Total Sedentary Time Research Articles

Leisure Sedentary Time is Associated with Self-Reported Falls in Middle-aged and Older Females and Males: an Analysis of the CLSA.

The purpose of this analysis was to report the prevalence of falls and falls-related injuries among those reporting different volumes of weekly sedentary time, and to understand the association of sedentary time and falls, accounting for functional fitness. Baseline and first follow-up data from the Canadian Longitudinal Study on Aging (CSLA) were analyzed (n=22,942). Participants self-reported whether they had a fall in the past 12 months (at baseline) and whether they had an injury that was a result of a fall (follow-up). In-home interviews collected self-reported leisure sedentary time using the Physical Activity Scale for Elderly. Functional fitness was assessed using grip strength, timed-up-and-go, and chair rise tests during clinic visits. The prevalence of falls was higher among those who reported higher sedentary time. For example, among males aged 65 and older who reported lower sedentary time (<1,080 min/week), the prevalence of falls in the past 12 months (at baseline) was 7.8% compared to 9.8% in those reporting higher sedentary time. The odds of reporting a fall (at baseline) was 21% higher in those who reported higher sedentary time (OR: 1.21; 95%CI: 1.11-1.33) in adjusted models. No associations were found between sedentary time and injuries due to a fall. Reporting high volumes of sedentary time may increase the risk of falls. Future research using device-based estimates of total sedentary time and breaks in sedentary time is needed to further elucidate this association.

Behavioural activity pattern, genetic factors, and the risk of nonalcoholic fatty liver disease: A prospective study in the UK Biobank.

Physical activity, sedentary behaviour, and genetic variants have been associated with the nonalcoholic fatty liver disease (NAFLD). However, whether and how the degree of healthy activity patterns may modify the impact of genetic susceptibility on NAFLD remains unknown. Behaviour activity factors were determined according to total physical activity (TPA) and sedentary time. The polygenic risk score (PRS) was calculated by variants in PNPLA3, TM6SF2, MBOAT7, and GCKR. Cox regression was used to analyse the associations of genetic and behaviour activity factors with incident NAFLD in the UK Biobank (N = 338 087). During a median follow-up of 12.4 years, 3201 incident NAFLD cases were ascertained. Analyses of TPA and sedentary time simultaneously showed a dose-response association with the risk of NAFLD (ptrend < .001). The association of behaviour activity patterns with NAFLD varied by genetic variants. Of the subjects with high genetic risk, we observed a null protective effect of moderate or high TPA on NAFLD risk, while sitting less than three hours a day significantly decreased the risk of NAFLD (p = 3.50 × 10-4 ). The high genetic risk of NAFLD can also be offset by the combination of moderate physical activity and shorter sedentary time. Moreover, the high genetic risk group has the greatest reduction of 10-year absolute risk (6.95 per 1000 person-years) if reaching both healthy activities. Moderate-to-high physical activity and favourable sedentary behaviour may be lifestyle modifications in preventing NAFLD, which could offset the harmful effect of predisposing genetic factors.

Abstract MP69: Day-of-the-Week and Time-of-the-Day Temporal Patterns of Sedentary Behavior Among Hispanic / Latino Adults: Hispanic Community Health Study / Study of Latinos

Objectives: Existing sedentary behavior interventions have largely achieved modest results. Conventionally, interventions have attempted to reduce sedentary time using a full-day approach. An alternative strategy is to target specific periods when sedentary behavior is most prevalent. However, little is known when sedentary time is most likely to occur in adults. This study examined the day-of-the-week and time-of-the-day patterns of sedentary behavior among U.S. Hispanic/Latino adults. Methods: Participants (n=12,241) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a multi-site prospective cohort study of Hispanic/Latino adults, were studied. Sedentary time was measured for one week using a hip-mounted accelerometer. Three sedentary metrics were quantified: total sedentary time, sedentary time in bouts ≥ 60 minutes, and number of sedentary breaks. Results: Temporal patterns across days of the week were statistically significant for all three sedentary metrics (Figure, Panels A-C, p &lt; .001). Total sedentary time decreased from 719±2 mins/d on Mondays to 710±3 mins/d on Fridays the lowest and increased over weekends with Sundays (733±3 mins/d) the highest. Temporal patterns across 3-h periods of the day were statistically significant for all sedentary metrics (Figure, Panels D-F, p &lt; .001). Time-of-the-day patterns had a U-curve pattern wherein adults were most sedentary late at night, became less sedentary throughout the day, reached peak activeness around noon, then became more sedentary into the evening. Day-of-the-week and time-of-the-day patterns were robust across age, employment, work shift, and acculturation subgroups. Conclusions: Mornings, evenings, and weekends were the most sedentary periods in this cohort of Hispanic/Latino adults, characterized by higher volumes of sedentary time, more prolonged sedentary bouts, and fewer sedentary breaks. These time periods should be considered as important windows for behavioral interventions targeting sedentary behavior.

Influence of Volume and Bouts of Sedentary Time and Physical Activity on School-Aged Youth’s Physical Fitness: The UP &amp; DOWN Longitudinal Study

The aim of this study was to examine associations of total volume and bouts of sedentary time (ST) and moderate to vigorous physical activity (MVPA) with physical fitness (PF) in youth. This was a 2-year follow-up study with 1418 children and adolescents (51.7% boys). Accelerometers were used to assess ST and MVPA. Cardiorespiratory and muscular fitness values were objectively measured and combined in a global PF variable. Weight status was objectively obtained. Linear regression analyses were used to examine the cross-sectional (using scores at baseline) and longitudinal associations (using the change in the variables) of total volume and bouts of ST and MVPA with PF. Total ST was negatively associated with global PF (β = -0.488, P < .001 in cross-sectional analysis; β = -0.234, P = .003 in longitudinal analysis). However, this association was not independent of MVPA. Total volume of MVPA showed a positive association with global PF independently of ST and weight status (β = 0.285, P < .001 in cross-sectional analysis; β = 0.119, P = .001 in longitudinal analysis). Longitudinal associations found between ST and MVPA accumulated in bouts of various lengths and global PF became nonsignificant when their respective total volumes are included in the model. These results underline the need to accumulate minutes of MVPA, regardless of the bout duration, to increase PF levels in youth.

Longitudinal Analysis of Patterns and Correlates of Physical Activity and Sedentary Behavior in Women From Preconception to Postpartum: The Singapore Preconception Study of Long-Term Maternal and Child Outcomes Cohort.

Longitudinal changes in physical activity (PA) and sedentary behavior patterns from preconception to postpartum are not fully characterized. We examined changes and baseline sociodemographic/clinical correlates of PA and sedentary behavior in women from preconception to postpartum. The Singapore Preconception Study of Long-Term Maternal and Child Outcomes cohort recruited 1032 women planning pregnancy. Participants completed questionnaires at preconception, 34 to 36weeks gestation, and 12months postpartum. Repeated-measures linear regression models were used to analyze changes in walking, moderate to vigorous PA (MVPA), screen time, and total sedentary time, and to identify sociodemographic/clinical correlates associated with these changes. Of the 373 women who delivered singleton live births, 281 provided questionnaires for all time points. Walking time increased from preconception to late pregnancy but decreased postpartum (adjusted means [95% CI]: 454 [333-575], 542 [433-651], and 434 [320-547]min/wk, respectively). Vigorous-intensity PA and MVPA decreased from preconception to late pregnancy but increased postpartum (vigorous-intensity PA: 44 [11-76], 1 [-3-5], and 11 [4-19]min/wk, MVPA: 273 [174-372], 165 [95-234], and 226 [126-325]min/wk, respectively). Screen time and total sedentary time remained consistent from preconception to pregnancy but decreased postpartum (screen: 238 [199-277], 244 [211-277], and 162 [136-189]min/d, total: 552 [506-598], 555 [514-596], and 454 [410-498]min/d, respectively). Individual characteristics of ethnicity, body mass index, employment, parity, and self-rated general health significantly influenced women's activity patterns. During late pregnancy, walking time increased, while MVPA declined significantly, and partially returned to preconception levels postpartum. Sedentary time remained stable during pregnancy but decreased postpartum. The identified set of sociodemographic/clinical correlates underscores need for targeted strategies.

Sedentary Behaviour ‎and Sleeping Duration among Saudi Basketball Players ‎

Sedentary behaviour (SB) affects health and performance in highly trained athletes. A ‎number of research efforts have demonstrated that physical inactivity and SB are two ‎independent entities. However, SB in highly trained athletes in Saudi Arabia has not ‎been studied. Therefore, the aim of this study was to assess SB in Saudi basketball ‎players. Sixteen basketball players (mean ± Standard Deviation (SD), age, 22.6 ± 3.3 ‎years; body mass, 77.8 ± 10.5 kg; height, 182.9 ± 10.8 cm) participated in this study. A ‎self-report SB questionnaire was used to assess time spent on watching television, using ‎a computer/Internet, playing electronic games; total sedentary time; and sleep duration. ‎The cut-off point of ≥2 h/day was used to categories the outcome. Inadequate sleep ‎duration was defined as

Sedentary Behaviour-A Target for the Prevention and Management of Cardiovascular Disease.

Cardiovascular disease (CVD) is highly prevalent and can lead to disability and premature mortality. Sedentary behaviour, defined as a low energy expenditure while sitting or lying down, has been identified as an independent risk factor for CVD. This article discusses (1) the association of total sedentary time and patterns of accumulating sedentary time with CVD risk markers, CVD incidence and mortality; (2) acute experimental evidence regarding the acute effects of reducing and breaking up sedentary time on CVD risk markers; and (3) the effectiveness of longer-term sedentary behaviour interventions on CVD risk. Findings suggest that under rigorously controlled laboratory and free-living conditions, breaking up sedentary time improves cardiovascular risk markers in individuals who are healthy, overweight or obese, or have impaired cardiovascular health. Breaking up sedentary time with walking may have the most widespread benefits, whereas standing breaks may be less effective, especially in healthy individuals. There is also growing evidence that sedentary behaviour interventions may benefit cardiovascular risk in the longer term (i.e., weeks to months). Reducing and breaking up sedentary time may, therefore, be considered a target for preventing and managing CVD. Further research is needed to determine the effectiveness of sedentary behaviour interventions over the long-term to appropriately inform guidelines for the management of CVD.

Long sedentary time is associated with worsened cardiometabolic risk factors among university employees in Eastern Ethiopia

Sedentary time is associated with increased risks of detrimental health outcomes. Prolonged sedentary time associates with cardiometabolic risk factors and increased mortality regardless of physical activity. Therefore, the purpose of this study was to examine the associations of sedentary time and cardiometabolic risk factors among university employees in Eastern Ethiopia. A cross-sectional study was conducted among 1200 participants. Data were collected using the World Health Organization STEPS survey instrument, and sedentary behavior questionnaire in hour per day. Sedentary time is the time spent for any duration (minutes per day or hours per day) by considering a local context. Study participants were asked how many minutes or hours they spent in sedentary time at work, their leisure time and in transportation. Finally, the total sedentary time was calculated by the sum of the individual spent in sedentary time at work, leisure, and transportation. Cardiometabolic risk factors were assessed with blood samples analysis and anthropometric measurements. The associations between sedentary time and cardiometabolic risk factors were examined using linear regression models. An adjusted coefficient (β) with the 95% confidence interval (CI) was used to report the results. p value < 0.05 was considered for statistical significance. The mean age of the study participants were (35 ± 9.4 years). Almost half of the study participants, 566 (48.6) were women and 598 (51.4%) were men. As the total sedentary time was increased by one unit, the body mass index increased by β = 0.61; (95% CI 0.49–0.71),waist circumference increased by β = 1.48; (95% CI 1.14–1.82), diastolic blood pressure increased by β = 0.87; (95% CI 0.56–1.18), systolic blood pressure increased by β = 0.95; (95% CI 0.45–1.48), triglycerides increased by β = 7.07; (95% CI 4.01–10.14), total cholesterol increased by β = 3.52; (95% CI 2.02–5.02), fasting plasma glucose increased by β = 4.15; (95% CI 5.31–4.98) and low-density lipoprotein cholesterol increased by β = 2.14; (95% CI 0.96–3.33) with the effects of other variables maintain constant. These findings depict the need for strategies that policymakers should promote physical activity and encouraging the breaking up of prolonged sedentary time to reduce cardiometabolic risk factors among university employees in Ethiopia.

The impact of COVID-19 on sedentary behavior among Chinese university students：a retrospectively matched cohort study

Purpose: This study was to estimate the impact of COVID-19 on sedentary behavior for Chinese university students during the pandemic period, as well as explore how sedentary behavior changed as a function of gender.&#x0D; Methods: We conducted an online questionnaire (the Sedentary Behavior Questionnaire) on 1487 (947 males &amp; 513 females; Age 19.72± 1.32yr., BMI = 21.12 ± 4.50) students from one university in China during the pandemic period and students retrospectively recalled pre-pandemic physical activity levels (March 29- April 15, 2020). Sedentary behavior was measured using the short version of the Sedentary Behavior Questionnaire (SBQ). Sedentary behavior of social isolation in a typical week during the COVID-19 pandemic period and before the COVID-19 pandemic were measured based on SBQ. The data were analyzed using a paired-samples t-test. Chi-square tests were to compare categorical variables.&#x0D; Results: Before the COVID-19, on weekdays, survey participants averaged engaged in 11.41 (SD =3.93) hours of SB, 10.97 (SD = 3.85) hours of SB in males, 12.25 (SD =3.94) hours of SB in females; on weekends, survey participants averaged engaged in 13.18 (SD =4.06) hours of SB, 12.74 (SD = 3.96) hours of SB in males, 14.04 (SD =4.11) hours of SB in females. During the COVID-19, on weekdays, survey participants averaged engaged in 13.34 (SD =3.78) hours of SB, 12.90 (SD = 3.67) hours of SB in males, 14.19 (SD =3.83) hours of SB in females; on weekends, survey participants averaged engaged in 14.48 (SD =3.93) hours of SB, 14.10 (SD = 3.81) hours of SB in males, 15.22 (SD =4.04) hours of SB in females. Overall, on weekdays, COVID-19 on average appeared to increase SB by 1.93 (16.91%↑, 95% CI = 1.74, 2.12) hours, an increase in daily total SB by 1.92 (17.50%↑, 95% CI = 1.92, 2.15) hours for males, and an increase 1.94 (15.84%↑, 95% CI = 1.62, 2.27) hours in females. On weekends, COVID-19 on average appeared to increase SB by 1.30 (9.86%↑, 95% CI = 1.12, 1.48) hours, an increase in daily total SB by 1.36 (10.68%↑, 95% CI = 1.13, 1.58) hours for males, and an increase 1.18 (8.40%↑, 95% CI = 0.87, 1.50) hours in females.&#x0D; Conclusions: The COVID-19 led to an increase in sedentary behavior of Chinese university students. The total sedentary time of female students per week was higher than that of male students. Public policy action might be urgently needed to decrease the sedentary behavior of Chinese university students.

Associations between Accelerometer-Measured Physical Activity and Fecal Microbiota in Adults with Overweight and Obesity.

We aimed to assess whether total daily physical activity (PA), PA intensities, sedentary time (ST), and prolonged ST are associated with differences in the gut microbiota composition or short-chain fatty acid (SCFA) profile of adults with overweight or obesity. Cross-sectional associations between total daily PA (counts per minute), PA intensities (light and moderate-to-vigorous (MVPA)), ST, prolonged ST, and fecal microbiota composition were assessed in adults ( n = 124) between 25 and 45 yr of age with body mass index ≥25 kg·m -2 . Fecal microbiota composition was assessed with 16S rRNA gene sequencing. Daily PA and ST were measured with a hip-worn ActiGraph wGT3X-BT accelerometer. Daily PA volume and intensity were positively associated with relative abundance of Faecalibacterium ( P = 0.04) and negatively associated with the abundances of Alistipes , Parabacteroides , and Gemmiger ( P = 0.003-0.04) as well as the concentrations of acetate, butyrate, and total SCFA (all P = 0.04). Conversely, ST was negatively associated with abundance of Faecalibacterium but positively associated with the abundances of taxa, including Ruminococcaceae, Parabacteroides , Alistipes , and Gemmiger . Clustering of participants based on whether they met PA recommendations suggested that SCFA profiles differed between individuals who did and did not meet PA recommendations. K-means clustering based on percent of time spent in MVPA and ST also identified differences in fecal microbiota composition between cluster 1 (lower MVPA, higher ST) and cluster 2 (higher MVPA, lower ST), including a higher abundance of Alistipes in cluster 1. The current analysis suggests a beneficial association of daily PA on the fecal microbiota and a negative association of ST, particularly with respect to the associations of these variables with the genera Faecalibacterium , a butyrate-producing taxon.

DISTINCT PROFILES OF SEDENTARY BEHAVIORS IN OLDEST OLD ADULTS

Abstract Sedentary behavior (SB) is a significant health risk. Emerging research suggests that mentally active SB (such as computer use and reading) were associated with better health than mentally passive SB (such as watching TV). However, this has not been examined among the oldest old (age ≥80). The aims of this study were to (1) identify distinct profiles of oldest old adults based on six domains of SB (watching TV, using a computer/tablet, talking to friends or family members, doing hobby or other activities, transportation, and resting/napping); and (2) compare health-related outcomes across identified profiles, using the National Health and Aging Trends Study (NHATS) dataset. Latent profile analysis was used to identify distinct profiles of SB. Design-based linear and logistic regressions were used to examine associations between different profiles and health outcomes, accounting for sociodemographic characteristics. We identified four profiles and named them based on total sedentary time (ST) and passive/active pattern (n=852, “Low ST”, “High ST-passive”, “Medium ST-TV”, “High total ST-mentally active”). Compared to the “High ST-passive” group, “Low ST” group was associated with fewer difficulties with activities of daily living, fewer problems limiting activities and higher cognitive function; “High ST-mentally active” group was associated with the above outcomes, as well as lower anxiety and depression. This study, with a national representative sample of the oldest old population, suggests that both total ST and SB pattern matter when evaluating health outcomes of being sedentary. Interventions should encourage oldest old adults to reduce ST and especially target mentally passive ST.

PHYSICAL ACTIVITY AND SEDENTARY TIME ASSOCIATIONS WITH NON-FRACTURE FALL INJURY (NFFI) AND FRACTURE

Abstract Understanding fall injury risk factors and circumstances may lead to better prevention. However, many fall injury studies focus on fractures from hospitalizations or emergency events, rather than non-fracture fall injuries (NFFI), which comprise &amp;gt;50% of fall injuries in older adults. We hypothesized that risk factors were differently associated with NFFI vs. fracture fall injuries in a community-based cohort of ambulatory women with fall injuries in the Objective Physical Activity and Cardiovascular Disease Health in Older Women (OPACH) ancillary of the Women’s Health Initiative Long Life Study. Women with daily fall calendars over 1-year follow-up completed telephone interviews regarding fall injury circumstances (Nf662; mean 79.6 + 6.7 years; 73.3% White). Risk factors and fall circumstances were assessed with first reported fall injury (NFFI vs. fracture) using univariate and multivariate logistic regression. Participants with NFFI vs. fracture were more likely to be non-white, less likely to seek clinical treatment or need help up from fall (all p &amp;lt; 0.05). Adjusting for age, race, and BMI, NFFI vs. fracture were more likely to report &amp;gt;=6 hours sitting (OR=1.72, 95% CI=1.07–2.73) and less likely to report weekly moderate exercise (OR=0.61, 95% CI=0.38–0.96), though total accelerometer-measured sedentary time and physical activity (PA) were not significant. Self-reported PA level at the time of fall (OR=1.31, 95% CI=0.82–2.09) and walking outside for &amp;gt;10 minutes &amp;gt;= 1/week (OR=1.24, 95% CI=0.77–1.98) were not different for NFFI vs. fractures. Older women with NFFI vs. fracture had more sedentary time and less moderate exercise, which may have implications for fall injury severity.

Association of Accelerometer-Measured Sedentary Behavior Patterns With Nonalcoholic Fatty Liver Disease Among Older Adults: The MIND-China Study.

The relationships between sedentary behavior patterns and nonalcoholic fatty liver disease (NAFLD) in older adults are not well investigated. This population-based study included 1,899 rural-dwelling adults (aged 60 years or older). We assessed sedentary parameters with ActiGraph and defined NAFLD using ultrasonography. Long total and prolonged sedentary time were associated with increased likelihoods of NAFLD, whereas engaging more breaks per sedentary hour and reallocating sedentary time to light-intensity physical activity were associated with reduced likelihoods of NAFLD (P linear <0.05). Shorter sedentary time, engaging more frequent breaks in sedentary behavior, and replacing sedentary time with physical activity are associated with reduced likelihoods of NAFLD in older adults.

The association between sedentary behavioral characteristics and poor vision among Chinese children and adolescents.

To understand the features of sedentary behavior of Chinese children and adolescents and its relationship with poor visual acuity, a self-administered "Questionnaire on Sedentary Behavior of Children and Adolescents" was used to survey 4,203 students in grades 4-12 in six administrative regions of China. (1) The average time spent in sedentary behaviors (SB) of Chinese children and adolescents was about 8.1 h per day, of which the academic sedentary time was the longest, accounting for 79.2% of total sedentary time. The total time spent on SB and the time spent on studying SB were more in the upper grades and less in screen SB and cultural leisure SB, respectively. There were significant sex differences in total SB time (p < 0.05) and weekend sedentary behaviors time (SB-WD) (p < 0.01) among Chinese children and adolescents, with girls being more likely to be higher than boys. There were also significant differences in sedentary time across different regions (p < 0.05), and the longest total sedentary time in East China. (2) Reduction parents' sedentary time and limitation of sedentary behaviors and the use of electronics among children and adolescents can effectively reduce sedentary time among Chinese children and adolescents. (3) Sedentary time was significantly higher in children and adolescents with poor vision than in those with normal vision (p < 0.01), and study SB and screen SB were important independent factors affecting vision. (4) Timing of breaks in SB can play a positive role in promoting vision health. There were significant grade, sex, and regional differences in the SB of Chinese children and adolescents, and sedentary time was strongly related to the prevalence of poor vision detection rate.

Sedentary patterns and cardiometabolic risk factors in Mexican children and adolescents: analysis of longitudinal data

BackgroundSedentary behavior is a modifiable risk factor for cardiometabolic health; however, the assessment of total sedentary time may not capture youth’s highly active and interrupted activity patterns. This study examined the associations between sedentary activity patterns and cardiometabolic risk factors among Mexican youth, who have a disproportionate burden of metabolic diseases, using a repeated measure design out of a longitudinal data.Methods570 subjects in the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) birth cohort, who were followed up to three-time points during adolescence, were included. Bout duration, and frequency and percentages of waking time spent in specific intensities of activity, were quantified using ActiGraph wGT3X-BT wrist accelerometers. Self-reported questionnaires were used to query the usual duration of different sedentary behaviors. Outcomes were fasting lipid profile, markers for glucose homeostasis, anthropometry, and blood pressure. Associations were modeled using linear mixed-effects models, and isotemporal substitution approach was additionally used to assess the effect of replacing objectively assessed sedentary activity with other activity intensities, adjusting for potential confounders.ResultsEach hour of self-reported screen-based time was positively associated with diastolic blood pressure (mm Hg) [β = 0.30, 95% confidence interval (95% CI) = 0.10, 0.51], and an hour of other sedentary time was associated with log serum glucose (mg/dL) [β = 0.01, 95% CI = 0.004, 0.017]. Substitution models showed that replacing 5% of sedentary time with moderate to vigorous physical activity (MVPA) was associated with lower waist circumference (cm) [β = − 1.35, 95% CI = − 1.91, − 0.79] and log serum triglycerides (mg/dL) [β = − 0.11, 95% CI = − 0.18, − 0.03]. Substituting one uninterrupted sedentary bout with light activity was associated with lower insulin (μIU/mL) [β = − 0.06, 95% CI = − 0.10, − 0.02].ConclusionsSedentary time was associated with cardiometabolic risk factors in Mexican youth in a context-specific manner. Replacing sedentary time with higher intensities was associated with improvements in some cardiometabolic markers.

Correlates of domain-specific sedentary behaviors and objectively assessed sedentary time among elementary school children

Understanding the correlates of sedentary behavior among children is essential in developing effective interventions to reduce sitting time in this vulnerable population. This study aimed to identify correlates of domain-specific sedentary behaviors and objectively assessed sedentary time among a sample of children in Japan. Data from 343 children (aged 6–12 years) living in Japan were used. Domain-specific sedentary behaviors were assessed using a questionnaire. Total sedentary time was estimated using hip-worn accelerometers. Twenty-two potential correlates across five categories (parental characteristics, household indoor environment, residential neighborhood environment, school environment, and school neighborhood environment) were included. Multivariable linear regression models were used to identify correlates of domain-specific sedentary behaviors and objectively assessed sedentary time. Eight correlates were significantly associated with children’s domain-specific sedentary behaviors: mother’s and father’s age, mother’s educational level, having a video/DVD recorder/player, having a video console, having a TV one’s own room, home’s Walk Score®, and pedestrian/cycling safety. No significant associations were found between potential correlates and accelerometer-based total sedentary time. These findings highlight that strategies to reduce children’s sedentary time should consider the context of these behaviors. For example, urban design attributes such as perceived pedestrian and cycling safety can be improved to reduce children’s car sitting time.

Timing of physical activity in relation to liver fat content and insulin resistance

Aims/hypothesisWe hypothesised that the insulin-sensitising effect of physical activity depends on the timing of the activity. Here, we examined cross-sectional associations of breaks in sedentary time and timing of physical activity with liver fat content and insulin resistance in a Dutch cohort.MethodsIn 775 participants of the Netherlands Epidemiology of Obesity (NEO) study, we assessed sedentary time, breaks in sedentary time and different intensities of physical activity using activity sensors, and liver fat content by magnetic resonance spectroscopy (n=256). Participants were categorised as being most active in the morning (06:00–12:00 hours), afternoon (12:00–18:00 hours) or evening (18:00–00:00 hours) or as engaging in moderate-to-vigorous-physical activity (MVPA) evenly distributed throughout the day. Most active in a certain time block was defined as spending the majority (%) of total daily MVPA in that block. We examined associations between sedentary time, breaks and timing of MVPA with liver fat content and HOMA-IR using linear regression analyses, adjusted for demographic and lifestyle factors including total body fat. Associations of timing of MVPA were additionally adjusted for total MVPA.ResultsThe participants (42% men) had a mean (SD) age of 56 (4) years and a mean (SD) BMI of 26.2 (4.1) kg/m2. Total sedentary time was not associated with liver fat content or insulin resistance, whereas the amount of breaks in sedentary time was associated with higher liver fat content. Total MVPA (−5%/h [95% CI −10%/h, 0%/h]) and timing of MVPA were associated with reduced insulin resistance but not with liver fat content. Compared with participants who had an even distribution of MVPA throughout the day, insulin resistance was similar (−3% [95% CI −25%, 16%]) in those most active in morning, whereas it was reduced in participants who were most active in the afternoon (−18% [95% CI −33%, −2%]) or evening (−25% [95% CI −49%, −4%]).Conclusions/interpretationThe number of daily breaks in sedentary time was not associated with lower liver fat content or reduced insulin resistance. Moderate-to-vigorous activity in the afternoon or evening was associated with a reduction of up to 25% in insulin resistance. Further studies should assess whether timing of physical activity is also important for the occurrence of type 2 diabetes.Graphical abstract

Bidirectional associations of accelerometer-assessed physical activity and sedentary time with physical function among older English adults: the EPIC-Norfolk cohort study

To develop healthy ageing interventions, longitudinal associations between objectively assessed physical behaviours and physical function need to be better understood. We assessed associations between accelerometer-assessed total physical activity (PA), moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), sedentary time and prolonged sedentary bout time, and clinically assessed physical function (grip strength, usual walking speed (UWS), chair stand speed) at two time-points in 3188 participants (≥ 60 years) of the EPIC-Norfolk study. Bidirectional associations were assessed using multivariable linear regression. Over an average of 6.1 years, baseline physical behaviours (greater total PA, MVPA and LPA, and less sedentary time) were associated with better subsequent walking and chair stand speed. Better baseline physical function was associated with better follow-up physical behaviours. There were no bidirectional associations between changes in physical behaviours and grip strength. Improvements in UWS were associated with improvements in all physical behaviours. Improvements in chair stand speed were associated with improvements in total PA, MVPA, and sedentary bout time. Improvements in physical behaviours were associated with improvements in UWS (3.1 cm/s/yr per 100 cpm/yr total PA, 3.6 cm/s/yr per hr/day/yr MVPA, 2.5 cm/s/yr per hr/day/yr LPA, − 2.9 cm/s/yr per hour/day/yr sedentary time, and − 1.6 cm/s/yr per hr/day/yr prolonged sedentary bout time). Only improvements in total PA, MVPA and sedentary bout time were associated with improvements in chair stand speed. In conclusion, we found bidirectional associations between changes in some physical behaviours and physical function and between baseline physical behaviours and subsequent physical function, highlighting the importance of considering the full range of physical behaviours to promote healthy ageing.

Screen-based sedentary behaviors but not total sedentary time are associated with anxiety among college students.

The purpose of the study was to investigate the associations of device-measured total sedentary time and screen-based sedentary time with anxiety in college students. Three hundred and twenty-one college students (mean age = 19.72 ± 1.18, 55.8% females) were recruited from Shanghai, China. Total sedentary time was objectively measured using accelerometry, while screen-based sedentary time was self-reported. Anxiety symptom was evaluated using the Self-Rating Anxiety Scale. Linear regression modeling was used to assess the associations of total sedentary time and screen-based sedentary time with anxiety symptom. Accelerometer-assessed total sedentary time was not associated with anxiety symptom. Prolonged sedentary time on TV and movie viewing (>2 h on weekdays) and social media using (>2 h on weekdays and weekend) were associated with a higher level of anxiety. However, time on video gaming and recreational reading was not associated with anxiety symptom. The findings indicated that screen-based sedentary behaviors but not total sedentary time were associated with anxiety symptom among college students. The associations of screen-based sedentary behaviors with anxiety symptom varied by the types of screen time.

Sedentary time and the risk of metabolic syndrome: A systematic review and dose–response meta‐analysis

The dose-response association between sedentary time and the risk of metabolic syndrome is unclear, which indicates an important knowledge gap in public health. The objective of this study was to determine the categorical and continuous dose-response associations between sedentary time and the risk of metabolic syndrome. A systematic literature search of English articles published in PubMed, CINHAL, Embase, and Web of Science Core Collection prior to June 2022 was conducted. All cohort and cross-sectional studies that examined the association between sedentary time and the risk of metabolic syndrome were considered, and duplicate and non-related studies were excluded. Data extraction using a standardized chart and quality assessment using two appraisal tools were also performed. Two independent reviewers were involved in these processes. In categorical meta-analyses, the pooled effect sizes for metabolic syndrome associated with different categories of sedentary time were calculated by comparing the highest and intermediate with the lowest categories. In continuous meta-analyses, the linear and nonlinear dose-response associations were estimated using generalized least squares and restricted cubic spline models, respectively. Data were collected and analyzed from March to June 2022. Four prospective cohort studies and 22 cross-sectional studies with 105,239 participants and 16,185 MetS cases were included in this study. In categorical analyses, both intermediate (median duration: 4.11 h/day; pooled OR: 1.17, 95% CI: 1.08-1.26, P&lt; 0.001) and high levels (median duration: 7.26 h/day; pooled OR: 1.71, 95% CI: 1.43-2.04, P&lt; 0.001) of total sedentary time were significantly associated with an increased risk of metabolic syndrome. Similarly, a significant association between screen time and the risk of metabolic syndrome was also found in intermediate (median duration: 2.22 h/day; pooled OR: 1.20, 95% CI: 1.10-1.32, P&lt; 0.001) and high levels (median duration: 3.40 h/day; pooled OR: 1.63, 95% CI: 1.44-1.86, P&lt; 0.001) of exposure. Of note, these associations were significantly stronger in women. Different patterns of the behavior-disease association were not observed in children, adolescents, and adults. The findings of continuous meta-analyses could not provide solid evidence for the linearity and nonlinearity of the behavior-disease association. This study demonstrated that long-time sedentary behavior was associated with a higher risk of MetS independent of physical activity and the patterns of association varied by gender instead of age. These findings have implications for future guideline recommendations on physical activity, sedentary behavior, and prevention of metabolic syndrome.