Higher levels of objectively measured sedentary behavior is associated with worse cognitive ability: Two-year follow-up study in community-dwelling older adults Definition, measurement, and health risks associated with sedentary behavior. Sedentary behavior & health-related quality of life among congestive heart failure patients. Intervening to Reduce Sedentary Behaviors and Childhood Obesity among School-Age Youth: A Systematic Review of Randomized Trials A systematic review of school-based interventions targeting physical activity and sedentary behaviour among older adolescents Feasibility and preliminary efficacy of an intervention to reduce older adults’ sedentary behavior Sedentary behavior and psychiatric symptoms in overweight and obese adults with schizophrenia and schizoaffective disorders (WAIST Study) Is Objectively Assessed Sedentary Behavior, Physical Activity and Cardiorespiratory Fitness Linked to Brain Plasticity Outcomes in Old Age? Comparison of Actical and activPAL measures of sedentary behaviour in preschool children. Objectively assessed physical activity and lower limb function and prospective associations with mortality and newly diagnosed disease in UK older adults: an OPAL four-year follow-up study Reducing Sedentary Behavior Versus Increasing Moderate-to-Vigorous Intensity Physical Activity in Older Adults Correlates of preschool children’s objectively measured physical activity and sedentary behavior: a cross-sectional analysis of the SPLASHY study Fear-avoidance Beliefs, Physical Activity, and Disability in Elderly Individuals With Chronic Low Back Pain and Healthy Controls Mobility difficulties and physical activity as predictors of mortality and loss of independence in the community-living older population. Objectively measured physical activity and sedentary behavior and quality of life indicators in survivors of breast cancer Patterns of Sedentary Behavior and Mortality in U.S. Middle-Aged and Older Adults Physical activity and sedentary behavior in relation to lung cancer incidence and mortality in older women: The Women's Health Initiative.
Background : A number of cross‐sectional studies have suggested that higher levels of  sedentary behavior ( SB ) are associated with worse cognitive abilities  in older age . There is a paucity of longitudinal studies investigating this relationship utilizing objective ly assessed SB . This study investigated the relationship between objective ly assessed SB and future cognitive abilities in a cohort of older adults . Methods : A longitudinal study over 22.12 ± 1.46 months including 285 community‐dwelling older adults across 14 regions in Taiwan was undertaken . Cognitive ability was ascertained using a Chinese version of the Ascertain Dementia 8‐item Question naire ( AD8 ) and SB captured by 7 days accelerometer data . Multivariable negative binomial regression models adjusted for confounders were undertaken . Results : 274 community‐dwelling older adults finished the study ( age = 74.6 ± 6.2 , % female = 54.4 % ) . At baseline , 20.1 % ( n = 55 ) , 48.5 % ( n = 133 ) and 31.4 % ( n = 86 ) of the sample engaged in high ( 11 + h ) , medium ( 7–10.99 h ) and low ( < 7 h ) of SB respectively . In the fully adjusted model , higher levels of SB were associated with an increased risk of worse cognitive ability at follow up ( adjusted rate ratio (ARR)1.09 ( 95%CI:1.00–1.19 ) ) , with the strongest relationship evident in those engaging in over 11 h of SB ( ARR 2.27 ( 95%CI:1.24–4.16 ) ) . The relationship remained evident after adjusting for depressive symptoms and physical activity . Conclusion : Our data suggests that objective ly assessed SB , particularly when over 11 h a day , is independently associated with worse cognitive ability over a two year period . Our data adds to the pressing reasons to reduced SB in older age . HighlightsFirst prospect i ve study to investigate objective  ly sedentary behavior ( SB ) and cognition in older adults . Higher levels of objective SB were independently associated with worse cognitive ability over two years . This relationship was most pronounced in older people spending over 11 h a day being sedentary PURPOSE AND METHODS Although evidence is accumulating that sedentary behavior ( SB ) , independent of moderate-to-vigorous intensity physical activity ( MVPA ) , is associated with cardiometabolic and aging outcomes in adults , several gaps present opportunities for future research . This article reports on the " Research Evidence on Sedentary Behavior " session of the Sedentary Behavior : Identifying Research Priorities workshop , sponsored by the National Heart , Lung , and Blood Institute and the National Institute on Aging , which aim ed to identify priorities in SB research . RESULTS AND CONCLUSIONS A consensus definition of SB has not yet been established , although agreement exists that SB is not simply all behaviors other than MVPA . The two most common definitions are as follows : one based solely on intensity ( < 1.5 metabolic equivalents [ METs ] ) and another which combines low intensity ( ≤1.5 METs ) with a seated or reclining posture . Thus , for the definition of SB , evaluation of whether or not to include a postural component is a research priority . SB assessment method ologies include self-report and objective measurement , each offering distinct information . Therefore , evaluation , st and ardization , and comparison across self-report and objective assessment methods are needed . Specific priorities include the development and validation of novel devices capable of assessing posture and st and ardization of research practice s for SB assessment by accelerometry . The prospect i ve evidence that SB relates to health outcomes is limited in that SB is almost exclusively measured by self-report . The lack of longitudinal studies with objective ly measured SB was recognized as a major research gap , making examination of the association between objective ly measured SB and adverse health outcomes in longitudinal studies a research priority . Specifically , studies with repeated measures of SB , evaluating dose-response relationships , with inclusion of more diverse population s are needed BACKGROUND Previous research demonstrates that participation in light-intensity physical activity ( LIPA ) and moderate-to-vigorous physical activity ( MVPA ) are favorably associated with health-related quality of life ( HRQOL ) . Emerging work demonstrates that  sedentary behavior  ( SB ) is detrimentally associated with various cardiometabolic biomarkers , with few studies exploring the association of SB on HRQOL , and no studies examining this among congestive heart failure patients . Therefore , the purpose of this study was to examine the potential independent associations of SB on HRQOL among congestive heart failure patients . METHODS Data from the 2003 - 2006 National Health and Nutrition Examination Survey were used .  Physical activity was assessed over 7days during all waking hours using the ActiGraph 7164 accelerometer .  HRQOL was assessed using the Centers for Disease Control HRQOL index survey . RESULTS 190 participants self-reported a physician-diagnosis of congestive heart failure . After adjustments , SB behavior ( 1-min/day increase ) was associated with worse HRQOL ( β=0.004 ; 95 % CI : 0.0004 - 0.007 ; P=0.03 ) . When MVPA was added as a covariate to this model , SB remained significantly associated with worse HRQOL ( β=0.003 ; 95 % CI : 0.0001 - 0.007 ; P=0.04 ) . However , when adding LIPA to this model that also included MVPA as a covariate , SB was no longer associated with HRQOL ( β=0.0001 ; 95 % CI : -0.003 - 0.004 ; P=0.92 ) . CONCLUSIONS If confirmed by prospect ive/experimental work , this suggests that SB may not have detrimental HRQOL effects among congestive heart failure patients Objective . To assess the effectiveness of interventions that focus on reducing  sedentary behavior ( SB ) among school-age youth and to identify elements associated with interventions ' potential for translation into practice setting s. Methods . A comprehensive literature search was conducted using 4 data bases for peer- review ed studies published between 1980 and April 2011 . R and omized trials , which lasted at least 12 weeks , aim ed at decreasing  SB among children aged 6 to 19 years were identified . Results . Twelve studies were included ; 3 focused only on SB , 1 focused on  physical activity ( PA )  , 6 were combined SB and PA interventions , and 2 studies targeted SB , PA , and diet .  The majority of the studies were conducted in a school setting , while others were conducted in such setting s as clinics , community centers , and libraries . Conclusions . Overall , interventions that focused on decreasing SB were associated with reduction in time spent on SB and /or improvements in anthropometric measurements related to childhood obesity . Several of the studies did consider elements related to the intervention 's potential for translation into practice setting ABSTRACT Lack of  physical activity  (  PA  ) and high levels of sedentary behaviour ( SB ) have been associated with health problems . This systematic review evaluates the effectiveness of school-based interventions to increase PA  and decrease SB  among 15–19-year-old adolescents , and examines whether intervention characteristics ( intervention length , delivery mode and intervention provider ) and intervention content ( i.e. behaviour change techniques , BCTs ) are related to intervention effectiveness . A systematic search of r and omised or cluster r and omised controlled trials with outcome measures of PA and /or SB rendered 10 results . Risk of bias was assessed using the Cochrane risk of bias tool . Intervention content was coded using Behaviour Change Technique Taxonomy v1 . Seven out of 10 studies reported significant increases in PA . Effects were generally small and short-term ( Cohen 's d ranged from 0.132 to 0.659 ) . Two out of four studies that measured SB reported significant reductions in SB . Interventions that increased PA  included a higher number of BCTs , specific BCTs ( e.g. , goal setting , action planning and self-monitoring ) , and were delivered by research staff . Intervention length and mode of delivery were unrelated to effectiveness . More studies are needed that evaluate long-term intervention effectiveness and target SBs among older adolescents Older adults represent the segment of the population that sits the most . This study evaluated the feasibility , acceptability , safety , and preliminary efficacy of an intervention to reduce sedentary behavior ( SB ) in older adults that can be disseminated broadly for limited cost and delivered by paraprofessionals with limited training . Senior centers in Central Pennsylvania were r and omized to receive one of two healthy aging programs ( i.e. , intervention or comparison ) . Participants in both groups attended three 90-min meetings over 2 weeks . Behavior change content was delivered at the second session ( i.e. , day 7 ) . Forty-two participants ( nintervention = 25 , ncomparison = 17 ) were recruited from five senior centers . Content for the intervention group focused on  reducing SB while comparison group content focused on reducing social isolation  . Self-reported SB was assessed on days 7 and 14 . Repeated- measures ANOVA revealed a significant group × time interaction for total and weekday , but not weekend , SB . In the week following the delivery of group content , participants in the intervention group reported an average decrease in total SB of 837.8 min/week ; however , the comparison group reported a nonsignificant average decrease of 263.0 min/week of total SB . Participants in the intervention group also reported an average decrease in weekday SB of 132.6 min/weekday ( d = −0.83 ) in the week following the delivery of group content ; however , the comparison group reported a nonsignificant decrease of 24.0 min/weekday ( d = −0.16 ) . There were no significant changes in weekend SB in either group in the week following the delivery of group content . Participants ’ attendance , measurement completion , and program ratings were high . Safety issues were minimal . This intervention was feasible to implement and evaluate , acceptable to older adults , and showed promise for reducing older adults ’ SB OBJECTIVE Examine the association between sedentary behavior and psychiatric symptoms among overweight and obese adults with schizophrenia or schizoaffective disorders ( SZO/SA ) . DESIGN R and omized clinical trial ; Weight Assessment and Intervention in Schizophrenia Treatment ( WAIST ) Study : baseline data collected 2005 - 2008 . SETTING University of Pittsburgh Medical Center , Pittsburgh , PA , USA . PARTICIPANTS Community-dwelling adults diagnosed with SZO/SA , with mild symptom severity [ Positive and Negative Syndrome Scale (PANSS)<90 ] , who were interested in losing weight , age 18 - 70years , BMI > 27kg/m(2 ) . MEASUREMENTS Objective ly measured  sedentary behavior by accelerometry , and  psychopathology  assessed by PANSS . Participants wore the actigraphs for 7 consecutive days during their waking hours . Sedentary behavior was defined as ≤100 counts per minute during wear-time and excluded sleep and non-wear time . RESULTS On average , 81 % of the participant 's monitoring time or 756min/day was classified as sedentary behavior using accelerometry . No association was observed between sedentary behaviors and PANSS psychiatric symptoms [ total ( p≥0.75 ) , positive ( p≥0.81 ) , negative ( p≥0.59 ) and general psychopathology ( p≥0.65 ) subscales ] . No association was observed between sedentary behaviors and age , race , gender and BMI . CONCLUSION From a clinical and public health perspective , the amount of time ( approximately 13h ) and percentage of time ( 81 % excluding non-wear time associated with sleeping ) engaged in sedentary behavior among overweight and obese adults in this population is alarming , and points to an urgent need for interventions to decrease sedentary behaviors . The lack of associations between sedentary behavior and psychiatric symptoms may be due to a ceiling effect for sedentary behavior The aim of this cross-sectional study was to determine the associations of objective ly assessed habitual physical activity and physical performance with brain plasticity outcomes and brain-derived neurotrophic factor ( BDNF ) levels in cognitively healthy older adults . Physical performance was analyzed based on cardiopulmonary exercise-testing data and accelerometer-based physical activity was analyzed as total activity counts , sedentary time , light physical activity and moderate to vigorous physical activity . Brain plasticity outcomes included magnetic resonance spectroscopy (MRS)-based markers , quantitative imaging-based hippocampal volume and BDNF serum levels . The association between physical performance and hippocampal volume was strongly influenced by participants ' education , sex , age and BMI . Confounder-controlled correlation revealed significant associations of brain plasticity outcomes with physical activity but not with performance . MRS-based adenosine triphosphate to phosphocreatine and glycerophosphocholine to phosphocreatine ratios were significantly associated with accelerometer total activity counts . BDNF was detrimentally associated with sedentary time but beneficially related to  accelerometer total activity  counts and moderate to vigorous physical activity . Exceeding the current moderate to vigorous physical activity recommendations led to significantly higher BDNF levels . Our results indicate that regular physical activity might be beneficial for preserving brain plasticity in higher age . In this study these associations were not mediated significantly by physical performance . Overall physical activity and exceeding current moderate to vigorous physical activity recommendations were positively associated with BDNF . Sedentary behavior , however , seems to be negatively related to neurotrophic factor bioavailability in the elderly OBJECTIVES The purpose of this study was to examine the convergent validity of the Actical and activPAL to measure  sedentary behaviour ( SB ) and non-SB in preschoolers in a free-living environment . DESIGN A convenience sample of 49 preschoolers ( 22 boys ; 4.0 ± 0.5 years ) from six early childhood centres in Auckl and , New Zeal and were included in data analysis . METHODS Participants wore a hip-mounted Actical and a thigh-mounted activPAL accelerometer simultaneously during centre attendance for one day and data were collected in 15s epochs . Bl and -Altman tests were used to assess differences in group mean minutes and percentage of time in (non-)SB between both monitors . Agreement between binary coded ( SB vs. non-SB ) 15s-by-15s Actical and activPAL data was evaluated by calculating percentage agreement and κ statistic . RESULTS The monitors were worn on average for 294.8 ± 46.3 min result ing in a total of 57,780 15s epochs . Bl and -Altman tests suggested a small group mean difference in (non-)SB ( 1.3 min ; 0.1 % ) and a wide prediction interval ( 121.3 min ; 39.2 % ) . No obvious systematic bias was observed in the Bl and -Altman plot . Percentage agreement between the 15s-by-15s Actical and activPAL data of all participants was 73.0 % ( inter-child range : 36.8 - 93.8 % ) . The κ statistic showed moderate agreement with a value of 0.46 ( 95 % CI : 0.45 - 0.47 ) . CONCLUSIONS Although the group mean estimate of (non-)SB was similar between the Actical and activPAL , the output of both monitors can not be considered convergent as meaningful r and om disagreement was found between both monitors Background : objective measures of physical activity and function with a diverse cohort of UK adults in their 70s and 80s were used to investigate relative risk of all-cause mortality and diagnoses of new diseases over a 4-year period . Participants : two hundred and forty older adults were r and omly recruited from 12 general practice s in urban and suburban areas of a city in the United Kingdom . Follow-up included 213 of the baseline sample . Methods : socio-demographic variables , height and weight , and self-reported diagnosed diseases were recorded at baseline . Seven-day accelerometry was used to assess total physical activity , moderate-to-vigorous activity and sedentary time . A log recorded trips from home .  Lower limb function was assessed using the Short Physical Performance Battery . Medical records were accessed on average 50 months post baseline , when new diseases and deaths were recorded . Analyses : ANOVAs were used to assess socio-demographic , physical activity and lower limb function group differences in diseases at baseline and new diseases during follow-up . Regression models were constructed to assess the prospect i ve associations between physical activity and function with mortality and new disease . Results : for every 1,000 steps walked per day , the risk of mortality was 36 % lower ( hazard ratios 0.64 , 95 % confidence interval ( CI ) 0.44–0.91 , P = 0.013 ) . Low levels of moderate-to-vigorous physical activity ( incident rate ratio ( IRR ) 1.67 , 95 % CI 1.04–2.68 , P = 0.030 ) and low frequency of trips from home ( IRR 1.41 , 95 % CI 0.98–2.05 , P = 0.045 ) were associated with diagnoses of more new diseases . Conclusion : physical activity should be supported for adults in their 70s and 80s , as it is associated with reduced risk of mortality and new disease development Objective : To compare the effects of behavioral interventions targeting decreased sedentary behavior versus increased moderate-to-vigorous intensity physical activity ( MVPA ) in older adults . Method : Inactive older adults ( N = 38 , 68 ± 7 years old , 71 % female ) were r and omized to 12-week interventions targeting decreased sedentary behavior ( Sit Less ) or increased MVPA ( Get Active ) . The SenseWear armb and was used to objective ly assess activity in real time . Assessment s included a blinded armb and , the Community Health Activites Model Program for Senior ( CHAMPS ) question naire , 400-meter walk , and the Short Physical Performance Battery ( SPPB ) . Results : Objective ly measured MVPA increased in Get Active ( 75 ± 22 min/week , p < .001 ) ; self-reported MVPA increased in both groups ( p < .05 ) . Sedentary behavior did not change in either group ( all p > .05 ) . Only the Sit Less group improved the SPPB score ( 0.5 ± 0.3 , p = .046 ) . Discussion : Targeting reduced sedentary behavior had a greater effect on physical function among inactive but high functioning older adults over 12 weeks . Future studies of longer duration and combining increased MVPA with reduced sedentary behavior are needed Background Identifying ways to promote physical activity and decrease sedentary time during childhood is a key public health issue . Research on the putative influences on preschool children ’s  physical activity ( PA ) and  sedentary behavior  ( SB ) is limited and has yielded inconsistent results . Our aim was to identify correlates of PA and SB in preschool children . Methods Cross-sectional data were drawn from the Swiss Preschoolers ’ Health Study ( SPLASHY ) , a Swiss population -based cohort study . Of 476 two to six year old children , 394 ( 54 % boys ) had valid PA data assessed by accelerometry .  Information on exposure data was directly measured or extracted from parental question naires . Multilevel linear regression modeling was used to separately assess associations between 35 potential correlates and  total PA ( TPA ) , moderate-to-vigorous PA ( MVPA ) and SB . Results In total , 12 correlates from different domains were identified . TPA and MVPA were greater in boys than girls , increased with age and were positively associated with gross motor skills . Children from single parent families had a higher level of TPA and spent less time sedentary than those living with two parents . Time spent outdoors was positively associated with TPA and negatively with SB . The child ’s activity temperament was related all three outcomes , whereas parental sports club membership , living area per person and neighborhood safety were associated with SB only . Fixed and r and om factors in the final models accounted for 28 % , 32 % and 22 % of the total variance in TPA , MVPA and SB , respectively . Variance decomposition revealed that age , sex and activity temperament were the most influential correlates of both , TPA and MVPA , whereas the child ’s activity temperament , time outdoors and neighborhood safety were identified as the most important correlates of SB . Conclusions A multidimensional set of correlates of young children ’s  activity behavior has been identified . Personal factors had the greatest influence on PA , whereas environmental-level factors had the greatest influence on SB . Moreover , we identified a number of previously unreported , potentially modifiable correlates of young children ’s PA and SB . These factors could serve to define target groups or become valuable targets for change in future interventions .Trial registration Current Controlled Trials IS RCT N41045021 ( date of registration : 21.03.14 ) Objective Research studies focussing on the fear-avoidance beliefs model ( FABM ) have exp and ed considerably during the last years , however , there has been very little research directed at the elderly . The objective of the present study was to investigate the validity of the FABM in older patients with chronic low back pain ( CLBP ) . Method In a cross-sectional study , a group of elderly patients with CLBP ( N=103 ) was compared with an age-matched group of pain-free individuals ( N=59 ) to test the constructs inherent in the FABM . Constructs include  fear avoidance beliefs ( FABs ) , disability , disuse , and physical activity . In addition , the relationship of these constructs was also investigated in the patient group . CLBP- patients had an average age of 71.41 years ( SD=5.2 ) and pain-free individuals of 71.19 years ( SD=4.73 ) . Individuals participated in a photographed series of physical activities adapted to the age group ( Photograph Series of Daily Activities-German version for the elderly ) for the assessment of FAB , in the Hannover Disability Question naire , in the Freiburg Physical Activity Question naire , and in an ultrasound measurement to evaluate lumbar flexion . In addition , they completed an activity diary for 1 week . Before computation , the physical activity measurements were converted into metabolic units that characterize energy expenditure . Results In the patient group , FAB , pain intensity , and age predicted functional capacity , but not physical activity . Lumbar flexion was predicted by FAB and age . Patients were more fear-avoidant , reported more disability , and displayed less lumbar flexion than the pain-free individuals . No differences between the groups could be detected in regard to energy expenditure measured either by the question naire or by diary data . Conclusions The findings are consistent with results reported in the literature for younger age groups and confirm the assumption that the FABM is also valid for the elderly OBJECTIVE In older people , mobility impairments and physical inactivity are risk factors for further disability and death . We studied the interaction of physical activity and mobility impairment as a predictor of dependence and mortality . DESIGN A population -based , prospect i ve study . The data were collected in structured interviews in the year 1988 and 8 years later in the year 1996 as part of the Evergreen Project . PARTICIPANTS Subjects were 1109 independently living , at baseline 65- to 84-year-old people in the city of Jyvaskyla , in central Finl and . METHODS Participants were ranked into four groups : ( 1 ) Intact mobility and physically active ( Mobile-Active ) , ( 2 ) Intact mobility and sedentary ( Mobile-Sedentary ) , ( 3 ) Impaired mobility and physically active ( Impaired-Active ) , and ( 4 ) Impaired mobility and sedentary ( Impaired-Sedentary ) . The confounders adjusted for in the models included age , marital status , education , chronic conditions , smoking , and physical exercise earlier in life . RESULTS In men and women , the relative risk of death was two times greater in Impaired-Active and three times greater in Impaired-Sedentary groups than the risk of death in Mobile-Active groups . However , the risk of death did not differ between Mobile-Active and Mobile-Sedentary groups . The odds ratio for dependency ( 95 % confidence interval ) in Impaired-Sedentary men was 5.21 ( 1.44 - 18.70 ) and in Impaired-Sedentary women was 2.92 ( 1.52 - 5.60 ) compared to Mobile-Active groups . The risk of dependence did not differ significantly between Mobile-Active , Mobile-Sedentary , and Impaired-Active groups . CONCLUSIONS Mobility impairments predicted mortality and dependence . However , among people with impaired mobility , physical activity was associated with lower risks , whereas the risk did not differ according to activity level among those with intact mobility . Despite of their overall greater risk , mobility-impaired people may be able to prevent further disability and mortality by physical exercise The primary purpose of the current study was to determine prospect i ve associations of accelerometer‐assessed physical activity intensity and sedentary time with health‐related quality of life ( HRQOL ) indicators among survivors of breast cancer Adults are sedentary for an alarming 9 to 10 hours per day ( 1 ) . Accordingly , the popular press has coined the phrase sitting is the new smoking to describe a current epidemic of developed nations ( 24 ) . Evidence indicates that sedentary time is associated with incident cardiovascular disease , incidence of cardiovascular diseaserelated risk factors , and mortality ( 5 , 6 ) . Of note , the risk conferred by prolonged sedentariness is eliminated only by high levels of moderate- to vigorous-intensity physical activity ( MVPA ) ( about 60 to 75 min/d ) , which exceed physical activity recommendations ( 7 , 8) . As such , sedentary behavior is now believed to represent a clinical ly important aspect of a person 's physical activity profile and is no longer considered simply the extreme low end of the physical activity continuum ( 5 ) . Studies linking sedentary behavior to health outcomes have relied almost exclusively on self-reported  sedentary time  , which is subject to reporting bias and measurement error ( 9 ) . A 2015 systematic review ( 5 ) identified only 1 study ( NHANES [ National Health and Nutrition Examination Survey ] ) that examined the association between objective ly measured sedentary time and health outcomes , a study limited by a small event rate ( 10 ) . New studies using NHANES data have since been published , with longer follow-up and higher event rates ( 1115 ) . However , some of these studies have reported an association between objective ly measured sedentary time and mortality ( 11 , 14 , 15 ) , but others have not ( 12 , 13 ) . Additional cohort studies are thus needed to rectify evidence gaps . Furthermore , studies using accelerometers to objective ly measure sedentary behavior conventionally operationalize sedentary time as the total number of sedentary minutes per day . This approach ignores patterns of accumulated sedentary behavior over time . For example , accumulation of sedentary time in a few long bouts or many short bouts represents 2 distinct patterns of sedentary time accrual . Experimental studies have shown that acute periods of prolonged , uninterrupted sedentary behavior cause greater detrimental cardiometabolic effects than sedentary behavior that is periodically interrupted ( 1618 ) , suggestive that it is not just total sedentary time that is relevant to health outcomes , but also the manner in which it is accumulated . Few longitudinal studies , however , have explored the association between prolonged , uninterrupted sedentary behavior and mortality to corroborate these findings . To inform guidelines on reducing sedentary behavior ( target reductions in overall sedentary time or target interruption of prolonged sedentary bouts ) , evidence from prospect i ve studies is needed to 1 ) confirm the association between total sedentary time and mortality using objective measures , 2 ) determine whether prolonged sedentary bouts confer risk for death , and 3 ) eluci date whether the total volume of sedentary time and its pattern of accumulation individually or jointly contribute to risk for death . The purpose of this study , therefore , was to examine the association between objective ly measured sedentary time ( both total volume and accrual in prolonged bouts ) and all-cause mortality in a national cohort of U.S. middle-aged and older adults enrolled in the REGARDS ( Reasons for Geographic and Racial Differences in Stroke ) study . Methods Study Population REGARDS is a population -based study design ed to examine racial and regional disparities in stroke . It comprises 30239 white and black adults aged 45 years or older enrolled between 2003 and 2007 from across the contiguous United States ( 19 , 20 ) . Detailed design and methods for REGARDS are described elsewhere ( 21 ) . Briefly , demographic and cardiovascular risk factor data were collected by telephone interview and an in-home physical assessment on enrollment . A detailed summary of baseline measures is provided in the Supplement . Participants ( or their proxies ) were then followed for 6-month intervals to ascertain vital status . Objective measurements of sedentary behavior were collected from active REGARDS participants from 2009 to 2013 ( mean time from study enrollment , 5.7 years [ SD , 1.5 ] ; range , 1.9 to 9.5 years ) ( 22 ) . A total of 7985 participants adhered to accelerometer wear requirements ( 4 days with accelerometer wear 10 hours ) , provided follow-up data , and were available for the current analyses ( Supplement Figure 1 ) . Supplement Table 1 shows the characteristics of included versus excluded REGARDS participants . The REGARDS study protocol was approved by the institutional review boards of participating institutions . All participants provided informed consent . Supplement . Supplementary Material Accelerometer Data Collection Methods for accelerometer data collection are described elsewhere ( 22 ) . Briefly , participants were fitted with an Actical ( Philips Respironics ) accelerometer secured to their right hip using a nylon belt and were instructed to wear the device during waking hours for 7 consecutive days . The Actical had been vali date d formeasurement of physical activity and sedentary behavior and was shown to have acceptable reliability ( 2325 ) . Activity counts were summed over 1-minute epochs . Nonwear periods were defined as at least 150 consecutive minutes of 0 activity counts . This nonwear algorithm was previously vali date d against daily log sheets in REGARDS participants ( 26 ) . Measurements of 0 to 49 , 50 to 1064 , and at least 1065 counts per minute were defined as sedentary behavior , light-intensity physical activity , and MVPA , respectively , as determined in a laboratory-based calibration study ( 27 ) . A sedentary bout was defined as consecutive minutes in which the accelerometer registered fewer than 50 counts per minute . A sedentary break was defined as at least 1 minute in which 50 or more counts per minute were registered after a sedentary bout . Both sedentary bouts and breaks were exclusively continuous periods , with no interruptions or nonwear intervals allowed in the definition . Outcome Ascertainment All-cause mortality was the primary outcome , defined as any death after completion of the accelerometer protocol regardless of cause . Date s of death were confirmed through review of death certificates , medical records , and administrative data bases . Deaths through 4 September 2015 were included in the current analysis . Statistical Analysis Sedentary and physical activity variables were averaged across compliant days ( 10 hours of wear ) . Because of a high correlation between total sedentary time and wear time ( Supplement Figure 2 ) , we corrected for the influence of wear time by st and ardizing total sedentary time to 16 hours of wear time per day using the residuals obtained when regressing total sedentary time on wear time ( see Methods section of the Supplement ) ( 2830 ) . Participants were stratified into quartiles according to total sedentary time and , separately , mean sedentary bout duration ( a measure of overall prolonged , uninterrupted sedentary behavior ) . Cox proportional hazards regression modeling was used to calculate the hazard ratio ( HR ) for all-cause mortality associated with quartiles of total sedentary time ( and separately , mean sedentary bout length ) . Crude HRs were initially calculated . Subsequent HRs were calculated after adjustment for age , race , sex , region of residence , education , and season the accelerometer was worn ( model 1 ) , with further adjustment for current smoking , alcohol use , body mass index ( BMI ) , diabetes , hypertension , dyslipidemia , estimated glomerular filtration rate less than 60 mL/min/1.73 m2 , atrial fibrillation , history of coronary heart disease , and history of stroke ( model 2 ) . Models were additionally adjusted for MVPA expressed continuously ( model 3 ) . Tests for linear trend across quartiles were conducted by including the quartile for each participant as an ordinal variable in regression models . Proportional hazards assumptions were confirmed with a Kolmogorov-type supremum test ( 31 ) . The above analyses were then repeated in a fully adjusted model , testing interactions for age ( < 65 and 65 years ) , sex ( male and female ) , race ( black and white ) , BMI category ( normal weight and overweight or obese ) , and MVPA category ( < 150 min/wk and 150 min/wk ) . As a secondary analysis , we examined the continuous doseresponse relationship between each sedentary characteristic and all-cause mortality in a fully adjusted model ( model 3 ) using restricted cubic splines ( 32 ) . Cubic polynomials were fitted with the mean of each sedentary characteristic set as the reference and knots placed at the 5th , 35th , 65th , and 95th percentiles ( 33 ) . Nonlinear associations were evaluated using the likelihood ratio test . For nonlinear associations , spline models were used to describe the associations and when the association was determined to be linear , a linear model was used . Because of multicollinearity between total sedentary time and mean sedentary bout duration ( r= 0.61 ) , both variables were not included in the same model . Alternatively , to examine the individual and joint associations of total sedentary time and prolonged , uninterrupted sedentary behavior with mortality , participants were classified into 4 categories : low total sedentary time ( < 750 min/d ) and low prolonged sedentary bout time ( < 10 min/bout ) , low total sedentary time  and high prolonged sedentary bout time  ( 10 min/bout ) , high total sedentary time  ( 750 min/d ) and low prolonged sedentary bout time , and high total sedentary time and high prolonged sedentary bout time . Hazard ratios for all-cause mortality were calculated for each joint category in comparison with the lowlow group in a fully adjusted model ( model 3 ) . Thresholds for total sedentary time ( 750 min/d ) and mean sedentary bout duration ( 10 min/bout ) were selected on the basis of the restricted cubic splines and were confirmed using a method described by Contal and O'Quigley ( see Methods section of the Supplement ) ( 34 ) . To allow for the possibility that sedentary bouts Physical activity has been associated with lower  lung cancer incidence and mortality  in several population s. We investigated these relationships in the Women 's Health Initiative Observational Study ( WHI-OS ) and Clinical Trial ( WHI-CT ) prospect i ve cohort of postmenopausal women . The WHI study enrolled 161,808 women aged 50 - 79 years between 1993 and 1998 at 40 U.S. clinical centers ; 129,401 were eligible for these analyses . Cox proportional hazards models were used to assess the association of baseline  physical activity levels [ metabolic equivalent (MET)-min/week : none < 100 ( reference ) , low 100 to < 500 , medium 500 to < 1,200 , high 1,200 + ] and sedentary behavior with total lung cancer incidence and mortality . Over 11.8 mean follow-up years , 2,148 incident lung cancer cases and 1,365 lung cancer deaths were identified . Compared with no activity , higher physical activity levels at study entry were associated with lower lung cancer incidence [ p = 0.009 ; hazard ratios ( 95 % confidence intervals ) for each physical activity category : low , HR : 0.86 ( 0.76 - 0.96 ) ; medium , HR : 0.82 ( 0.73 - 0.93 ) ; and high , HR : 0.90 ( 0.79 - 1.03 ) ] , and mortality [ p < 0.0001 ; low , HR : 0.80 ( 0.69 - 0.92 ) ; medium , HR : 0.68 ( 0.59 - 0.80 ) ; and high , HR : 0.78 ( 0.66 - 0.93 ) ] . Body mass index ( BMI ) modified the association with lung cancer incidence ( p = 0.01 ) , with a stronger association in women with BMI < 30 kg/m(2 ) . Significant associations with sedentary behavior were not observed . In analyses by lung cancer subtype , higher total physical activity levels were associated with lower lung cancer mortality for both overall NSCLC and adenocarcinoma . In conclusion , physical activity may be protective for  lung cancer incidence and mortality in postmenopausal women , particularly in non-obese women
R and omized controlled trials found a positive correlation for SB with BMI , neck circumference , fat mass , HbA1C , cholesterol and insulin levels , cohort studies additionally for WC , leptin , C-peptide , ApoA1 and Low density lipoprotein and a negative correlation for HDL .
Most studied biomarkers associated with SB were of cardiovascular or metabolic origin .
OBJECTIVE Pathomechanisms of sedentary behaviour ( SB ) are unclear .
We conducted a systematic review to investigate the associations between SB and various biomarkers in older adults .