title: Relative Importance of Step Count, Intensity, and Duration on Physical Activity's Impact on Vascular Structure and Function in Previously Sedentary Older Adults Vitamin d and physical activity status: associations with five-year changes in body composition and muscle function in community-dwelling older adults. Breaking prolonged sitting reduces postprandial glycemia in healthy, normal-weight adults: a randomized crossover trial. Physical activity attenuates age-related biomarker alterations in preclinical AD Reducing Sedentary Behavior Versus Increasing Moderate-to-Vigorous Intensity Physical Activity in Older Adults Prescribing Physical Activity Through Primary Care: Does Activity Intensity Matter? Motivational counseling to reduce sitting time: a community-based randomized controlled trial in adults. Too much sitting: the population health science of sedentary behavior. Breaking up prolonged sitting reduces resting blood pressure in overweight/obese adults. A randomized controlled trial of resistance exercise training to improve glycemic control in older adults with type 2 diabetes. European Sitting Championship: Prevalence and Correlates of Self-Reported Sitting Time in the 28 European Union Member States Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable Ability of physical activity measurements to assess health-related risks Higher mitochondrial respiration and uncoupling with reduced electron transport chain content in vivo in muscle of sedentary versus active subjects. Circadian profile of cardiac autonomic nervous modulation in healthy subjects: differing effects of aging and gender on heart rate variability. Social relations, physical activity, and well-being in older adults. A randomized trial investigating the 12-month changes in physical activity and health outcomes following a physical activity consultation delivered by a person or in written form in Type 2 diabetes: Time2Act. Television viewing time and weight gain in colorectal cancer survivors: a prospective population-based study Sedentary time and markers of inflammation in people with newly diagnosed type 2 diabetes Television Viewing Time is Associated with Overweight/Obesity Among Older Adults, Independent of Meeting Physical Activity and Health Guidelines Effect of physical activity level on biomarkers of inflammation and insulin resistance over 5 years in outpatients with coronary heart disease (from the Heart and Soul Study).
abstract: Background Age‐related endothelial dysfunction and vascular stiffening are associated with increased cardiovascular ( CV ) risk . Many groups have encouraged goals of ≥10 000 steps/day or ≥30 min/day of moderate intensity physical activity ( MPA ) to reduce age‐related CV risk . The impact of MPA on the vasculature of older adults remains unclear . Methods and Results We r and omized 114 sedentary older adults ages ≥50 to 12 weeks of either no intervention ( group 1 ) , a pedometer‐only intervention ( group 2 ) , or a pedometer with an interactive website employing strategies to increase the adoption of habitual physical activity ( PA , group 3 ) . Endothelial function by brachial flow‐mediated dilation ( FMD% ) , vascular stiffness by tonometry , step‐count by pedometer , and PA intensity/distribution by accelerometer were measured . Step‐count increased in groups 2 ( 5136±1554 to 9596±3907 , P<0.001 ) and 3 ( 5474±1512 to 8167±3111 , P<0.001 ) but not in group 1 ( 4931±1667 to 5410±2410 ) . Both groups 2 and 3 increased MPA ≥30 min/day . Only group 3 increased MPA in continuous bouts of ≥10 minutes ( P<0.001 ) and improved FMD% ( P=0.001 ) . Neither achievement of ≥10 000 steps/day nor ≥30 min/day of MPA result ed in improved FMD% . However , achieving ≥20 min/day in MPA bouts result ed in improved FMD% . No changes in vascular stiffness were observed . Conclusions MPA reverses age‐related endothelial dysfunction , but may require MPA to be performed in bouts of ≥10 minutes duration for ≥20 min/day to be effective . Commonly encouraged PA goals do not guarantee improved endothelial function and may not be as effective in reducing CV risk . Clinical Trial Registration URL : Clinical trials.gov . Unique identifier : NCT‐01212978 CONTEXT High vitamin D and physical activity ( PA ) levels are independently associated with improved body composition and muscle function in older adults . OBJECTIVE The objective of this study was to investigate the interaction of 25-hydroxyvitamin D ( 25OHD ) and PA status in maintenance of body composition and muscle function in older adults . DESIGN AND SETTING This was a 5-year prospect i ve population -based study of Australian community-dwelling older adults . PARTICIPANTS Participants in the study included 615 community-dwelling volunteers aged 50 years old or older [ 61.4 ± 6.9 ( mean ± SD ) y ; 48 % female ] r and omly selected from electoral rolls and categorized according to baseline serum 25OHD ( ≥ or < 50 nmol/L ) and PA ( ≥ or < 10,000 pedometer determined steps/d ) levels as follows : high 25OHD and high PA ( VitD+PA+ ) ; high 25OHD and low PA ( VitD+PA- ) ; low 25OHD and high PA ( VitD-PA+ ) ; and low 25OHD and low PA ( VitD-PA- ) . A subset of 518 participants completed accelerometer assessment s during follow-up . MAIN OUTCOME MEASURES Changes in dual-energy X-ray absorptiometry-assessed body composition and lower-limb muscle function were measured . RESULTS VitD+PA+ had significantly smaller increases in body fat over 5 years compared with other groups ( all P < .05 ) . Higher baseline pedometer-determined PA result ed in declines in total body fat ( β = -.23 kg per 100 steps/d , P = .001 ) over 5 years for participants with high 25OHD but not those with low 25OHD ( P > .05 ) . Among participants with accelerometer data , these associations were generally mediated by higher levels of moderate/vigorous PA . CONCLUSIONS High vitamin D status appears to enhance PA-related declines in body fat during aging , but the mechanism may be greater amounts of outdoor moderate/vigorous PA rather than a direct effect of 25OHD BACKGROUND Sedentary behavior is a risk factor for cardiometabolic disease . Regularly interrupting sedentary behavior with activity breaks may lower this risk . OBJECTIVE We compared the effects of prolonged sitting , continuous physical activity combined with prolonged sitting , and regular activity breaks on  postpr and ial metabolism . DESIGN Seventy adults participated in a r and omized crossover study . The prolonged sitting intervention involved sitting for 9 h , the physical activity intervention involved walking for 30 min and then sitting , and the regular-activity-break intervention involved walking for 1 min 40 s every 30 min . Participants consumed a meal-replacement beverage at 60 , 240 , and 420 min . RESULTS The plasma incremental area under the curve ( iAUC ) for insulin differed between interventions ( overall P < 0.001 ) . Regular activity breaks lowered values by 866.7 IU · L(-1 ) · 9 h(-1 ) ( 95 % CI : 506.0 , 1227.5 IU · L(-1 ) · 9 h(-1 ) ; P < 0.001 ) when compared with prolonged sitting and by 542.0 IU · L(-1 ) · 9 h(-1 ) ( 95 % CI : 179.9 , 904.2 IU · L(-1 ) · 9 h(-1 ) ; P = 0.003 ) when compared with physical activity . Plasma glucose iAUC also differed between interventions ( overall P < 0.001 ) . Regular activity breaks  lowered values by 18.9 mmol · L(-1 ) · 9 h(-1 ) ( 95 % CI : 10.0 , 28.0 mmol · L(-1 ) · 9 h(-1 ) ; P < 0.001 ) when compared with prolonged sitting and by 17.4 mmol · L(-1 ) · 9 h(-1 ) ( 95 % CI : 8.4 , 26.3 mmol · L(-1 ) · 9 h(-1 ) ; P < 0.001 ) when compared with physical activity . Plasma triglyceride iAUC differed between interventions ( overall P = 0.023 ) . Physical activity  lowered values by 6.3 mmol · L(-1 ) · 9 h(-1 ) ( 95 % CI : 1.8 , 10.7 mmol · L(-1 ) · 9 h(-1 ) ; P = 0.006 ) when compared with regular activity breaks . CONCLUSION Regular activity breaks were more effective than continuous physical activity at decreasing postpr and ial glycemia and insulinemia in healthy , normal-weight adults . This trial was registered with the Australian New Zeal and Clinical Trials registry as ACTRN12610000953033 Objective : To examine whether engagement in physical activity might favorably alter the age-dependent evolution of Alzheimer disease (AD)-related brain and cognitive changes in a cohort of at-risk , late-middle-aged adults . Methods : Three hundred seventeen enrollees in the Wisconsin Registry for Alzheimer 's Prevention underwent  T1 MRI ; a subset also underwent 11C-Pittsburgh compound B – PET ( n = 186 ) and 18F-fluorodeoxyglucose – PET ( n = 152 ) imaging . Participants ' responses on a self-report measure of current physical activity were used to classify them as either physically active or physically inactive based on American Heart Association guidelines . They also completed a comprehensive neuropsychological battery . Covariate-adjusted regression analyses were used to test whether the adverse effect of age on imaging and cognitive biomarkers was modified by physical activity . Results : There were significant age × physical activity interactions for β-amyloid burden ( p = 0.014 ) , glucose metabolism ( p = 0.015 ) , and hippocampal volume ( p = 0.025 ) such that , with advancing age , physically active individuals exhibited a lesser degree of biomarker alterations compared with the physically inactive . Similar age × physical activity interactions were also observed on cognitive domains of Immediate Memory ( p = 0.042 ) and Visuospatial Ability ( p = 0.016 ) . In addition , the physically active group had higher scores on Speed and Flexibility ( p = 0.002 ) compared with the inactive group . Conclusions : In a middle-aged , at-risk cohort , a physically active lifestyle is associated with an attenuation of the deleterious influence of age on key biomarkers of AD pathophysiology . However , because our observational , cross-sectional design can not establish causality , r and omized controlled trials/longitudinal studies will be necessary for determining whether midlife participation in structured physical exercise forestalls the development of AD and related disorders in later life 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 Abstract Background : Physical activity guidelines recommend engaging in moderate- and vigorous-intensity physical activity to elicit health benefits . Similarly , these higher intensity ranges for activity are typically targeted in healthy living interventions ( ie , exercise prescription ) . Comparatively less attention has been focused on changing lower intensity physical activity ( ie , sedentary activity ) behaviors . The purpose of this study was to explore the effects of prescribing changes to physical activity of various intensities ( ie , sedentary through exercise ) through the primary care setting . Methods : Sixty older adults ( aged 55–75 years ; mean age 63 ± 5 years ) volunteered to participate , and were r and omly assigned to 4 groups : 3 receiving an activity prescription intervention targeting a specific intensity of physical activity ( exercise , sedentary , or both ) , and 1 control group . During the 12-week intervention period participants followed personalized activity programs at home . Basic clinical measures ( anthropometrics , blood pressure , aerobic fitness ) and blood panel for assessing cardiometabolic risk ( glucose , lipid profile ) were conducted at baseline ( week 0 ) and follow-up ( week 12 ) in a primary care office . Results : There were no differences between groups at baseline ( P > 0.05 ) . The intervention changed clinical ( F(5 , 50 ) = 20.458 , P = 0.000 , ηP2 = 0.672 ) and blood panel measures ( F(5 , 50 ) = 4.576 , P = 0.002 , ηP2 = 0.314 ) of cardiometabolic health . Post hoc analyses indicted no differences between groups ( P > 0.05 ) . Conclusion : Physical activity prescription of various intensities through the primary care setting improved cardiometabolic health status . To our knowledge , this is the first report of sedentary behavior prescription ( alone , or combined with exercise ) in primary care . The findings support the ongoing practice of fitness assessment and physical activity prescription for chronic disease management and prevention BACKGROUND Sedentary behavior is regarded as a distinct risk factor for cardiometabolic morbidity and mortality , but knowledge of the efficacy of interventions targeting reductions in sedentary behavior is limited . PURPOSE To investigate the effect of an individualized face-to-face motivational counseling intervention aim ed at reducing sitting time . DESIGN A r and omized , controlled , observer-blinded , community-based trial with two parallel groups using open-end r and omization with 1:1 allocation . SETTING / PARTICIPANTS A total of 166 sedentary adults were consecutively recruited from the population -based Health2010 Study . INTERVENTION Participants were r and omized to a control ( usual lifestyle ) or intervention group with four individual theory-based counseling sessions . MAIN OUTCOME MEASURES Objective ly measured overall sitting time ( ActivPAL 3TM , 7 days ) ; secondary measures were breaks in sitting time , anthropometric measures , and cardiometabolic biomarkers , assessed at baseline and after 6 months . Data were collected in 2010 - 2012 and analyzed in 2013 - 2014 using repeated measures multiple regression analyses . RESULTS Ninety-three participants were r and omized to the intervention group and 73 to the control group , and 149 completed the study . The intervention group had a mean sitting time decrease of -0.27 hours/day , corresponding to 2.9 % of baseline sitting time ( hours/day ) ; the control group increased mean sitting time by 0.06 hours/day . The between-group difference in change , -0.32 hours/day ( 95 % CI=-0.87 , 0.24 , p=0.26 ) , was not statistically significant . Significant differences in change in fasting serum insulin of -5.9 pmol/L ( 95 % CI=-11.4 , -0.5 , p=0.03 ) ; homeostasis model assessment -estimated insulin resistance of -0.28 ( 95 % CI=-0.53 , -0.03 , p=0.03 ) ; and waist circumference of -1.42 cm ( 95 % CI=-2.54 , -0.29 , p=0.01 ) were observed in favor of the intervention group . CONCLUSIONS Although the observed decrease in sitting time was not significant , a community-based , individually tailored , theory-based intervention program aim ed at reducing sitting time may be effective for increasing st and ing and improving cardiometabolic health in sedentary adults . TRIAL REGISTRATION This study is registered at Clinical trials.gov ( NCT00289237 ) Even when adults meet physical activity guidelines , sitting for prolonged periods can compromise metabolic health .  Television ( TV ) time and objective measurement studies show deleterious associations , and breaking up sedentary time is beneficial .  Sitting time , TV time , and time sitting in automobiles increase premature mortality risk . Further evidence from prospect i ve studies , intervention trials , and population -based behavioral studies is required AIM To compare the effect of 7 h of prolonged sitting on resting blood pressure with a similar duration of sitting combined with intermittent brief bouts of light-intensity or moderate-intensity physical activity . METHODS AND RESULTS Overweight/obese adults ( n = 19 ; aged 45 - 65 years ) were recruited for a r and omized three-treatment crossover trial with a one-week washout between treatments : 1 ) uninterrupted sitting ; 2 ) sitting with 2 min bouts of light-intensity walking at 3.2 km/h every 20 min ; and , 3 ) sitting with 2 min bouts of moderate-intensity walking at between 5.8 and 6.4 km/h every 20 min . After an initial 2 h period seated , participants consumed a test meal ( 75 g carbohydrate , 50 g fat ) and completed each condition over the next 5 h. Resting blood pressure was assessed oscillometrically every hour as a single measurement , 5 min prior to each activity bout . GEE models were adjusted for sex , age , BMI , fasting blood pressure and treatment order . After adjustment for potential confounding variables , breaking up prolonged sitting with light and moderate-intensity activity breaks was associated with lower systolic blood pressure [ light : 120 ± 1 mmHg ( estimated marginal mean ± SEM ) , P = 0.002 ; moderate : 121 ± 1 mmHg , P = 0.02 ] , compared to uninterrupted sitting ( 123 ± 1 mmHg ) . Diastolic blood pressure was also significantly lower during both of the activity conditions ( light : 76 ± 1 mmHg , P = 0.006 ; moderate : 77 ± 1 mmHg , P = 0.03 ) compared to uninterrupted sitting ( 79 ± 1 mmHg ) . No significant between-condition differences were observed in mean arterial pressure or heart rate . CONCLUSION Regularly breaking up prolonged sitting may reduce systolic and diastolic blood pressure . TRIAL REGISTRATION NUMBER ACTRN12609000656235 ( http://www.anzctr.org.au ) TRIAL REGISTRATION DATE : August 4th 2009 OBJECTIVE To determine the efficacy of high-intensity progressive resistance training ( PRT ) on glycemic control in older adults with type 2 diabetes . RESEARCH DESIGN AND METHODS We performed a 16-week r and omized controlled trial in 62 Latino older adults ( 40 women and 22 men ; mean + /- SE age 66 + /- 8 years ) with type 2 diabetes r and omly assigned to supervised PRT or a control group .  Glycemic control , metabolic syndrome abnormalities , body composition , and muscle glycogen stores were determined before and after the intervention . RESULTS Sixteen weeks of PRT ( three times per week ) result ed in reduced plasma glycosylated hemoglobin levels ( from 8.7 + /- 0.3 to 7.6 + /- 0.2 % ) , increased muscle glycogen stores ( from 60.3 + /- 3.9 to 79.1 + /- 5.0 mmol glucose/kg muscle ) , and reduced the dose of prescribed diabetes medication in 72 % of exercisers compared with the control group , P = 0.004 - 0.05 . Control subjects showed no change in glycosylated hemoglobin , a reduction in muscle glycogen ( from 61.4 + /- 7.7 to 47.2 + /- 6.7 mmol glucose/kg muscle ) , and a 42 % increase in diabetes medications . PRT subjects versus control subjects also increased lean mass ( + 1.2 + /- 0.2 vs. -0.1 + /- 0.1 kg ) , reduced systolic blood pressure ( -9.7 + /- 1.6 vs. + 7.7 + /- 1.9 mmHg ) , and decreased trunk fat mass ( -0.7 + /- 0.1 vs. + 0.8 + /- 0.1 kg ; P = 0.01 - 0.05 ) . CONCLUSIONS PRT as an adjunct to st and ard of care is feasible and effective in improving glycemic control and some of the abnormalities associated with the metabolic syndrome among high-risk older adults with type 2 diabetes Objective Sedentary behaviour is increasingly recognized as an important health risk , but comparable data across Europe are scarce . The objective of this study was to explore the prevalence and correlates of self-reported sitting time  in adults across and within the 28 European Union Member States . Methods This study reports data from the Special Eurobarometer 412 . In 2013 , 27,919 r and omly selected Europeans ( approximately 1000 per Member State ) were interviewed face-to-face . Sitting time on a usual day was self-reported and dichotomised into sitting less- and more than 7.5 hours per day . Uni- and multivariate odds ratios of sitting more than 7.5 hours per day were assessed by country and socio-demographic variables using binary logistic regression analyses . The analyses were stratified by country to study the socio-demographic correlates of sitting time within the different countries . Results A total of 26,617 respondents were included in the analyses .  Median sitting time was five hours per day . Across Europe , 18.5 percent of the respondents reported to sit more than 7.5 hours per day , with substantial variation between countries ( ranging from 8.9 to 32.1 percent ) . In general , northern European countries reported more sitting than countries in the south of Europe . ‘ Current occupation ’ and ‘ age when stopped education ’ were found to be the strongest correlates of sitting time , both across Europe and within most Member States . Compared to manual workers , the odds ratio of sitting more than 7.5 hours per day was 5.00 for people with white collar occupations , 3.84 for students , and 3.65 for managers . Conclusions There is substantial variation in self-reported sitting time among European adults across countries as well as socio-demographic groups . While regular surveillance of ( objective ly measured ) sedentary behaviour is needed , the results of this study provide entry points for developing targeted interventions aim ed at highly sedentary population s , such as people with sedentary occupations Background Epidemiological studies suggest that excessive sitting time is associated with increased health risk , independent of the performance of exercise . We hypothesized that a daily bout of exercise can not compensate the negative effects of inactivity during the rest of the day on insulin sensitivity and plasma lipids . Methodology /Principal Findings Eighteen healthy subjects , age 21±2 year , BMI 22.6±2.6 kgm−2 followed r and omly three physical activity regimes for four days . Participants were instructed to sit 14 hr/day ( sitting regime ) ; to sit 13 hr/day and to substitute 1 hr of sitting with vigorous exercise 1 hr ( exercise regime ) ; to substitute 6 hrs sitting with 4 hr walking and 2 hr st and ing ( minimal intensity physical activity ( PA ) regime ) . The sitting and exercise regime had comparable numbers of sitting hours ; the exercise and minimal intensity PA regime had the same daily energy expenditure . PA was assessed continuously by an activity monitor ( ActivPAL ) and a diary . Measurements of insulin sensitivity ( oral glucose tolerance test , OGTT ) and plasma lipids were performed in the fasting state , the morning after the 4 days of each regime . In the sitting regime , daily energy expenditure was about 500 kcal lower than in both other regimes . Area under the curve for insulin during OGTT was significantly lower after the minimal intensity PA regime compared to both sitting and exercise regimes 6727.3±4329.4 vs 7752.0±3014.4 and 8320.4±5383.7 mU•min/ml , respectively . Triglycerides , non-HDL cholesterol and apolipoprotein B plasma levels improved significantly in the minimal intensity PA regime compared to sitting and showed non-significant trends for improvement compared to exercise . Conclusions One hour of daily physical exercise can not compensate the negative effects of inactivity on insulin level and plasma lipids if the rest of the day is spent sitting . Reducing inactivity by increasing the time spent walking/st and ing is more effective than one hour of physical exercise , when energy expenditure is kept constant The aim of this study is to evaluate if two different physical activity ( PA ) question naires have similar ability to rank individuals , and to examine associations with cardiovascular-metabolic risk factors , compared to an objective measure . In a r and om sample ( n=369 , age : 65±6 years ) from the population -based ‘ Malmö Diet and Cancer ’ ( MDC ) cohort , PA was measured by a leisure-time comprehensive question naire ( MDC-score ) , a simple leisure-time question naire and by accelerometer-monitoring ( CSA ) . Moderate correlations were observed between MDC-score and CSA in men and women ( r=0.35 and 0.24 , respectively ) . In men , both question naires and CSA were inversely associated with waist circumference , insulin resistance and metabolic syndrome . In women , the MDC-score was positively associated with high-density lipoprotein-cholesterol , and the simple question naire inversely associated with anthropometric indexes , but no association was seen between PA estimates and cardiovascular components . We conclude that both PA question naires distinguish health risks associated with anthropometric-metabolic risk factors , particularly in men OBJECTIVE This study investigated the disparity between muscle metabolic rate and mitochondrial metabolism in human muscle of sedentary vs. active individuals . RESEARCH DESIGN AND METHODS Chronic activity level was characterized by a physical activity question naire and a triaxial accelerometer as well as a maximal oxygen uptake test . The ATP and O(2 ) fluxes and mitochondrial coupling ( ATP/O(2 ) or P/O ) in resting muscle as well as mitochondrial capacity ( ATP(max ) ) were determined in vivo in human vastus lateralis muscle using magnetic resonance and optical spectroscopy on 24 sedentary and seven active subjects . Muscle biopsies were analyzed for electron transport chain content ( using complex III as a representative marker ) and mitochondrial proteins associated with antioxidant protection . RESULTS Sedentary muscle had lower electron transport chain complex content ( 65 % of the active group ) in proportion to the reduction in ATP(max ) ( 0.69 ± 0.07 vs. 1.07 ± 0.06 mM sec(-1 ) ) as compared with active subjects . This lower ATP(max ) paired with an unchanged O(2 ) flux in resting muscle between groups result ed in a doubling of O(2 ) flux per ATP(max ) ( 3.3 ± 0.3 vs. 1.7 ± 0.2 μM O(2 ) per mM ATP ) that reflected mitochondrial uncoupling ( P/O = 1.41 ± 0.1 vs. 2.1 ± 0.3 ) and greater UCP3/complex III ( 6.0 ± 0.7 vs. 3.8 ± 0.3 ) in sedentary vs. active subjects . CONCLUSION A smaller mitochondrial pool serving the same O(2 ) flux result ed in elevated mitochondrial respiration in sedentary muscle . In addition , uncoupling contributed to this higher mitochondrial respiration . This finding resolves the paradox of stable muscle metabolism but greater mitochondrial respiration in muscle of inactive vs. active subjects UNLABELLED Circadian Profile of Heart Rate Variability . INTRODUCTION Although heart rate variability ( HRV ) has been established as a tool to study cardiac autonomic activity , almost no data are available on the circadian patterns of HRV in healthy subjects aged 20 to 70 years . METHODS AND RESULTS We investigated 166 healthy volunteers ( 81 women and 85 men ; age 42 + /- 15 years , range 20 - 70 ) without evidence of cardiac disease .  Time-domain HRV parameters were determined from 24-hour Holter monitoring and calculated as hourly mean values and mean 24-hour values . All volunteers were fully mobile , awoke around 7 A.M. , and had 6 to 8 hours of sleep . Circadian profiles of vagus-associated HRV parameters revealed a marked day-night pattern , with a peak at nighttime and a plateau at daytime . The characteristic nocturnal peak and the day-night amplitude diminished with aging by decade . Estimates of overall HRV ( geometric triangular index [ TI ] , SD of NN intervals [ SDNN ] ) and long-term components of HRV ( SD of the averages of NN intervals for all 5-min segments [ SDANN ] ) were low at nighttime and increased in the morning hours . There was a significant decline of 24-hour values of all HRV parameters ( P < 0.001 ) and a strong negative correlation ( P < 0.001 ) with increasing age . Mean 24-hour RR interval ( P < 0.001 ) , SDNN , mean SD of NN intervals for all 5-minute intervals ( SDNNi ) , and SDANN ( all P < 0.01 ) were significantly higher in men . Younger men also exhibited significantly higher values for vagus-associated parameters ( root mean square successive difference [ rMSSD ] , P < 0.05 ; SDNNi , P < 0.01 ) ; however , gender differences diminished with increasing age . CONCLUSION Normal aging is associated with a constant decline of cardiac vagal modulation due to a significant decrease of nocturnal parasympathetic activity . The significant gender-related difference of HRV decreases with aging . These findings emphasize the need to determine age- , gender- , and nycthemeral-dependent normal ranges for HRV assessment BACKGROUND A r and omized controlled trial was conducted to examine : ( a ) the effect of two physical activity modes on changes in subjective well-being ( SWB ) over the course of a 12-month period in older , formerly sedentary adults ( N = 174 , M age = 65.5 years ) and ( b ) the role played by physical activity participation and social support in changes in SWB over time . METHOD Participants were r and omized into either an aerobic activity group or a stretching and toning group . Structural equation modeling was employed to conduct multiple sample latent growth curve analyses of individual growth in measures of SWB ( happiness , satisfaction with life , and loneliness ) over time . RESULTS A curvilinear growth pattern was revealed with well-being significantly improving over the course of the intervention followed by significant declines at the 6-month follow-up . Subsequent structural analyses were conducted showing that frequency of exercise participation was a significant predictor of improvement in satisfaction with life , whereas social relations were related to increases in satisfaction with life and reductions in loneliness . Improvements in social relations and exercise frequency also helped to buffer the declines in satisfaction with life at follow-up . CONCLUSIONS It appears that social relations integral to the exercise environment are significant determinants of subjective well-being in older adults . Findings are discussed in terms of how physical activity environments might be structured to maximize improvements in more global well-being constructs such as satisfaction with life BACKGROUND AND AIMS Physical activity is a cornerstone of Type 2 diabetes management but is underutilized . Physical activity consultations increase physical activity in people with Type 2 diabetes but re sources are often limited . Time2Act is a r and omized control trial to study the 12-month effectiveness of a physical activity consultation delivered by a person or in written form , in contrast to st and ard care , for people with Type 2 diabetes . METHODS A total of 134 inactive people with Type 2 diabetes in a contemplation or preparation stage were r and omized to either intervention or st and ard care .  Objective ( accelerometer ) and subjective ( 7-day recall ) physical activity levels were measured over 1 week , along with physiological [ blood pressure , body mass index ( BMI ) , waist circumference ] and biochemical [ glycated haemoglobin ( HbA(1c ) ) , total and high-density lipoprotein ( HDL ) cholesterol ] measures at baseline , 6 and 12 months . RESULTS Neither a physical activity consultation delivered by a person nor in written form was better than st and ard care at increasing physical activity levels or improving health outcomes in the full study cohort . Total and HDL cholesterol , waist circumference and both systolic and diastolic blood pressure improved over 12 months in all groups , whilst HbA(1c ) improved over 6 months . In a subgroup ( baseline pedometer steps < 5000/day ) , the physical activity consultation delivered by a person significantly increased physical activity over 12 months and the st and ard care group significantly decreased . CONCLUSIONS More research is needed which not only investigates the most economical and effective methods to promote physical activity , but also the best setting to conduct physical activity consultations and the participant factors affecting uptake of physical activity in Type 2 diabetes Objective To investigate the prospect i ve relationships between television viewing time and weight gain in the 3 years following colorectal cancer diagnosis for 1,867 colorectal cancer survivors ( body mass index ( BMI ) ≥ 18.5 kg/m2 ) . Methods  BMI , television viewing time , physical activity , and socio-demographic and clinical covariates  were assessed at baseline ( 5 months ) , 24 months and 36 months post-diagnosis . Multiple linear regression was used to study independent associations between baseline television  viewing time and BMI at 24 and 36 months post-diagnosis . Results At both follow-up time points , there was a significant increase in mean BMI for participants reporting ≥5 h/day of television viewing compared to those watching <3 h/day at baseline ( 24 months : 0.72 kg/m2 ( 0.31 , 1.12 ) , p < 0.001 ; 36 months : 0.61 kg/m2 ( 0.14 , 1.07 ) , p = 0.01 ) , independent of baseline BMI , gender , age , education , marital status , smoking , cancer site , cancer disease stage , treatment mode and co-morbidities . Additional adjustment for baseline physical activity did not change results . Conclusions These findings suggest that a greater emphasis on decreasing television viewing time  could help reduce weight gain among colorectal cancer survivors . This , in turn , could contribute to a risk reduction for co-morbid conditions such as type 2 diabetes and cardiovascular disease Background and aims We investigated whether objective ly measured sedentary time was associated with markers of inflammation in adults with newly diagnosed type 2 diabetes . Methods and results We studied 285 adults ( 184 men , 101 women , mean age 59.0 ± 9.7 ) who had been recruited to the Early ACTivity in Diabetes ( Early ACTID ) r and omised controlled trial .  C-reactive protein ( CRP ) , adiponectin , soluble intracellular adhesion molecule-1 ( sICAM-1 ) , interleukin-6 ( IL-6 ) , and accelerometer-determined sedentary time and moderate-vigorous physical activity ( MVPA ) were measured at baseline and after six-months . Linear regression analysis was used to investigate the independent cross-sectional and longitudinal associations of sedentary time  with markers of inflammation . At baseline , associations between sedentary time and IL-6 were observed in men and women , an association that was attenuated following adjustment for waist circumference . After 6 months of follow-up  , sedentary time was reduced by 0.4 ± 1.2 h per day in women , with the change in sedentary time predicting CRP at follow-up . Every hour decrease in sedentary time  between baseline and six-months was associated with 24 % ( 1 , 48 ) lower CRP . No changes in sedentary time between baseline and 6 months were seen in men . Conclusions  Higher sedentary time  is associated with IL-6 in men and women with type 2 diabetes , and reducing sedentary time is associated with improved levels of CRP in women . Interventions to reduce sedentary time may help to reduce inflammation in women with type 2 diabetes Background Previous studies have shown associations of sedentary behavior with cardiovascular risk , independent of moderate-to-vigorous physical activity ( MVPA ) . However , few studies have focused on older adults . This study examined the joint associations of  television ( TV ) viewing time and MVPA with overweight/obesity among Japanese older adults . Methods A population -based , cross-sectional mail survey was used to collect self-reported height , weight , time spent in TV viewing , and MVPA from 1806 older adults ( age : 65–74 years , men : 51.1 % ) . Participants were classified into 4 categories according to  TV viewing time  ( dichotomized into high and low around the median ) and  MVPA level ( dichotomized into sufficient and insufficient by the physical activity guideline level of ≥150 minutes/week ) . Odds ratios ( ORs ) for overweight/obesity ( body mass index ≥25 kg/m2 ) were calculated according to the 4 TV/MVPA categories , adjusting for potential confounders . Results Of all participants , 20.1 % were overweight/obese . The median TV viewing time ( 25th , 75th percentile ) was 840 ( 420 , 1400 ) minutes/week . As compared with the reference category ( high TV/insufficient MVPA ) , the adjusted ORs ( 95 % CI ) of overweight/obesity were 0.93 ( 0.65 , 1.34 ) for high TV/sufficient MVPA , 0.58 ( 0.37 , 0.90 ) for low TV/insufficient MVPA , and 0.67 ( 0.47 , 0.97 ) for low TV/sufficient MVPA . Conclusions In this sample of older adults , spending less time watching TV , a predominant sedentary behavior , was associated with lower risk of being overweight or obese , independent of meeting physical activity guidelines . Further studies using prospect i ve and /or intervention design s are warranted to confirm the presently observed effects of sedentary behavior , independent of physical activity , on the health of older adults Higher levels of physical activity are associated with lower rates of coronary heart disease ( CHD ) . Previous studies have suggested that this is due partly to lower levels of inflammation and insulin resistance . The aim of this study was to determine whether physical activity level was associated with inflammation or insulin resistance during a 5-year period in out patients with known CHD . A total of 656 participants from the Heart and Soul Study , a prospect i ve cohort study of out patients with documented CHD , were evaluated .  Self-reported physical activity frequency was assessed at baseline and after 5 years of follow-up . Participants were classified as low versus high activity at each visit , yielding 4 physical activity groups : stable low activity , decreasing activity ( high at baseline to low at year 5 ) , increasing activity ( low at baseline to high at year 5 ) , and stable high activity . Year 5 markers of inflammation ( C-reactive protein [ CRP ] , interleukin-6 , and fibrinogen ) and insulin resistance ( insulin , glucose , and glycated hemoglobin ) were compared across the 4 activity groups . After 5 years of follow-up , higher activity was associated with lower mean levels of all biomarkers . In the fully adjusted regression models , CRP , interleukin-6 , and glucose remained independently associated with physical activity frequency ( log CRP , p for trend across activity groups = 0.03 ; log interleukin-6 , p for trend = 0.01 ; log glucose , p for trend = 0.003 ) . Subjects with stable high activity typically had the lowest levels of biomarkers . In conclusion , in this novel population of out patients with known CHD followed for 5 years , higher physical activity frequency was independently associated with lower levels of CRP , interleukin-6 , and glucose
target: 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 .
background: 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 .