community Health Study/Study of Latinos Youth, a population-based cohort study of Hispanic/Latino 8- to 16-year-olds from 4 geographic regions in the United States (2012-2014). Total sedentary time and 10 sedentary pattern variables were measured through 1 week of accelerometer wear. Differences were examined by sociodemographic characteristics, geographic location, weekdays versus weekends, and season. On average, youth were sedentary during 67.3% of their accelerometer wear time, spent 24.2% engaged in 10- to 29-minute sedentary bouts, and 7.2% in ≥60-minute bouts. 8- to 12-year-olds had more favorable sedentary patterns (less time in extended bouts and more breaks) than 13- to 16-year-olds across all sedentary variables. Sedentary patterns also differed by Hispanic/Latino background, with few differences across sex, household income, season, and place of birth, and none between weekdays versus weekends. Variables representing prolonged sedentary time were high among Hispanic/Latino youth. Adolescents in this group appear to be at especially high risk for unhealthy sedentary patterns. Population-based efforts are needed to prevent youth from engaging in increasingly prolonged sedentary patterns.

Differences in adolescent activity and dietary behaviors across home, school, and other locations warrant location-specific intervention approaches

BackgroundInvestigation of physical activity and dietary behaviors across locations can inform “setting-specific” health behavior interventions and improve understanding of contextual vulnerabilities to poor health. This study examined how physical activity, sedentary time, and dietary behaviors differed across home, school, and other locations in young adolescents.MethodsParticipants were adolescents aged 12–16 years from the Baltimore-Washington, DC and the Seattle areas from a larger cross-sectional study. Participants (n = 472) wore an accelerometer and Global Positioning Systems (GPS) tracker (Mean days = 5.12, SD = 1.62) to collect location-based physical activity and sedentary data. Participants (n = 789) completed 24-h dietary recalls to assess dietary behaviors and eating locations. Spatial analyses were performed to classify daily physical activity, sedentary time patterns, and dietary behaviors by location, categorized as home, school, and “other” locations.ResultsAdolescents were least physically active at home (2.5 min/hour of wear time) and school (2.9 min/hour of wear time) compared to “other” locations (5.9 min/hour of wear time). Participants spent a slightly greater proportion of wear time in sedentary time when at school (41 min/hour of wear time) than at home (39 min/hour of wear time), and time in bouts lasting ≥30 min (10 min/hour of wear time) and mean sedentary bout duration (5 min) were highest at school. About 61% of daily energy intake occurred at home, 25% at school, and 14% at “other” locations. Proportionately to energy intake, daily added sugar intake (5 g/100 kcal), fruits and vegetables (0.16 servings/100 kcal), high calorie beverages (0.09 beverages/100 kcal), whole grains (0.04 servings/100 kcal), grams of fiber (0.65 g/100 kcal), and calories of fat (33 kcal/100 kcal) and saturated fat (12 kcal/100 kcal) consumed were nutritionally least favorable at “other” locations. Daily sweet and savory snacks consumed was highest at school (0.14 snacks/100 kcal).ConclusionsAdolescents’ health behaviors differed based on the location/environment they were in. Although dietary behaviors were generally more favorable in the home and school locations, physical activity was generally low and sedentary time was higher in these locations. Health behavior interventions that address the multiple locations in which adolescents spend time and use location-specific behavior change strategies should be explored to optimize health behaviors in each location.

Longitudinal associations of sedentary time and physical activity duration and patterns with cognitive development in early childhood

ImportanceSedentary behaviour and physical activity are important to consider for optimal cognitive development. Few studies have examined patterns (i.e., bouts/breaks) of these behaviours in early childhood and longitudinal associations with cognitive outcomes. ObjectivesExamine: 1) changes in total duration and patterns of sedentary time and physical activity across three time-points, separated by approximately six-months; and 2) longitudinal associations of sedentary time and physical activity (i.e., duration and patterns) with cognitive development in early childhood. MethodParticipants included 100 children aged 2.5–5.0 years at time-point 1. Participants wore ActiGraph accelerometers and completed measures of cognition: inhibitory control (Fish-Shark Go/No-Go task), working memory (Nebraska Barnyard task), and general cognitive ability (Woodcock-Johnson III test battery) at two/three time-points. Multilevel growth modelling was used to examine total duration and patterns (i.e., bouts and breaks) of sedentary behaviour and physical activity over time and longitudinal associations with cognitive outcomes. ResultsTotal sedentary time decreased (β [95% CI] = −9.24 [-15.76, −2.72]; β represents estimated change per year), whereas time spent in moderate-to-vigorous-intensity physical activity (MVPA; 5.65 [1.89, 9.41]) increased over time. A significant decrease in time spent in ≥10-min sedentary bouts (−9.76 [-13.56, −5.96]), and significant increases in sedentary breaks (13.41 [7.18, 19.63]) and time spent in 1-3-min (2.56 [0.96, 4.15]) and 3-5-min bouts of MVPA (0.86 [0.33, 1.38]) were also found. There was minimal evidence of longitudinal associations between the accelerometry variables and cognitive outcomes. ConclusionsThe observed changes in sedentary time and MVPA over time are promising for child health. Nevertheless, no meaningful associations with cognitive outcomes were found. Future studies with larger sample sizes should investigate whether specific types of activities that children engage in are associated with cognitive development overtime. Overall, this body of evidence could help inform future updates of guidelines concerning patterns of activity and health in the early years.

Diurnal patterns of sedentary time in rheumatoid arthritis: associations with cardiovascular disease risk

ObjectivesResearch demonstrates that sedentary behaviour may contribute towards cardiovascular disease (CVD) risk in rheumatoid arthritis (RA). This study explored diurnal patterns of sedentary time and physical activity (PA) in RA...

Diurnal patterns of objectively measured sedentary time and interruptions to sedentary time are associated with glycaemic indices in type 2 diabetes

ObjectivesTo investigate diurnal patterns of sedentary time and interruptions to sedentary time and their associations with achievement of pre-meal glucose, post-meal glucose, bedtime glucose and the dawn phenomenon targets and with duration of hypoglycaemia, euglycaemia, hyperglycaemia and above target range. DesignIntensive longitudinal study. MethodsIn 37 adults with type 2 diabetes, the FreeStyle Libre and activPAL3 were used to monitor glucose and sedentary time and interruptions to sedentary time in the morning (07:00–12:00), afternoon (12:00–17:00) and evening (17:00–23:00) for 14 days. Diurnal patterns of sedentary behaviour and associations with glycaemic indices were assessed using repeated measures ANOVA and linear regressions. ResultsSedentary time was significantly higher in the evening (43.47±7.37min/h) than the morning (33.34±8.44min/h) and afternoon (37.26±8.28min/h). Interruptions to sedentary time were significantly lower in the evening (2.64±0.74n/h) than the morning (3.69±1.08n/h) and afternoon (3.06±0.87n/h). Sedentary time in the morning and afternoon was associated with lower achievement of the dawn phenomenon target. Sedentary time in the evening was associated with lower achievement of post-lunch glucose target. Interruptions to sedentary time in the morning and afternoon were associated with higher achievement of pre-dinner glucose target. Interruptions to sedentary time in the evening showed beneficial associations with achievement of post-dinner glucose and bedtime glucose targets and euglycaemia. ConclusionsProlonged sedentary behaviour is high in the evening. Interruptions to sedentary time, particularly in the evening, have beneficial associations with glycaemic indices. Interventions targeting interruptions to sedentary time in the evening may be more clinically relevant.

Patterns of Sedentary Time and Quality of Life in Women With Fibromyalgia: Cross-Sectional Study From the al-Ándalus Project.

BackgroundSedentary time (ST) has been associated with detrimental health outcomes in fibromyalgia. Previous evidence in the general population has shown that not only is the total amount of ST harmful but the pattern of accumulation of sedentary behaviors is also relevant to health, with prolonged unbroken periods (ie, bouts) being particularly harmful.ObjectiveTo examine the association of the patterns of ST with health-related quality of life (HRQoL) in women with fibromyalgia and to test whether these associations are independent of moderate-to-vigorous physical activity (MVPA).MethodsA total of 407 women (mean 51.4 years of age [SD 7.6]) with fibromyalgia participated. ST and MVPA were measured with triaxial accelerometry. The percentage of ST accumulated in bouts and the frequency of sedentary bouts of different lengths (≥10 min, ≥20 min, ≥30 min, and ≥60 min) were obtained. Four groups combining total ST and sedentary bout duration (≥30 min) were created. We assessed HRQoL using the 36-item Short-Form Health Survey (SF-36).ResultsA greater percentage of ST spent in all bout lengths was associated with worsened physical function, bodily pain, vitality, social function, and physical component summary (PCS) (all P<.05). In addition, a higher percentage of ST in bouts of 60 minutes or more was related to worsened physical role (P=.04). A higher frequency of bouts was negatively associated with physical function, social function, the PCS (≥30 min and ≥60 min), physical role (≥60 min), bodily pain (≥60 min), and vitality (≥20 min, ≥30 min, and ≥60 min) (all P<.05). Overall, for different domains of HRQoL, these associations were independent of MVPA for higher bout lengths. Patients with high total ST and high sedentary bout duration had significantly worsened physical function (mean difference 8.73 units, 95% CI 2.31-15.15; independent of MVPA), social function (mean difference 10.51 units, 95% CI 2.59-18.44; not independent of MVPA), and PCS (mean difference 2.71 units, 95% CI 0.36-5.06; not independent of MVPA) than those with low ST and low sedentary bout duration.ConclusionsGreater ST in prolonged periods of any length and a higher frequency of ST bouts, especially in longer bout durations, are associated with worsened HRQoL in women with fibromyalgia. These associations were generally independent of MVPA.

Patterns of Sedentary Behavior in the First Month After Acute Coronary Syndrome.

BackgroundSedentary behavior is a key contributor to cardiovascular disease. Few data exist on the sedentary behavior patterns of patients with acute coronary syndrome.Methods and ResultsWe characterized patterns of sedentary time and their correlates in 149 patients with acute coronary syndrome over the first month postdischarge, a critical period when lifestyle behaviors are formed. Sedentary time was measured by accelerometry for 28 days postdischarge. Group‐based modeling at the day level was used to characterize sedentary patterns. Participants spent a mean of 9.7±2.0 hours per day sedentary during the 28 days postdischarge, with significant decreases in sedentary time observed in each consecutive week (P<0.01 for all). Three distinct sedentary patterns were identified: high (20.6% of participants), moderate (47.9%), and low (31.5%). The high and moderate sedentary groups spent a mean of 12.6±0.8 and 10.0±0.7 hours per day sedentary, respectively, and had only minimal decreases in their sedentary time (<3 minutes per day) over the 28 days. The low sedentary group spent a mean of 7.3±0.8 hours per day sedentary, with a rapid decrease in sedentary time (14 minutes per day) observed during the first week postdischarge followed by a relatively smaller decrease (≈5 minutes per day) that persisted until day 21 postdischarge. Non‐Hispanic ethnicity, left ventricular ejection fraction <40%, lower physical health–related quality of life, and not having a partner were associated with an increased likelihood of being in the high sedentary group.ConclusionsSurvivors of acute coronary syndrome accrued high volumes of sedentary time during the first month postdischarge, with most showing little change over time. Interventions targeting reductions in sedentary time among survivors of acute coronary syndrome may be warranted, particularly for those with poor physical health and greater disease severity.

The association between patterns of physical activity and sedentary time with frailty in relation to cardiovascular disease.

ObjectiveThe associations of moderate‐vigorous physical activity (MVPA) bouts and patterns of sedentary time (ST) with frailty according to cardiovascular disease (CVD) status are unknown.MethodsAccelerometry in adults ≥50 years old from the 2003‐2004 and 2005‐2006 National Health and Nutrition Examination Survey were used. Bouted and sporadic MVPA in ≥10‐minute or <1‐minute bouts were assessed based on meeting a percentage of physical activity guidelines of 150 minutes/wk, respectively. ST patterns included: prolonged ST lasting ≥30 minutes, and the frequency, intensity, and duration of breaks from ST. A 46‐item frailty index defined frailty. Multivariable linear regression was used.ResultsThere were 827 and 1490 CVD‐free and CVD participants, respectively. Meeting a higher percentage of the physical activity guidelines through bouted MVPA was associated with lower frailty in CVD‐only participants (P < 0.05 for CVD interaction). Sporadic MVPA was associated with lower frailty levels in both groups. Prolonged ST was associated with worse frailty in CVD (P > 0.05 for CVD interaction). Frequency of ST breaks was not associated with frailty. Average ST break intensity was protective in both groups. The duration of breaks in ST was associated with lower frailty in CVD participants only (P > 0.05 for CVD interaction).ConclusionInsufficient MVPA and prolonged ST are detrimental despite CVD status.

Sedentary behavior and cardiovascular disease in older women: The Objective Physical Activity and Cardiovascular Health (OPACH) Study.

Evidence that higher sedentary time is associated with higher risk for cardiovascular disease (CVD) is based mainly on self-reported measures. Few studies have examined whether patterns of sedentary time are associated with higher risk for CVD. Women from the Objective Physical Activity and Cardiovascular Health (OPACH) Study (n=5638, aged 63-97, mean age=79±7) with no history of myocardial infarction (MI) or stroke wore accelerometers for 4-to-7 days and were followed for up to 4.9 years for CVD events. Average daily sedentary time and mean sedentary bout duration were the exposures of interest. Cox regression models estimated hazard ratios (HR) and 95% confidence intervals (CI) for CVD using models adjusted for covariates and subsequently adjusted for potential mediators (body mass index (BMI), diabetes, hypertension, and CVD-risk biomarkers [fasting glucose, high-density lipoprotein, triglycerides, and systolic blood pressure]). Restricted cubic spline regression characterized dose-response relationships. There were 545 CVD events during 19,350 person-years. Adjusting for covariates, women in the highest (≥ ~11 hr/day) vs. the lowest (≤ ~9 hr/day) quartile of sedentary time had higher risk for CVD (HR=1.62; CI=1.21-2.17; p-trend <0.001). Further adjustment for potential mediators attenuated but did not eliminate significance of these associations (p-trend<.05, each). Longer vs. shorter mean bout duration was associated with higher risks for CVD (HR=1.54; CI=1.27-2.02; p-trend=0.003) after adjustment for covariates. Additional adjustment for CVD-risk biomarkers attenuated associations resulting in a quartile 4 vs. quartile 1 HR=1.36; CI=1.01-1.83; p-trend=0.10). Dose-response associations of sedentary time and bout duration with CVD were linear (P-nonlinear >0.05, each). Women jointly classified as having high sedentary time and long bout durations had significantly higher risk for CVD (HR=1.34; CI=1.08-1.65) than women with both low sedentary time and short bout duration. All analyses were repeated for incident coronary heart disease (MI or CVD death) and associations were similar with notably stronger hazard ratios. Both high sedentary time and long mean bout durations were associated in a dose-response manner with increased CVD risk in older women, suggesting that efforts to reduce CVD burden may benefit from addressing either or both component(s) of sedentary behavior.

Fitness Mediates Activity and Sedentary Patterns Associations with Adiposity in Youth.

We aimed to examine the cross-sectional associations of patterns of sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) with total fat mass index (FMI) and abdominal FMI (FMIabd) in children, and additionally, to analyze if cardiorespiratory fitness (CRF) mediated these associations. Fat mass index and FMIabd were assessed with dual-energy X-ray absorptiometry in 333 participants (172 girls) age 9 to 11 yr. MVPA, ST, breaks in ST per sedentary hour (BST/ST) and the number of daily sedentary bouts with various lengths (1-4, 5-9, 10-14, and ≥15 min) were assessed with accelerometry and CRF using a maximal cycle test. Hayes' PROCESS macro for SPSS was used for mediation analysis. The number of shorter sedentary bouts (1-4 min) was inversely associated with FMI (β = -0.108), whereas longer sedentary bouts (5-9 min, β = 0.169; 10-14 min, β = 0.193; ≥15 min, β = 0.377) had a positive association, independent of MVPA (P < 0.05). A similar trend was found for FMIabd. Moderate-to-vigorous physical activity was negatively related to FMI (β = -0.029) and to FMIabd (β = -0.003). There were no main associations for ST and BST/ST (P > 0.05). Cardiorespiratory fitness was inversely related to total and abdominal adiposity, and a large portion (40.9-65.7%) of the associations of MVPA and sedentary bouts with both FMI and FMIabd were mediated by CRF. Time in MVPA and accumulating ST in shorter sedentary bouts is inversely related to adiposity. However, these associations may be mediated by CRF. Emphasis should be given to programs that target increases in MVPA, which may influence CRF while reducing sedentary recreational behaviors.

Associations between activity patterns and cardio-metabolic risk factors in children and adolescents: A systematic review.

IntroductionTotal volumes of physical activity and sedentary behaviour have been associated with cardio-metabolic risk profiles; however, little research has examined whether patterns of activity (e.g., prolonged bouts, frequency of breaks in sitting) impact cardio-metabolic risk. The aim of this review was to synthesise the evidence concerning associations between activity patterns and cardio-metabolic risk factors in children and adolescents aged 5–19 years.Materials and methodsA systematic search of seven databases was completed in October 2017. Included studies were required to report associations between objectively-measured activity patterns and cardio-metabolic risk factors in children and/or adolescents, and be published between 1980 and 2017. At least two researchers independently screened each study, extracted data, and undertook risk of bias assessments.ResultsFrom the 15,947 articles identified, 29 were included in this review. Twenty-four studies were observational (cross-sectional and/or longitudinal); five were experimental. Ten studies examined physical activity patterns, whilst 19 studies examined sedentary patterns. Only one study examined both physical activity and sedentary time patterns. Considerable variation in definitions of activity patterns made it impossible to identify which activity patterns were most beneficial to children’s and adolescents’ cardio-metabolic health. However, potential insights and current research gaps were identified.Discussion and conclusionA consensus on how to define activity patterns is needed in order to determine which activity patterns are associated with children’s and adolescents’ cardio-metabolic risk. This will inform future research on the impact of activity patterns on children’s and adolescents’ short- and longer-term health.

Physical Activity and Sedentary Time Patterns in Children and Adolescents With Cystic Fibrosis and Age- and Sex-Matched Healthy Controls.

Regular physical activity (PA) is increasingly recognized as important in the care of patients with cystic fibrosis (CF), but there is a dearth of evidence regarding physical activity levels or how these are accrued in those with CF. PA was measured by a hip-worn accelerometer for 7 consecutive days in 18 children [10 boys; 12.4 (2.8) y] with mild to moderate CF and 18 age- and sex-matched controls [10 boys; 12.5 (2.7) y]. Both children with CF and healthy children demonstrated similar physical activity levels and patterns of accumulation across the intensity spectrum, with higher levels of PA during weekdays in both groups. Forced expiratory volume in 1second was predicted by high light PA in children with CF compared with low light PA in healthy children. These findings highlight weekends and light PA as areas warranting further research for the development of effective intervention strategies to increase PA in the youth CF population.

Patterns of sedentary time and ambulatory physical activity in a Danish population of girls and women with Rett syndrome

Background: Rett syndrome (RTT) is a rare neurodevelopmental disorder leading to multiple disabilities and high dependency on caregivers. This study aimed to: (1) describe the patterns of sedentary time and daily steps and (2) identify the association of individual and environmental characteristics with sedentary time.Methods: All Danish females with RTT older than 5 years of age and with a MECP2 mutation were invited to participate. The activPAL and StepWatch Activity Monitor (SAM) were worn by participants for at least four days. Sedentary time and step counts were plotted by time to examine daily activity patterns. Associations between sedentary time and individual and environmental covariates were assessed with linear regression models.Results: The median (interquartile range) age of participants was 22.0 (14.3–36.5) years. On average 83.3% (standard deviation 13.9%) of waking hours were spent in sedentary behaviours (n = 48) and the median (interquartile range) daily step count was 5128 (2829–7704) (n = 28). Females older than 33.5 years, and those unable to walk independently were more sedentary.Conclusions: This study demonstrated high levels of sedentary time and low daily step counts in a Danish population of females with RTT. Advancing age and lower walking skills were associated with higher levels of sedentary time.Implications for RehabilitationSedentary lifestyles in individuals with disabilities have a negative impact on health and quality of life.High levels of sedentary time and low daily step counts were demonstrated in a Danish population of females with Rett syndrome.Advancing age and inability to walk independently were strongly associated with higher levels of sedentary time in females with Rett syndrome.Understanding patterns of sedentary behaviour and physical activity can aid health care professionals in developing health-promoting physical activity interventions.