Patterns of sedentary time and cardiometabolic risk among Canadian adults

ObjectiveThe aim of this study is to examine the associations of total sedentary time and patterns of sedentary time with cardiometabolic biomarkers in a large representative sample of Canadian adults.MethodsThe study is based on 4935 adults aged 20–79 years, from the 2007/09 and 2009/11 Canadian Health Measures Survey. Total sedentary time, patterns of sedentary time (≥ 20 minute prolonged sedentary bouts, number of sedentary breaks), and moderate- to vigorous-intensity physical activity (MVPA) were accelerometer-derived. Waist circumference, systolic and diastolic blood pressure, high-density lipoprotein (HDL) cholesterol, and C-reactive protein were measured. Triglycerides, low-density lipoprotein (LDL) cholesterol, insulin, and glucose were also measured in a fasting sub-sample (n = 2551).ResultsTotal sedentary time and time in ≥ 20 minute prolonged sedentary bouts were associated with higher insulin and lower diastolic blood pressure levels (P < 0.05). On average, each additional 10 breaks/day was associated with 0.83 (95%CI: 1.35, 0.31) cm lower waist circumference, 0.32 (0.62, 0.02) mm Hg lower systolic blood pressure, 0.01 (0.00, 0.02) mmol/l higher HDL-cholesterol, 3.72 (1.34, 6.13) % lower triglycerides, 0.57 (0.23, 0.92) % lower glucose, and 4.19 (1.80, 6.63) % lower insulin.ConclusionThese findings in a large representative sample of Canadian adults indicate that breaking up sedentary time may be particularly important for cardiometabolic health.     

Joint effects of objectively-measured sedentary time and physical activity on all-cause mortality

ObjectiveExamine the joint effects of objectively-measured sedentary time and moderate-to-vigorous physical activity (MVPA) on all-cause mortality.MethodsThe present study included data from the 2003–2006 National Health & Nutrition Examination Survey, with mortality follow-up data (via National Death Index) through 2011 (N = 5575 U.S. adults). Sedentary time (activity counts/min between 0 and 99) and MVPA (activity counts/min ≥ 2020) were objectively measured using the ActiGraph 7164 accelerometer.ResultsThe median age of the participants was 50 yrs; proportion of men was 50.2%; proportion of whites was 53.8%, 18.7% for blacks; median follow-up was 81 months; and 511 deaths occurred over the follow-up period. After adjusting for age, gender, race-ethnicity, cotinine, weight status, poverty level, C-reactive protein and comorbid illness (summed score of 0–8 chronic diseases), and for a 1 min increase in MVPA and sedentary time, both MVPA (HR_adjusted = 0.98; 95% CI: 0.96–0.99; P = 0.04) and sedentary time (HR_adjusted = 1.001; 95% CI: 1.0003–1.002; P = 0.008) were independently associated with all-cause mortality. Further, MVPA was associated with all-cause mortality among those with greater (above median) sedentary time (HR_adjusted = 0.95; 95% CI: 0.93–0.97; P < .001). Sedentary time was not associated with all-cause mortality among those engaging in above median levels of MVPA (HR_adjusted = 0.998; 95% CI: 0.996–1.001; P = .32), but sedentary time was associated with increased mortality risk among those below median levels of MVPA (HR = 1.002; 95% CI: 1.001–1.003; P < 0.001).ConclusionsSedentary time and MVPA are independently associated with all-cause mortality. Above median sedentary time levels did not negate the beneficial effects of MVPA on all-cause mortality risk.     

The effects of shift work on free-living physical activity and sedentary behavior

ObjectiveAlthough occupation may influence physical activity and shift work schedule may influence cardiovascular disease risk factors, our understanding of the effects of shift work schedule on overall physical activity behavior and sedentary behavior is limited.MethodsData from the 2005–2006 National Health and Nutrition Examination Survey were used. Shift work schedule was defined as regular daytime shift, evening, night, rotating or another schedule. Physical activity and sedentary behavior were assessed via accelerometry. 1536 adult participants (≥ 20 years) indicated they currently work and provided data on all study variables.ResultsAfter adjustments, and compared to adults working a regular daytime shift, those working an evening (RR = 0.41, p = 0.001) and night (RR = 0.30, p = 0.001) shift, respectively, engaged in 59% and 70% less sustained (bouts) moderate-to-vigorous physical activity, but no differences occurred for overall moderate-to-vigorous physical activity. After adjustments, and compared to those working a regular daytime shift, those working a rotating shift engaged in more light-intensity physical activity (overall: β = 26.3 min/day; p = 0.03; bouts: β = 37.5, p = 0.01) and less sedentary behavior (β = − 28.5 min/day, p = 0.01).ConclusionsShift work schedule differentially influences physical activity and sedentary behavior. Physical activity and sedentary intervention strategies may need to be tailored based on shift work schedule.     

Associations between physical activity,sedentary time,sleep duration and daytime sleepiness in US adults

ObjectiveTo examine the associations between objectively measured physical activity (PA) or sedentary behavior and self-reported sleep duration or daytime sleepiness in a nationally representative sample of healthy US adults (N = 2128).MethodsWe report analyses of four aspects of sedentary behavior and PA derived from accelerometry data (minutes of sedentary time, activity counts/minute, Minutes of Moderate and Vigorous PA [MVPA], and MVPA in 10-minute bouts) versus self-report of sleep duration and frequency of daytime sleepiness from the 2005–2006 National Health and Nutrition Examination Survey.ResultsAge and sex dependence of associations between PA and sleep were observed. Aspects of PA were significantly lower in adults reporting more frequent daytime sleepiness in younger (20–39) and older (≥ 60) age groups, but not in middle-aged (40–59), respondents. In younger respondents, PA increased with sleep duration, but in middle aged and older respondents PA was either unrelated to sleep duration or lower in those reporting ≥ 8 h of sleep. Objectively measured sedentary time showed limited evidence of associations with sleep duration.ConclusionsFurther research delineating the relationships between sleep and PA is important because both activities have been implicated in diverse health outcomes as well as in the etiology of obesity.     

Physically active vs. sedentary academic lessons: A dose response study for elementary student time on task

BackgroundPhysically active academic lessons are an effective intervention to reduce sedentary time and increase student physical activity. They have also been shown to enhance task engagement, as indicated by observations of attention and behavior control, time on task (TOT). However, it is not clear if the improved TOT stems from the physical activity or if it is the result of an enjoyable break from traditional instruction. If it is due to physical activity, what dose of intensity is required for the effect? This study was designed to test these questions.MethodsParticipants were 320 children (7–9 years) recruited from school districts in Central Texas in 2012. They were assigned by classroom (n = 20) to one of four conditions: 1) sedentary, standard lesson (n = 72); 2) sedentary academic game (n = 87); 3) low to moderate intensity PA (LMPA), academic game (n = 81); and 4) moderate to vigorous intensity PA (MVPA), academic game (n = 76). Measures included PA via accelerometer and TOT.ResultsMixed-method RMANOVA indicated TOT decreased following the standard lesson (p < 0.001), showed no change following the sedentary academic game (p = 0.68), and increased following the LMPA (p < 0.01) and MVPA (p < 0.001) academic games.ConclusionsWhile the sedentary, academic game prevented the reduction in TOT observed in the standard lesson, PA resulted in increased TOT. Future research should be designed to examine the potential academic benefits of the change in TOT.     

Association between compliance with physical activity guidelines,sedentary behavior and depressive symptoms

Physical inactivity, i.e. not engaging in adequate moderate-to-vigorous physical activity (MVPA), has been identified as a risk factor for depression. Increased sedentary time has further been identified as a potential risk factor for depression. We analyzed NHANES 2005–2006 data to examine the associations between compliance with physical activity guidelines (PAG) and sedentary time with depression. We utilized accelerometer data to assess compliance with PAG and sedentary time, and we used the Patient Health Questionnaire (PHQ-9) to assess presence of depression. Participants were classified as compliant with PAG or non-compliant based on MVPA accumulated in bouts of 10 min or more. We further divided these two groups into quartiles of sedentary time. We conducted logistic regression analyses to test for the interaction effect of PAG compliance and sedentary behavior on depression. Analyses were conducted in 2014–2015 at the University of Illinois at Urbana-Champaign. Mean depression score among compliant participants was 1.65 (SD = 2.61), whereas it was higher among the non-compliant participants (mean = 2.52, SD = 3.51). Logistic regression indicated a statistically significant interaction effect between MVPA and sedentary time on depression scores. There was no apparent trend in depression scores across quartiles of sedentary time in the compliant group. However, adjusted odds ratios for depression increased with increasing sedentary time among the non-compliant group. We provide evidence that compliance with PAG is associated with reduced depressive symptoms regardless of sedentary behavior; however, increased sedentary behavior may increase the risk of depression among those who are not physically active at a level which meets national guidelines.     

The effects of objectively measured sedentary behavior on all-cause mortality in a national sample of adults with diabetes

BackgroundDiabetes is a highly prevalent chronic disease that has been increasing globally and is the seventh leading cause of death in the United States. Sedentary behavior is associated with increased risk of diabetes and is unfavorably related to all-cause mortality, but there are limited studies examining the sedentary–mortality relationship among those with diabetes, which was the purpose of this study.MethodsUsing data from the 2003–2006 NHANES, 712 adult participants with evidence of diabetes had complete data on the study variables. A multivariable Cox proportional hazard model was used to examine the association between objectively measured sedentary behavior and all-cause mortality among this diabetic sample.ResultsResults showed that for every 60 min/day increase in sedentary behavior, independent of moderate-to-vigorous physical activity (MVPA) and other covariates, adults with diabetes had a 13% increased risk of all-cause mortality (HR_adjusted = 1.13; 95% CI = 1.03–1.24; P = 0.01). However, after adjusting for total physical activity (light and MVPA), sedentary behavior was no longer associated with mortality risk (HR_adjusted = 1.04; 95% CI = 0.92–1.16; P = 0.46).ConclusionAmong those with diabetes, sedentary behavior may not have increased mortality risk independent of total physical activity behavior.     

Accelerometer-measured sedentary time and cardiometabolic biomarkers: A systematic review

ObjectiveWe conducted a systematic review to investigate the cross-sectional and prospective associations of accelerometer-measured total sedentary time and breaks in sedentary time with individual cardiometabolic biomarkers in adults ≥ 18 years of age.MethodsOvid Medline, Embase, Web of Science and the Cochrane Library were searched for studies meeting the inclusion criteria. Due to inconsistencies in the measurement and analysis of sedentary time, data was synthesised and presented narratively rather than as a meta-analysis.ResultsTwenty-nine studies were included in the review; twenty-eight reported on total sedentary time and six on breaks in sedentary time. There was consistent evidence from cross-sectional data of an unfavourable association between total sedentary time and insulin sensitivity. There was also some evidence that total sedentary time was unfavourably associated with fasting insulin, insulin resistance and triglycerides. Furthermore, there was some evidence from cross-sectional data of a favourable association between breaks in sedentary time and triglycerides.ConclusionTotal sedentary time was consistently shown to be associated with poorer insulin sensitivity, even after adjusting for time spent in physical activity. This finding supports the proposed association between sedentary time and the development of Type 2 diabetes and reinforces the need to identify interventions to reduce time spent sedentary.     

Objectively assessed physical activity,fitness and subjective wellbeing

BackgroundThe existing evidence for a cross-sectional association between physical activity and subjective wellbeing is inconsistent, mainly because of the reliance on self reported physical activity, which might have conceptual overlap with subjective health.PurposeTo examine associations of objectively assessed physical activity and cardiorespiratory fitness with subjective wellbeing.MethodsA sub-sample of participants (921 men and women, mean age 44.6 ± 15.0 yrs, 46.4% men) from the 2008 Health Survey for England completed objective measures of physical activity (Actigraph) and an 8 min sub-maximal step test to estimate levels of cardiorespiratory fitness. The General Health Questionnaire and self-rated health was used as indicators of subjective wellbeing.ResultsThe recorded levels of moderate to vigorous physical activity (MVPA) were higher in participants reporting very good health (adjusted mean difference = 6.7, 95% CI, 1.1–12.4 min/d, p = 0.019) compared with participants reporting fair–poor health after adjustment for various confounders and fitness level. Neither physical fitness, objectively assessed sedentary time or light activity was related to self-rated health. There was also no association between objectively measured physical activity and fitness with psychological health, despite a robust association with self reported MVPA in the overall sample.ConclusionsObjectively assessed MVPA is independently associated with self-rated health. Self reported, but not objectively assessed MVPA, was associated with psychological health. The null findings with regards to psychological health might partly reflect selection biases associated with the healthy nature of this sub-sample of participants.     

Accelerometer determined sedentary behavior and dietary quality among US adults

ObjectiveScant evidence exists pertaining to objectively measured sedentary time and dietary quality among adults. Therefore, we examined the relationships between sedentary time, physical activity, and dietary quality.MethodsCross-sectional analyses of a 4,910 US adults from two cycles (2003–2006) of the National Health and Nutrition Examination Survey. The primary independent variables were sedentary time and physical activity (continuous and categorical), while the outcomes were overall dietary quality (Healthy Eating Index (HEI) 2010), fruit and vegetable scores, and empty caloric intake (kcal).ResultsMultivariable analyses revealed that a 1 min increase in daily sedentary behavior was associated with a 0.2 kcal decrease in empty calories (− 0.18, 95% CI = − 0.34, − 0.03); however, sedentary time was not significantly related to overall dietary quality (HEI) and fruit and vegetable intake. In comparison, a 1 min increase in daily moderate-to-vigorous intensity physical activity was related to a 0.1 higher HEI score (0.08, 95% CI = 0.04, 0.11), a 0.01 higher fruit score (0.01, 95% CI = 0.01, 0.02), and conversely a 1.3 kcal decrease in empty calories (− 1.35, 95% CI = − 2.01, − 0.69). In addition, meeting physical activity guidelines was associated with a 2.8 point higher HEI score (2.82, 95% CI = 1.40, 4.25), a 0.5 point higher fruit score (0.51, 95% CI = 0.31–0.71), and 37.4 fewer empty calories (− 37.43, 95% CI = − 64.86, − 9.10).ConclusionsPhysical activity is significantly related to better overall dietary quality, while sedentary behavior is not. Findings suggest the need to promote physical activity and encourage adherence to dietary guidelines jointly, whereas sedentary behavior and overall dietary quality might need to be targeted independently.     

Spatial analysis of crime incidence and adolescent physical activity

ObjectivesAdolescents do not achieve recommended levels of physical activity. Crime is believed to be a barrier to physical activity among youth, but findings are inconsistent. This study compares the spatial distribution of crime incidences and moderate-to-vigorous physical activity (MVPA) among adolescents in Massachusetts between 2011 and 2012, and examines the correlation between crime and MVPA.MethodsEighty adolescents provided objective physical activity (accelerometer) and location (Global Positioning Systems) data. Crime report data were obtained from the city police department. Data were mapped using geographic information systems, and crime and MVPA densities were calculated using kernel density estimations. Spearman's correlation tested for associations between crime and MVPA.ResultsOverall, 1694 reported crimes and 16,702 min of MVPA were included in analyses. A strong positive correlation was present between crime and adolescent MVPA (ρ = 0.72, p < 0.0001). Crime remained positively associated with MVPA in locations falling within the lowest quartile (ρ = 0.43, p < 0.0001) and highest quartile (ρ = 0.32, p < 0.0001) of crime density.ConclusionsThis study found a strong positive association between crime and adolescent MVPA, despite research suggesting the opposite relationship. This counterintuitive finding may be explained by the logic of a common destination: neighborhood spaces which are desirable destinations and promote physical activity may likewise attract crime.     

Associations of objectively-assessed physical activity and sedentary time with depression: NHANES (2005-2006)

BackgroundStudies provide conflicting evidence for the protective effects of moderate-to-vigorous-intensity physical activity on depression. Recent evidence suggests that sedentary behaviors may also be associated with depression.PurposeTo examine the associations of accelerometer-derived moderate-to-vigorous-intensity physical activity and sedentary time with depression among a population-based sample.MethodsCross-sectional study using 2,862 adults from the 2005–2006 US National Health and Nutrition Examination Survey. ActiGraph accelerometers were used to derive both moderate-to-vigorous-intensity physical activity and sedentary time.ResultsDepression occurred in 6.8% of the sample. For moderate-to-vigorous-intensity physical activity, compared with those in quartile 1 (least active), significantly lower odds of depression were observed for those participants in quartiles 2 (OR = 0.55, 95% CI, 0.34 to 0.89), 3 (OR = 0.49, 95% CI, 0.26 to 0.93), and 4 (most active) (OR = 0.37, 95% CI, 0.20 to 0.70) (p for trend p < 0.01). In overweight/obese participants only, those in quartile 4 (most sedentary) had significantly higher odds for depression than those in quartile 1 (least sedentary) [quartile 3 vs 1 (OR = 1.94, 95% CI, 1.01 to 3.68) and 4 vs 1 (OR = 3.09, 95% CI, 1.25 to 7.68)].ConclusionThe current study identified lower odds of depression were associated with increasing moderate-to-vigorous-intensity physical activity and decreasing sedentary time, at least within overweight/obese adults.     

Neighborhood environmental attributes and adults' sedentary behaviors: Review and research agenda

ObjectivePhysical activity recommendations are beginning to address sedentary behaviors – time spent sitting. Environmental and policy initiatives for physical activity might assist in addressing sedentary behaviors, but sedentary-specific innovations may be required. This review synthesizes current evidence on associations of neighborhood environmental attributes with adults' sedentary behaviors.MethodsA search was conducted using three electronic databases (PubMed, Web of Science, and Transport Research Information Services). Relevant articles were assessed for their eligibility for inclusion (English-language articles with a quantitative examination of associations of neighborhood environmental attributes with adults' sedentary behaviors).ResultsWithin 17 studies meeting inclusion criteria, associations of environmental attributes with sedentary behaviors were examined in 89 instances. Significant associations were found in 28% (n = 25) of them; however, non-significant associations were found in 56% (n = 50) of these instances. The most consistent association was for lower levels of sedentary behavior among residents of urban compared to regional areas.ConclusionsThere is a modest but mixed initial evidence in associations of neighborhood environmental attributes with adults' sedentary behaviors. A research agenda required for this emerging field should include the development of more relevant conceptual models, measuring domain-specific sedentary behavior objectively, examining environments in close vicinity of and a larger area around home, and the use of prospective designs.     

Objectively measured physical activity,sedentary time and subclinical vascular disease: Cross-sectional study in older British men

Low physical activity (PA) and high levels of sedentary time (ST) are associated with higher cardiovascular disease (CVD) risk among older people. However, their independent contribution and importance of duration of PA and ST bouts remain unclear. We investigated associations between objectively measured PA, ST and non-invasive vascular measures, markers of CVD risk.Cross-sectional study of 1216 men from the British Regional Heart Study, mean age 78.5 years, measured in 2010–2012. Carotid intima thickness (CIMT), distensibility coefficient (DC) and plaque presence were measured using ultrasound; pulse wave velocity (cfPWV) and augmentation index (AIx) using a Vicorder. PA and ST were measured using hip-worn ActiGraph GT3X accelerometers.After adjusting for covariates, each additional 1000 steps per day was associated with a 0.038 m/s lower cfPWV (95% CI = − 0.076, 0.0003), 0.095 10^− 3 kPa^− 1 higher DC (95% CI = 0.006, 0.185), 0.26% lower AIx (95% CI = − 0.40, − 0.12) and a 0.005 mm lower CIMT (95% CI = − 0.008, − 0.001). Moderate and vigorous PA (MVPA) was associated with lower AIx and CIMT, light PA (LPA) with lower cfPWV and CIMT and ST with higher cfPWV, AIx and CIMT and lower DC. LPA and ST were highly correlated (r = − 0.62). The independence of MVPA and ST or MVPA and LPA was inconsistent across vascular measures. Bout lengths for both PA and ST were not associated with vascular measures.In our cross-sectional study of older men, all PA regardless of intensity or bout duration was beneficially associated with vascular measures, as was lower ST. LPA was particularly relevant for cfPWV and CIMT.     

Executive function mediates prospective relationships between sleep duration and sedentary behavior in children

Childhood sedentary behavior has been linked to increased obesity risk. Prior work has identified associations between sedentary behavior, executive function (EF), and sleep. This study tested the hypothesis that reduced sleep duration may adversely impact EF and lead to increased childhood sedentary behavior. Southern California schoolchildren participating in the school-based health promotion program Pathways to Health (N = 709) were assessed annually from 4th through 6th grades (2010 − 2013) on self-report measures of sedentary behavior, sleep duration, and executive function. A series of path models were specified treating average nightly sleep duration and weekend wake/bed-time shift at 4th grade as predictors of 6th grade sedentary behavior. Four EF subdomains were tested as potential mediators of longitudinal associations at 5th grade. Significant associations between average nightly sleep duration, EF and sedentary behavior were identified (p < 0.05), adjusting for participant gender, physical activity, SES, ethnicity, program group assignment, and the presence/absence of parental screen time rules. Fifth grade overall EF (p < 0.05)—and in particular the subdomains of inhibitory control (p < 0.05) and organization of materials (p < 0.01)—significantly mediated the relationship between 4th grade sleep duration and 6th grade sedentary behavior (p < 0.05). Furthermore, delay of weekend bed- or wake-times relative to weekdays was prospectively associated with decreased overall EF (p < 0.05), but not increased sedentary behavior (p = 0.35 for bed-time delay; p = 0.64 for wake-time delay), irrespective of average nightly sleep duration. Findings suggest that sleep promotion efforts may reduce children's sedentary behavior both directly and indirectly through changes in EF.     

Implementing classroom physical activity breaks: Associations with student physical activity and classroom behavior

ObjectiveTo investigate the relation of classroom physical activity breaks to students' physical activity and classroom behavior.MethodsSix elementary-school districts in California implemented classroom physical activity interventions in 2013–2014. Students' (N = 1322) accelerometer-measured moderate-to-vigorous physical activity (MVPA) during school and teachers' (N = 397) reports of implementation and classroom behavior were assessed in 24 schools at two time points (both post-intervention). Mixed-effects models accounted for nested data.ResultsMinutes/day of activity breaks was positively associated with students' MVPA (βs = .07–.14; ps = .012–.016). Students in classrooms with activity breaks were more likely to obtain 30 min/day of MVPA during school (OR = 1.75; p = .002). Implementation was negatively associated with students having a lack of effort in class (β = − .17; p = .042), and student MVPA was negatively associated with students being off task or inattentive in the classroom (β = − .17; p = .042). Students provided with 3–4 physical activity opportunities (classroom breaks, recess, PE, dedicated PE teacher) had ≈ 5 more min/day of school MVPA than students with no opportunities (B = 1.53 min/opportunity; p = .002).ConclusionsImplementing classroom physical activity breaks can improve student physical activity during school and behavior in the classroom. Comprehensive school physical activity programs that include classroom-based activity are likely needed to meet the 30 min/day school physical activity guideline.     

Daily movement patterns and predicted 10-yr risk for a first atherosclerotic cardiovascular disease (ASCVD) event using the pooled cohort risk equations among US adults

ObjectiveExamine the association between movement patterns and predicted risk of a first atherosclerotic cardiovascular disease (ASCVD) event.MethodsData from the 2003–2006 National Health and Nutrition Examination Survey (NHANES) were used (40–79 yrs; N = 2421). Participants wore an ActiGraph 7164 accelerometer to create four movement pattern groups; Group 1: ≥ 150 min/wk of moderate-to-vigorous physical activity (MVPA) and light-intensity physical activity (LIPA) ≥ sedentary behavior (SB); Group 2: ≥ 150 min/wk of MVPA and LIPA < SB; Group 3: < 150 min/wk of MVPA and LIPA ≥ SED; and Group 4: < 150 min/wk of MVPA and LIPA < SB. 10-yr risk for a first ASCVD event was estimated using the pooled cohort equations.ResultsAfter adjusting for age, gender, race–ethnicity and obesity, Group 2 (β = − 0.28; p = 0.44) was not significantly different than Group 1, but Groups 3 (β = 1.09; p = 0.01) and 4 (β = 1.44; p < 0.001) had a higher pooled risk score.ConclusionsThose in the least desirable movement pattern (Group 4) had the highest pooled risk score. Given the similar risk scores for Groups 1 and 2, future research is needed to determine if sufficient MVPA can counteract the potential consequences associated with an imbalanced LIPA:SB ratio (i.e., LIPA < SB).     

Prospective COVID-19 related changes in physical activity and sedentary time and associations with symptoms of depression and anxiety

ProblemThe COVID-19 pandemic is associated with psychological distress. Decreased moderate-vigorous physical activity (MVPA) and increased sedentary time may be exacerbating pandemic-related symptoms of anxiety and depression, but existing studies exploring these associations are almost entirely cross-sectional.MethodsReported data from 2018 and Summer 2020 were used to create change categories based on compliance with MVPA guidelines and relative sedentary time. Participants completed the Patient Health Questionnaire-4 (PHQ-4) in Summer 2020. Associations among changes in MVPA and sedentary time (separately and jointly) with psychological distress (total PHQ-4 score) were examined with ordinal logistic regression and associations with depressive or anxiety symptoms were examined with logistic regression.ResultsAmong 2,240 participants (65% women, mean age 57.5 years), 67% increased sedentary time and 21% became inactive between the two time points. After multivariate adjustment, participants who became (OR = 1.71, 95% CI: 1.05–2.78) or remained inactive (OR = 2.07, 1.34–3.22) were more likely to experience depressive symptoms compared to those who remained active. Participants who increased sedentary time were also more likely to experience depressive symptoms compared to those who maintained sedentary time (OR = 1.78, 1.13–2.81). Jointly, those who increased sedentary time while remaining (OR = 3.67, 1.83–7.38) or becoming inactive (OR = 3.02, 1.44–6.34) were much more likely to have depressive symptoms compared to the joint referent (remained active/maintained sedentary time). Associations with anxiety symptoms were not statistically significant.ConclusionsThese findings support the value of promoting MVPA and limiting sedentary time during stressful events associated with psychological distress, like the COVID-19 pandemic.     

Abdominal obesity as a mediator of the influence of physical activity on insulin resistance in Spanish adults

ObjectiveThe aim of the study was to analyze the relationship between moderate-to-vigorous physical activity (MVPA) and insulin resistance (IR) in Spanish adults and to examine whether this relationship is mediated by abdominal obesity (waist circumference — WC).MethodsThe cross-sectional study included 1162 healthy subjects belonging to the EVIDENT study (mean age 55.0 ± 13.3 years; 61.8% women) from six different Spanish provinces. Moderate-to-vigorous physical activity (MVPA) was measured objectively over 7 days using Actigraph accelerometers, collecting data in 60-second epochs, and retaining respondents with ≥ 4 valid days for the analysis. The homeostasis model of assessment (HOMA-IR) was used to determine IR, and its individual components – fasting glucose and insulin – were determined using standard protocols. Linear regression models were fitted according to Baron and Kenny's procedures for mediation analysis.ResultsFasting insulin and HOMA-IR levels were significantly worse in adults who spent fewer minutes in MVPA (first quartile ≤ 30.1 and 22.7 min/day in men and women, respectively) after adjusting for age, sex, smoking habits, drinking habits, accelerometer wear time, sedentary time, and Mediterranean diet adherence. However, when WC was added to the ANCOVA models as a covariate, the effects disappeared. Mediation analysis reported that WC acts as a full mediator in the relationship between MVPA and IR (HOMA-IR and fasting insulin).ConclusionThese findings show that WC plays a pivotal role in the relationship between MVPA and IR, and therefore highlights that decreasing abdominal obesity might be considered as an intermediate outcome for evaluating interventions aimed at preventing diabetes mellitus.     

Sit less,stand more: A randomized point-of-decision prompt intervention to reduce sedentary time

ObjectiveTo determine if a point-of-decision prompt (PODP) targeting sedentary behaviour influenced the proportion of standing individuals during presentations at an academic conference.MethodsTwelve, one-hour groups of presentation sessions (Global Summit on the Physical Activity of Children conference, May 2014) were included in this study; half were randomly assigned to the intervention group and half to the control group. The intervention group was exposed to an oral PODP at the beginning and middle of the presentations. Researchers performed three counts: beginning (e.g. first 10 min), middle (e.g. 30–40 min), and end (e.g. 50–60 min); each count included the number of individuals in the audience and the number of standing individuals.ResultsA significantly larger proportion of individuals chose to stand during intervention group presentations (16.9 ± 2.0%) compared to control group presentations (10.5 ± 1.5%; chi² = 7.13; p < 0.05).ConclusionsThis study demonstrated the effectiveness of PODPs at decreasing sedentary behaviour during an academic conference. PODPs are simple, cost-effective interventions that require minimal time commitment, and represent a population health intervention that could reduce sedentary behaviour in a large group setting.