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. Quantification of Outdoor Mobility by Use of Accelerometer-Measured Physical Behaviour Comparison of Actical and activPAL measures of sedentary behaviour in preschool children. Feasibility and preliminary efficacy of an intervention to reduce older adults’ sedentary behavior Reducing Sedentary Behavior Versus Increasing Moderate-to-Vigorous Intensity Physical Activity in Older Adults A cluster-randomized controlled trial to reduce sedentary behavior and promote physical activity and health of 8-9 year olds: The Transform-Us! Study Toward Automated, At-Home Assessment of Mobility Among Patients With Parkinson Disease, Using a Body-Worn Accelerometer Accelerometer-measured sedentary time and physical activity-A 15 year follow-up of mortality in a Swedish population-based cohort. Correlates of preschool children’s objectively measured physical activity and sedentary behavior: a cross-sectional analysis of the SPLASHY study The Feasibility of Reducing Sitting Time in Overweight and Obese Older Adults The effect of walking mobility on the measurement of physical activity using accelerometry in multiple sclerosis Intervening to Reduce Sedentary Behaviors and Childhood Obesity among School-Age Youth: A Systematic Review of Randomized Trials Accelerometer-measured dose-response for physical activity, sedentary time, and mortality in US adults. A systematic review of school-based interventions targeting physical activity and sedentary behaviour among older adolescents Is Objectively Assessed Sedentary Behavior, Physical Activity and Cardiorespiratory Fitness Linked to Brain Plasticity Outcomes in Old Age?
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 Hip fractures in older persons are associated with both low levels of daily physical activity and loss of outdoor mobility . The aim was to investigate if accelerometer-based measures of physical behaviour can be used to determine if people undertake outdoor walking and to provide reference values for physical behaviour outcomes related to outdoor mobility . Older persons ( n = 245 ) , ≥70 years , one year after hip fracture , participated .  Six objective measures of physical behaviour collected by an activity monitor were compared with self-reported outdoor mobility assessed with the Nottingham Extended ADL scale . All measures of time and length in upright periods were significantly lower in participants who reported not walking outdoors ( p < 0.001 ) . A set of cut-off points for the different physical behaviour variables was generated . Maximum length of upright events discriminated best between groups , with 31 minutes as a threshold to determine if a person is more likely to report that they walk outdoors ( sensitivity : 0.805 , specificity : 0.704 , and AUC : 0.871 ) or 41 minutes or more to determine if a person is more likely to report outdoor walking on their own ( AUC : 0.891 ) . Physical behaviour  variables from activity monitoring can provide information about patterns of physical behaviour related to outdoor activity performance 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 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 : 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 Physical activity ( PA ) is associated with positive cardio-metabolic health and emerging evidence suggests sedentary behavior ( SB ) may be detrimental to children 's health independent of PA . The primary aim of the Transform-Us ! study is to determine whether an 18-month , behavioral and environmental intervention in the school and family setting s results in higher levels of PA and lower rates of SB among 8 - 9 year old children compared with usual practice ( post-intervention and 12-months follow-up ) . The secondary aims are to determine the independent and combined effects of PA and SB on  children 's cardio-metabolic health risk factors ; identify the factors that mediate the success of the intervention ; and determine whether the intervention is cost-effective . Methods / design A four-arm cluster-r and omized controlled trial ( RCT ) with a 2 × 2 factorial design , with schools as the unit of r and omization . Twenty schools will be allocated to one of four intervention groups , sedentary behavior ( SB-I ) , physical activity ( PA-I ) , combined SB and PA ( SB+PA-I ) or current practice control ( C ) , which will be evaluated among approximately 600 children aged 8 - 9 years in school year 3 living in Melbourne , Australia . All children in year 3 at intervention schools in 2010 ( 8 - 9 years ) will receive the intervention over an 18-month period with a maintenance ' booster ' delivered in 2012 and children at all schools will be invited to participate in the evaluation assessment s. To maximize the sample and to capture new students arriving at intervention and control schools , recruitment will be on-going up to the post-intervention time point . Primary outcomes are time spent sitting and in PA assessed via accelerometers and inclinometers and survey . Discussion To our knowledge , Transform-Us ! is the first RCT to examine the effectiveness of intervention strategies for reducing children 's overall sedentary time , promoting PA and optimizing health outcomes . The integration of consistent strategies and messages to children from teachers and parents in both school and family setting s is a critical component of this study , and if shown to be effective , may have a significant impact on educational policies as well as on pedagogical and parenting practice s . Trial registration ACTRN12609000715279 ; Current Controlled Trials IS RCT Objective . To develop an automated and objective method to assess mobility in Parkinson disease ( PD ) patients in daily-life setting s and to investigate whether accelerometer-derived measures discriminate between PD and healthy controls as they walk and simulate activities of daily living ( ADL ) . Methods . Healthy older adults ( 17 ) and patients with PD ( 22 ) wore a triaxial accelerometer on their lower back during short walks ( validation study ) and during a walk around the medical center to simulate daily activities ( ADL simulation ) . The variability ( consistency and rhythmicity ) of stepping was assessed . The patients completed the walks before and after taking their anti-Parkinsonian medications .  Frequency-based acceleration measures included dominant frequency , amplitude ( strength of signal frequency ) , width ( frequency dispersion ) , and slope ( a combination reflecting amplitude and width ) of the main frequency of the power spectral density in the 0.5- to 3.0-Hz b and . A subset of the Unified Parkinson-Disease Rating Scale provided a clinical measure of gait impairment ( UPDRS-Gait5 ) . A PD patient and control wore the sensors for 3 days at home . Results . The width was larger , and the amplitude and slope were smaller in the PD patients compared to the controls in the validation study and ADL simulation ( P < .02 ) . The width decreased , and the amplitude and slope increased when patients took anti-Parkinsonian medications ( P < .007 ) . Significant correlations were observed between acceleration-derived measures and UPDRS-Gait5 . The data obtained at home was similar to the clinic data . Conclusions . Frequency-derived measures are valid and sensitive estimates of stride-to-stride variability that can be used to assess the quality and consistency of walking in patients with PD in real-life setting OBJECTIVES To investigate the associations of objective ly assessed sedentary time , light intensity physical activity ( PA ) , moderate to vigorous intensity PA ( MVPA ) , and total PA with all-cause mortality and mortality from cardiovascular disease ( CVD ) or cancer in a Swedish population -based cohort with 15 years follow-up time . DESIGN Longitudinal prospect i ve cohort study . METHODS Data from 851 persons ( 56 % women ) ≥35 years at baseline were included . Primary exposure variables were  time ( min/day ) spent sedentary , in light intensity PA and in MVPA , and total counts from an Actigraph 7164 accelerometer . Data on all-cause mortality and mortality from CVD or cancer were obtained from Swedish registers . Cox proportional hazards models estimated hazard ratios ( HR ) of mortality with 95 % confidence intervals ( CI ) . RESULTS Compared with the least sedentary participants , those in the most sedentary tertile had an increased risk of all-cause mortality , HR : 2.7 ( 1.4 , 5.3 ) , CVD mortality , HR : 5.5 ( 1.4 , 21.2 ) and cancer mortality , HR : 4.3 ( 1.2 , 16.0 ) . For all-cause mortality , those in the highest light intensity PA tertile had a HR 0.34 ( 0.17 , 0.67 ) compared with the lowest tertile . A similar pattern was found for CVD and cancer mortality . More time spent in MVPA was associated with the largest risk reduction for CVD mortality , with an almost 90 % lower risk in the tertile with the most time in MVPA . CONCLUSIONS This study confirms a strong inverse relationship between MVPA and mortality , and adds new insight for the underst and ing of the associations between sedentary time  and light intensity PA  and mortality 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 ) Background . Overweight and obese older adults have high sedentary time . We tested the feasibility and preliminary effects of a sedentary time reduction intervention among adults over age 60 with a body mass index over 27 kg/m2 using a nonr and omized one-arm design . Methods . Participants ( N = 25 , mean age = 71.4 , mean body mass index = 34 ) completed an 8-week theory-based intervention targeting reduced total sitting time and increased sit-to-st and transitions . An inclinometer ( activPAL ™ ) measured the primary outcomes , change in total sitting time and sit-to-st and transitions . Secondary outcomes included physical activity ( ActiGraph GT3X+ accelerometer ) , self-reported sedentary behaviors , physical function ( Short Physical Performance Battery ) , depressive symptoms ( 8-item Patient Health Question naire ) , quality of life ( PROMIS ) , and study satisfaction . Paired t tests examined pre – post test changes in sitting time , sit-to-st and transitions , and secondary outcomes . Results . Inclinometer measured sitting time decreased by 27 min/day ( p < .05 ) and sit-to-st and transitions increased by 2 per day ( p > .05 ) , while st and ing time increased by 25 min/day ( p < .05 ) . Accelerometer measured sedentary time , light-intensity , and moderate-to-vigorous physical activity improved ( all p values ≤ .05 ) . Self-reported sitting time , gait speed , and depressive symptoms also improved ( all p values < .05 ) . Effect sizes were small . Study satisfaction was high . Conclusions . Reducing sitting time is feasible , and the intervention shows preliminary evidence of effectiveness among older adults with overweight and obesity . R and omized trials of sedentary behavior reduction in overweight and obese older adults , most of whom have multiple chronic conditions , may be promising Objective : To examine whether accelerometry provides a measure of physical activity , walking ability or both in a sample of individuals with multiple sclerosis . The secondary purpose was to examine the validity of physical activity measures in people with multiple sclerosis who have ambulatory impairments . Participants : Forty-two individuals with multiple sclerosis without ambulatory impairment ( Exp and ed Disability Status Scale ( EDSS ) score ≤ 4.5 ) and 32 individuals with multiple sclerosis with ambulatory impairment ( EDSS ≥5.0 ) . Method : Participants completed the Multiple Sclerosis Walking Scale-12 and Performance Scales , wore an accelerometer for seven days , and completed the Godin Leisure-Time Exercise Question naire and short-form of the International Physical Activity Question naire . Results : There were significant differences between groups on scores from the five measures . There were large correlations between the accelerometer counts with scores from both the self-report measures of physical activity and the self-report measures of walking mobility in the overall sample . There were large correlations between scores from both measures of physical activity in the overall sample and the sub sample with ambulatory impairment . Conclusion : Our data suggest that accelerometers are measuring both physical activity and walking mobility in individuals with multiple sclerosis , whereas self-report measures are measuring physical activity in individuals with multiple sclerosis , including those with ambulatory impairment 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 BACKGROUND Moderate-to-vigorous-intensity physical activity is recommended to maintain and improve health , but the mortality benefits of light activity and risk for sedentary time remain uncertain . OBJECTIVES Using accelerometer-based measures , we 1 ) described the mortality dose-response for sedentary time and light- and moderate-to-vigorous-intensity activity using restricted cubic splines , and 2 ) estimated the mortality benefits associated with replacing sedentary time with physical activity , accounting for total activity . DESIGN US adults ( n = 4840 ) from NHANES ( 2003 - 2006 ) wore an accelerometer for ≤7 d and were followed prospect ively for mortality . Proportional hazards models were used to estimate adjusted HRs and 95 % CIs for mortality associations with time spent sedentary and in light- and moderate-to-vigorous-intensity physical activity . Splines were used to graphically present behavior-mortality relation . Isotemporal models estimated replacement associations for sedentary time , and separate models were fit for low- ( < 5.8 h total activity/d ) and high-active participants to account for nonlinear associations . RESULTS Over a mean of 6.6 y , 700 deaths occurred . Compared with less-sedentary adults ( 6 sedentary h/d ) , those who spent 10 sedentary h/d had 29 % greater risk ( HR : 1.29 ; 95 % CI : 1.1 , 1.5 ) . Compared with those who did less light activity ( 3 h/d ) , those who did 5 h of light activity/d had 23 % lower risk ( HR : 0.77 ; 95 % CI : 0.6 , 1.0 ) . There was no association with mortality for sedentary time or light or moderate-to-vigorous activity in highly active adults . In less-active adults , replacing 1 h of sedentary time with either light- or moderate-to-vigorous-intensity activity was associated with 18 % and 42 % lower mortality , respectively . CONCLUSIONS Health promotion efforts for physical activity have mostly focused on moderate-to-vigorous activity . However , our findings derived from accelerometer-based measurements suggest that increasing light-intensity activity and reducing sedentary time are also important , particularly for inactive adults 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 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
These studies indicate that analysis of the data using 60-s epochs and a vertical magnitude cut-point < 200 cpm or using 30- or 60-s epochs with a machine learning algorithm provides the most valid estimates of SB .
Conclusions Few studies have examined the reliability and validity of accelerometers for measuring SB  in older adults .
Studies to date suggest that the criteria research ers use for classifying an epoch as sedentary instead of as non-wear time ( e.g. , the non-wear algorithm used ) may need to be different for older adults than for younger adults .
The required number of hours and days of wear for valid estimates of SB in older adults was not clear from studies to date .
Background The evidence showing the ill health effects of prolonged sedentary behaviour ( SB ) is growing .
Most studies of  SB in older adults have relied on self-report measures of SB .
However , SB is difficult for older adults to recall and objective measures that combine accelerometry with inclinometry are now available for more accurately assessing SB .
The aim of this systematic review was to assess the validity and reliability of these accelerometers for the assessment of  SB in older adults .