title: American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Maintaining a Healthy BMI: Data From a 16-Year Study of Young Australian Women. Prospective association between body composition, physical activity and energy intake in young adults Breaking prolonged sitting reduces postprandial glycemia in healthy, normal-weight adults: a randomized crossover trial. A Randomised Controlled Trial to Reduce Sedentary Time in Young Adults at Risk of Type 2 Diabetes Mellitus: Project STAND (Sedentary Time ANd Diabetes) High sitting time or obesity: Which came first? Bidirectional association in a longitudinal study of 31,787 Australian adults Prospective study of the association of changes in dietary intake, physical activity, alcohol consumption, and smoking with 9-y gain in waist circumference among 16 587 US men. Breaking Up Prolonged Sitting Reduces Postprandial Glucose and Insulin Responses The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials Sitting Behavior and Obesity Sedentary Behaviours in Mid-Adulthood and Subsequent Body Mass Index Physical Activity, Television Viewing Time, and 12-Year Changes in Waist Circumference Predictors of weight change in men: Results from The Health Professionals Follow-Up Study Physical activity in relation to development and maintenance of obesity in men with and without juvenile onset obesity Television viewing and long-term weight maintenance: results from the National Weight Control Registry. Benefits for Type 2 Diabetes of Interrupting Prolonged Sitting With Brief Bouts of Light Walking or Simple Resistance Activities Television watching and other sedentary behaviors in relation to risk of obesity and type 2 diabetes mellitus in women. Associations between sitting time and weight in young adult Australian women. Energy Expenditure During Acute Periods of Sitting, Standing, and Walking. Difference in caloric expenditure in sitting versus standing desks. Regular activity breaks combined with physical activity improve postprandial plasma triglyceride, nonesterified fatty acid, and insulin responses in healthy, normal weight adults: A randomized crossover trial.
abstract: Overweight and obesity affects more than 66 % of the adult population and is associated with a variety of chronic diseases . Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies . Guidelines of the National Heart , Lung , and Blood Institute ( NHLBI ) encourage a 10 % reduction in weight , although considerable literature indicates reduction in health risk with 3 % to 5 % reduction in weight . Physical activity ( PA ) is recommended as a component of weight management for prevention of weight gain , for weight loss , and for prevention of weight regain after weight loss . In 2001 , the American College of Sports Medicine ( ACSM ) published a Position St and that recommended a minimum of 150 min wk(-1 ) of moderate-intensity PA for overweight and obese adults to improve health ; however , 200 - 300 min wk(-1 ) was recommended for long-term weight loss . More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss . To this end , we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain , for weight loss , and prevention of weight regain . Evidence supports moderate-intensity PA between 150 and 250 min wk(-1 ) to be effective to prevent weight gain .  Moderate-intensity PA between 150 and 250 min wk(-1 ) will provide only modest weight loss . Greater amounts of PA ( > 250 min wk(-1 ) ) have been associated with clinical ly significant weight loss .  Moderate-intensity PA between 150 and 250 min wk(-1 ) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction . Cross-sectional and prospect i ve studies indicate that after weight loss , weight maintenance is improved with PA > 250 min wk(-1 ) . However , no evidence from well- design ed r and omized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss .  Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk . Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk . There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain INTRODUCTION The aims of this prospect i ve cohort study were to examine 16-year trajectories of weight and BMI in young adult women who had a healthy BMI in 1996 and determinants of remaining in the healthy BMI category . METHODS A total of 4,881 women with healthy BMI at baseline and either healthy , overweight , or obese BMI at 16-year follow-up reported their weight , height , health , and health behaviors in six surveys of the Australian Longitudinal Study on Women 's Health between 1996 ( aged 18 - 23 years ) and 2012 ( aged 34 - 39 years ) . Determinants of BMI maintenance were estimated using binary logistic regression and generalized estimating equations in 2015 . RESULTS Almost 60 % remained in the healthy BMI category from 1996 to 2012 , ( mean weight gain , 0.19 kg/year ) , 29 % transitioned to overweight BMI ( 0.83 kg/year ) , and 11.6 % transitioned to obese ( 1.73 kg/year ) . The mean rates of annual weight gain in each group were consistent over time . Only three factors ( low alcohol , moderate/high physical activity , having a university degree ) were positively associated with maintaining a healthy BMI . Additional behavioral factors ( smoking , high sitting time , energy intake , dieting , takeaway food , and use of oral contraceptives ) , as well as blue collar occupation , separation/divorce/widowhood , and major illness were negatively associated with BMI maintenance . CONCLUSIONS To prevent the transition from healthy to overweight/obese BMI , weight gain must be limited to < 0.5 kg/year . Women with healthy BMI , but with higher rates of weight gain in their early 20s , could be identified by health professionals for assistance with prevention of becoming overweight/obese Background / Objectives : Despite considerable research on the association between physical activity ( PA ) and body composition , there remains limited information on the directionality of the relationship . The present study examined the prospect i ve associations among objective ly measured PA , energy intake ( EI ) and body composition . Subjects/ Methods : A convenience sample of 430 adults ( 49 % male ) between 21 and 35 years of age was followed over 1 year with repeated measurements taken every 3 months . BMI ( kg/m2 ) and percent body fat ( % BF ) were calculated based on anthropometric measurements and dual energy X-ray absorptiometry . A multi-sensor device was worn over a period of 10 days to estimate total daily energy expenditure and time spent in different intensities . EI was calculated based on change in body composition and total daily energy expenditure . Results : A total of 379 participants provided valid data . On average , participants experienced a significant weight gain of 1.2±4.3 kg during the 12-month observation period , which was associated with an increase in % BF ( 0.8±3.2 % ) . Average time spent in moderate-to-vigorous PA ( MVPA ) decreased significantly , whereas EI remained constant . Optimal linear mixed models , adjusting for age and sex , showed an inverse effect of MVPA on BMI and % BF , whereas EI only directly affected BMI ( P<0.001 ) . There was also a significant inverse effect of BMI and % BF on MVPA ( P<0.001 ) . Conclusions : Results of this study indicate an inverse reciprocal association between MVPA and measures of adiposity . Thus , primary preventive actions are warranted to avoid excess weight gain , which may result in a vicious cycle of weight gain and low PA 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 Aims Type 2 diabetes mellitus ( T2DM ) , a serious and prevalent chronic disease , is traditionally associated with older age . However , due to the rising rates of obesity and sedentary lifestyles , it is increasingly being diagnosed in the younger population . Sedentary ( sitting ) behaviour has been shown to be associated with greater risk of cardio-metabolic health outcomes , including T2DM . Little is known about effective interventions to reduce sedentary behaviour in younger adults at risk of T2DM . We aim ed to investigate , through a r and omised controlled trial ( RCT ) design , whether a group-based structured education workshop focused on sitting reduction , with self-monitoring , reduced sitting time . Methods Adults aged 18–40 years who were either overweight ( with an additional risk factor for T2DM ) or obese were recruited for the Sedentary Time ANd Diabetes ( ST AND ) RCT . The intervention programme comprised of a 3-hour group-based structured education workshop , use of a self-monitoring tool , and follow-up motivational phone call . Data were collected at three time points : baseline , 3 and 12 months after baseline . The primary outcome measure was accelerometer-assessed sedentary behaviour after 12 months . Secondary outcomes included other objective ( activPAL ) and self-reported measures of sedentary behaviour and physical activity , and biochemical , anthropometric , and psycho-social variables . Results 187 individuals ( 69 % female ; mean age 33 years ; mean BMI 35 kg/m2 ) were r and omised to intervention and control groups . 12 month data , when analysed using intention-to-treat analysis ( ITT ) and per- protocol analyses , showed no significant difference in the primary outcome variable , nor in the majority of the secondary outcome measures . Conclusions A structured education intervention design ed to reduce sitting in young adults at risk of T2DM was not successful in changing behaviour at 12 months . Lack of change may be due to the brief nature of such an intervention and lack of focus on environmental change . Moreover , some participants reported a focus on physical activity rather than reductions in sitting per se . The habitual nature of sedentary behaviour means that behaviour change is challenging . Trial Registration Controlled-Trials.com IS RCT Objective Evidence on the direction of the association between sitting time and obesity is limited . The prospect i ve associations between baseline total sitting time and subsequent changes in body mass index ( BMI ) , and baseline BMI and subsequent changes in sitting time were examined . Methods BMI , from self-reported height and weight , and a single-item  measure of sitting time  were ascertained at two time points ( 3.4 ± 0.96 years apart ) in a prospect i ve question naire-based cohort of 31,787 Australians aged 45–65 years without severe physical limitations . Results In a fully adjusted model , baseline obesity was associated with  increased sitting time among all participants ( adjusted odds ratio [ aOR ] = 1.20 [ 95 % CI , 1.11 - 1.30 ] ; P < 0.001 ) and in most subgroups . The association was significant among those who were sitting < 4 hours/day ( aOR = 1.24 [ 95 % CI , 1.07 - 1.44 ] ; P = 0.004 ) and 4–8 hours/day at baseline ( aOR=1.18 [ 95 % CI , 1.06 - 1.32 ] ; P = 0.003 ) , but not in the high sitting groups ( P = 0.111 and 0.188 for 8–11 and ≥11 sitting hours/day , respectively ) . Nonsignificant and inconsistent results were observed for the association between baseline sitting time and subsequent change in BMI . Conclusions Our findings support the hypothesis that obesity may lead to a  subsequent increase in total sitting time  , but the association in the other direction is unclear BACKGROUND Although it is known that abdominal obesity increases the risk of chronic diseases , prospect i ve data examining the relation between lifestyle factors and the accumulation of abdominal adipose tissue are sparse . OBJECTIVE The objective of the study was to determine the associations of changes in diet , physical activity , alcohol consumption , and smoking  with 9-y waist gain among US men . DESIGN A prospect i ve cohort comprised 16 587 US men aged 40 - 75 y at baseline in 1986 .  Data on  lifestyle factors  were provided periodically with the use of self-reported question naires , and participants measured and reported their waist circumference in 1987 and 1996 . RESULTS In multivariate analyses , a 2 % increment in energy intake from trans fats that were isocalorically substituted for either polyunsaturated fats or carbohydrates was significantly associated with a 0.77-cm waist gain over 9 y ( P < 0.001 for each comparison ) . An increase of 12 g total fiber/d was associated with a 0.63-cm decrease in waist circumference ( P < 0.001 ) , whereas smoking cessation and a 20-h/wk increase in television watching were associated with a 1.98-cm and 0.59-cm waist gain , respectively ( P < 0.001 ) . Increases of 25 metabolic equivalent tasks ( METs ) * h/wk in vigorous physical activity and of > /= 0.5 h/wk in weight training were associated with 0.38-cm and 0.91-cm decreases in waist circumference , respectively ( P < 0.001 for each comparison ) . These associations remained significant after further adjustment for concurrent change in body mass index . Changes in total fat and alcohol consumption and in walking volume were not significantly related to waist gain . CONCLUSIONS Waist gain may be modulated by changes in trans fat and fiber consumption , smoking cessation , and physical activity OBJECTIVE Observational studies show breaking up prolonged sitting has beneficial associations with cardiometabolic risk markers , but intervention studies are required to investigate causality . We examined the acute effects on postpr and ial glucose and insulin levels of uninterrupted sitting compared with sitting interrupted by brief bouts of light- or moderate-intensity walking . RESEARCH DESIGN AND METHODS Overweight/obese adults ( n = 19 ) , aged 45–65 years , were recruited for a r and omized three-period , three-treatment acute crossover trial : 1 ) uninterrupted sitting ; 2 ) seated with 2-min bouts of light-intensity walking every 20 min ; and 3 ) seated with 2-min bouts of moderate-intensity walking every 20 min . A st and ardized test drink was provided after an initial 2-h period of uninterrupted sitting . The positive incremental area under curves ( iAUC ) for glucose and insulin ( mean [ 95 % CI ] ) for the 5 h after the test drink ( 75 g glucose , 50 g fat ) were calculated for the respective treatments . RESULTS The glucose iAUC ( mmol/L ) ⋅ h after both activity-break conditions was reduced ( light : 5.2 [ 4.1–6.6 ] ; moderate : 4.9 [ 3.8–6.1 ] ; both P < 0.01 ) compared with uninterrupted sitting ( 6.9 [ 5.5–8.7 ] ) . Insulin iAUC ( pmol/L ) ⋅ h was also reduced with both activity-break conditions ( light : 633.6 [ 552.4–727.1 ] ; moderate : 637.6 [ 555.5–731.9 ] , P < 0.0001 ) compared with uninterrupted sitting ( 828.6 [ 722.0–950.9 ] ) . CONCLUSIONS Interrupting sitting time with short bouts of light- or moderate-intensity walking  lowers postpr and ial glucose and insulin levels  in overweight/obese adults . This may improve glucose metabolism and potentially be an important public health and clinical intervention strategy for reducing cardiovascular risk Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Background Prospect i ve studies report associations between indicators of time spent sitting and  obesity risk .  Most studies use a single indicator of sedentary behavior and are unable to clearly identify whether sedentary behavior is a cause or a consequence of obesity . Purpose To investigate cross-sectional and prospect i ve associations between multiple sitting time indicators and  obesity  and examine the possibility of reverse causality . Methods Using data from the Whitehall II cohort , multiple logistic models were fitted to examine associations between prevalent obesity ( BMI ≥30 ) at Phase 5 ( 1997–1999 ) , and incident obesity between Phases 5 and 7 ( 2003–2004 ) across four levels of five sitting exposures ( work sitting , TV viewing , non-TV leisure-time sitting , leisure-time sitting , and total sitting ) . Using obesity data from three prior phases ( 1985–1988 , 1991–1993 ; and recalled weight at age 25 years ) , linear regression models were fitted to examine the association between prior obesity and sitting time at Phase 5 . Analyses were conducted in 2012 . Results None of the sitting exposures were associated with obesity either cross-sectionally or prospect ively . Obesity at one previous measurement phase was associated with a 2.43-hour/week ( 95 % CI=0.07 , 4.78 ) increase in TV viewing ; obesity at three previous phases was associated with a 7.42-hour/week ( 95 % CI=2.7 , 12.46 ) increase in TV-viewing hours/week at Phase 5 . Conclusions Sitting time was not associated with obesity cross-sectionally or prospect ively . Prior obesity was prospect ively associated with time spent watching TV per week but not other types of sitting Objectives It is unclear whether sedentary behaviour , and the domain in which it occurs , is related to  body mass index ( BMI ) change . We aim to eluci date whether sedentary behaviour is prospect ively related to BMI change using markers from three domains ( leisure , work and commuting ) . Methods Among employed 1958 British birth cohort members ( n = 6,562 ) , we analysed whether TV-viewing , work sitting ( six categories : 0 h/d to > 4 h/d ) and motorised commuting ( at 45 y ) were related to BMI ( at 45 y and 50 y ) and BMI change 45–50 y , after adjusting for lifestyle and socioeconomic factors . Results Per category higher TV-viewing , 45 y and 50 y BMI were higher by 0.69 kg/m2 ( 95 % CI : 0.59,0.80 ) and 0.75 kg/m2 ( 0.64,0.86 ) respectively . A category higher TV-viewing was associated with 0.11 kg/m2 ( 0.06,0.17 ) increased BMI 45–50 y , attenuating to 0.06 kg/m2 ( 0.01,0.12 ) after adjustment . There was no trend for work sitting  with 45 y or 50 y BMI , nor , after adjustment , for BMI change . However , those sitting 2–3 h/d had greater BMI gain by 0.33 kg/m2 ( 0.10,0.56 ) compared to those sitting 0–1 h/d . Associations between TV-viewing and BMI change were independent of work sitting . Motorised commuting was associated with 45 y , but not 50 y BMI or change . Conclusions TV-viewing is associated with BMI gain in mid-adulthood ; evidence is weaker for other sedentary behaviours ABSTRACT Purpose Both moderate-to-vigorous physical activity ( MVPA ) and sedentary behavior can be associated with adult adiposity . Much of the relevant evidence is from cross-sectional studies or from prospect i ve studies with relevant exposure measures at a single time point before weight gain or incident obesity . This study examined whether changes in MVPA and television ( TV ) viewing time are associated with subsequent changes in waist circumference , using data from three separate observation points in a large population -based prospect i ve study of Australian adults . Methods Data were obtained from the Australian Diabetes , Obesity , and Lifestyle study collected in 1999–2000 ( baseline ) , 2004–2005 ( wave 2 ) , and 2011–2012 ( wave 3 ) . The study sample consisted of adults age 25 to 74 yr at baseline who also attended site measurement at three time points ( n = 3261 ) . Multilevel linear regression analysis examined associations of initial 5-yr changes in MVPA and TV viewing time ( from baseline to wave 2 ) with 12-yr change in waist circumference ( from baseline to wave 3 ) , adjusting for well-known confounders . Results As categorical predictors , increases in MVPA significantly attenuated increases in waist circumference ( P for trend < 0.001 ) . TV viewing time change was not significantly associated with changes in waist circumference ( P for trend = 0.06 ) . Combined categories of  MVPA and TV viewing time changes were predictive of waist circumference increases ; compared with those who increased MVPA and reduced TV viewing time , those who reduced MVPA and increased TV viewing time had a 2-cm greater increase in waist circumference ( P = 0.001 ) . Conclusion Decreasing MVPA emerged as a significant predictor of increases in waist circumference . Increasing TV viewing time was also influential , but its impact was much weaker than MVPA OBJECTIVE : Since the prevalence of adult obesity is increasing in the United States , we examined the effect of changing common habits ( exercise , TV viewing , smoking and eating habits ) on four year change in body weight . DESIGN : A prospect i ve cohort study of US male health professionals with follow-up from 1988–1992 . Participants were 19 478 men aged 40–75 in 1986 , who were free of cancer , coronary heart disease , stroke and diabetes . METHODS : Multiple regression was used to determine the association between four year change in body weight ( from 1988–1992 ) and common habits , after adjusting for baseline age , hypertension and hypercholesterolemia . RESULTS : For middle aged men , vigorous activity was associated with weight reduction and TV/VCR viewing and eating between meals with weight gain . Quitting smoking and a history of voluntary weight loss prior to the study period were consistently related to weight increase . Recently being on a diet was more strongly associated with weight loss among older men . Over the four year follow-up period , middle-aged men who increased their exercise  , decreased  TV viewing  and stopped eating between meals  , lost an average weight of −1.4 kg ( 95 % confidence interval (CI)−1.6 – −1.1 kg ) , compared to a weight gain of 1.4 kg among the overall population . The prevalence of obesity  among middle-aged men was lowest among those who maintained a relatively high level of vigorous physical activity , compared to those who were relatively sedentary . CONCLUSION : These data suggest that improvement in the mix of health habits , particularly increasing vigorous activity , as well as decreasing TV use and changing eating habits , results in weight maintenance or a modest weight loss over four years OBJECTIVE : To examine long-term effects of leisure time physical activity ( ltpa ) and occupational physical activity ( opa ) on later obesity , and to examine the effect of body weight on later physical inactivity in men with and without juvenile onset obesity . DESIGN : Population -based longitudinal study of obese and nonobese men , who were identified as draftees of median age of 19 y in 1943–77 and later examined at general health surveys in 1982–84 , and in 1991–93 . SETTING : Copenhagen and adjacent regions , Denmark . PARTICIPANTS : In all , 1143 juvenile obese men with a BMI ≥31 kg/m2 ( corresponding to 35 % overweight by an originally used national st and ard ) at draft board examination , and , as a nonobese control group , 1278 men selected as a 0.5 % r and om sample of the approximately 255 600 men examined at the draft board and thus representing the study population .MAIN OUTCOME MEASURES : Obesity , defined as BMI ≥30 kg/m2 , and physical inactivity at the last survey . RESULTS : In the cross-sectional analyses , there were strong concurrent inverse associations between ltpa and prevalence of obesity in both groups , whereas there was no relation to opa . In logistic regression analyses of obesity at the last survey , including both ltpa and opa as well as age , BMI at draft board examination , BMI at first follow-up , length of education , smoking and drinking habits , there were no significant effects of ltpa and opa on the risk of development of obesity in the nonobese group or maintenance of obesity in the obese group . Similar analyses of physical inactivity at the last follow-up as outcome showed a significant direct effect of BMI at first follow-up , with a significant trend in the nonobese group , but not in the obese group and no effects on opa . CONCLUSION : There is no long-term influence of physical activity on development and maintenance of obesity  in men , whereas greater body weight increases risk of later physical inactivity during leisure time OBJECTIVE To examine the role of television ( TV ) viewing in long-term maintenance of weight loss . RESEARCH METHODS AND PROCEDURES All subjects ( N = 1422 ) were enrolled in the National Weight Control Registry ( NWCR ) , a national sample of adults who have maintained a minimum weight loss of 13.6 kg for at least 1 year . Participants self-reported the average number of hours of weekly TV viewing at entry into the NWCR and at a 1-year follow-up . Cross-sectional and prospect i ve analyses were performed to determine the frequency of TV viewing  and the extent to which TV viewing was independently associated with weight regain over the 1-year of follow-up . RESULTS A relatively high proportion ( 62.3 % ) of participants reported watching 10 or fewer hours of TV per week on entry in the NWCR . More than one third of the sample ( 36.1 % ) reported watching < 5 h/wk , whereas only 12.4 % watched > or = 21 h/wk , which contrasts markedly from the national average of 28 hours of TV viewing per week reported by American adults . Both baseline TV viewing ( p < or = 0.02 ) and increases in TV viewing ( p < or = 0.001 ) over the follow-up were significant predictors of 1-year weight regain , independent of physical activity and dietary behaviors . DISCUSSION Individuals who are successful at maintaining weight loss over the long term are likely to spend a relatively minimal amount of time watching TV OBJECTIVE To determine whether interrupting prolonged sitting with brief bouts of light-intensity walking ( LW ) or simple resistance activities ( SRA ) improves postpr and ial cardiometabolic risk markers in adults with type 2 diabetes ( T2D ) . RESEARCH DESIGN AND METHODS In a r and omized crossover trial , 24 inactive overweight/obese adults with T2D ( 14 men 62 ± 6 years old ) underwent the following 8-h conditions on three separate days ( with 6–14 days washout ) : uninterrupted sitting ( control ) ( SIT ) , sitting plus 3-min bouts of LW ( 3.2 km · h−1 ) every 30 min , and sitting plus 3-min bouts of SRA ( half-squats , calf raises , gluteal contractions , and knee raises ) every 30 min . St and ardized meals were consumed during each condition . Incremental areas under the curve ( iAUCs ) for glucose , insulin , C-peptide , and triglycerides were compared between conditions . RESULTS Compared with SIT , both activity-break conditions significantly attenuated iAUCs for glucose ( SIT mean 24.2 mmol · h · L−1 [ 95 % CI 20.4–28.0 ] vs. LW 14.8 [ 11.0–18.6 ] and SRA 14.7 [ 10.9–18.5 ] ) , insulin ( SIT 3,293 pmol · h · L−1 [ 2,887–3,700 ] vs. LW 2,104 [ 1,696–2,511 ] and SRA 2,066 [ 1,660–2,473 ] ) , and C-peptide ( SIT 15,641 pmol · h · L−1 [ 14,353–16,929 ] vs. LW 11,504 [ 10,209–12,799 ] and SRA 11,012 [ 9,723–12,301 ] ) ( all P < 0.001 ) . The iAUC for triglycerides was significantly attenuated for SRA ( P < 0.001 ) but not for LW ( SIT 4.8 mmol · h · L−1 [ 3.6–6.0 ] vs. LW 4.0 [ 2.8–5.1 ] and SRA 2.9 [ 1.7–4.1 ] ) . CONCLUSIONS  Interrupting prolonged sitting with brief bouts of LW or SRA  attenuates acute postpr and ial glucose , insulin , C-peptide , and triglyceride responses in adults with T2D . With poor adherence to structured exercise , this approach is potentially beneficial and practical CONTEXT Current public health campaigns to reduce obesity and type 2 diabetes have largely focused on increasing exercise , but have paid little attention to the reduction of sedentary behaviors . OBJECTIVE To examine the relationship between various sedentary behaviors , especially prolonged television ( TV ) watching , and risk of obesity and type 2 diabetes in women . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study conducted from 1992 to 1998 among women from 11 states in the Nurses ' Health Study . The obesity analysis included 50 277 women who had a body mass index ( BMI ) of less than 30 and were free from diagnosed cardiovascular disease , diabetes , or cancer and completed questions on physical activity and sedentary behaviors at baseline . The diabetes analysis included 68 497 women who at baseline were free from diagnosed diabetes mellitus , cardiovascular disease , or cancer . MAIN OUTCOME MEASURES Onset of obesity and type 2 diabetes mellitus . RESULTS During 6 years of follow-up , 3757 ( 7.5 % ) of 50 277 women who had a BMI of less than 30 in 1992 became obese ( BMI > or = 30 ) . Overall , we documented 1515 new cases of type 2 diabetes .  Time spent watching TV was positively associated with risk of obesity and type 2 diabetes . In the multivariate analyses adjusting for age , smoking , exercise levels , dietary factors , and other covariates , each 2-h/d increment in TV watching was associated with a 23 % ( 95 % confidence interval [ CI ] , 17%-30 % ) increase in obesity and a 14 % ( 95 % CI , 5%-23 % ) increase in risk of diabetes ; each 2-h/d increment in sitting at work was associated with a 5 % ( 95 % CI , 0%-10 % ) increase in obesity and a 7 % ( 95 % CI , 0%-16 % ) increase in diabetes . In contrast , st and ing or walking around at home ( 2 h/d ) was associated with a 9 % ( 95 % CI , 6%-12 % ) reduction in obesity and a 12 % ( 95 % CI , 7%-16 % ) reduction in diabetes . Each 1 hour per day of brisk walking was associated with a 24 % ( 95 % CI , 19%-29 % ) reduction in obesity and a 34 % ( 95 % CI , 27%-41 % ) reduction in diabetes . We estimated that in our cohort , 30 % ( 95 % CI , 24%-36 % ) of new cases of obesity and 43 % ( 95 % CI , 32%-52 % ) of new cases of diabetes could be prevented by adopting a relatively active lifestyle ( < 10 h/wk of TV watching and > or = 30 min/d of brisk walking ) . CONCLUSIONS Independent of exercise levels , sedentary behaviors , especially TV watching , were associated with significantly elevated risk of obesity and type 2 diabetes , whereas even light to moderate activity was associated with substantially lower risk . This study emphasizes the importance of reducing prolonged TV watching and other sedentary behaviors for preventing obesity and diabetes OBJECTIVE Sedentary behaviour may be a contributor to weight gain in today 's young adult women , who are gaining weight faster than women in their mothers ' generation . The aim was to examine the relationships between sitting time and weight in young women . METHOD Data were from women born in 1973 - 1978 who completed surveys in 2000 , 2003 and 2006 for the Australian Longitudinal Study on Women 's Health . Associations between concurrent changes in sitting-time and weight , and prospect i ve associations between these variables , were examined using ANOVA and linear regressions , stratified by BMI -category in 2000 ( n=5562 ) . RESULTS Among overweight and obese women , percentage weight change from 2000 to 2006 was higher in those whose  sitting time  increased ( > 20 % ) than in those whose sitting time decreased ( > 20 % ) over the same period ( p<0.05 ) . Conversely , percentage change in sitting time was significantly higher in those who gained weight ( > 5 % ) than in those who lost weight ( > 5 % ) ( p<0.05 ) . There were no prospect i ve associations between ( change in )  sitting time and weight change , or between ( change in ) weight and change in sitting time . CONCLUSION The results confirm associations between concurrent changes in weight and changes in sitting time  in overweight and obese women , but no prospect i ve relationships were found BACKGROUND Identifying strategies to increase energy expenditure ( EE ) may help combat the harmful effects of sedentary behavior . This study examined EE during  sitting , st and ing  , and walking . METHODS Participants ( N = 74 ) were r and omized to 2 of the following activities :  sitting using a laptop computer ( SIT-C ) , sitting watching television ( SIT-T ) , st and ing watching television ( ST AND ) , and walking at a self-selected pace ≤3.0 ( mph ) ( WALK ) . Each activity lasted 15 minutes with a 3-minute transition period between activities . The experimental conditions were : SIT-C to ST AND ( N = 18 ) , SIT-T to WALK ( N = 18 ) , ST AND to SIT-C ( N = 20 ) , and WALK to SIT-T ( N = 18 ) . EE was measured using indirect calorimetry . RESULTS Based on the first activity performed , EE during WALK ( 55.92 ± 14.19 kcal ) was significantly greater than SIT-C ( 19.63 ± 6.90 kcal ) , SIT-T ( 18.66 ± 4.01 kcal ) , and ST AND ( 21.92 ± 5.08 kcal ) ( P < .001 ) . Cumulative EE in SIT-T to WALK ( 74.50 ± 17.88 kcal ) and WALK to SIT-T ( 82.72 ± 21.70 kcal ) was significantly greater than EE in SIT-C to ST AND ( 45.38 ± 14.78 kcal ) and ST AND to SIT-C ( 45.64 ± 9.69 kcal ) ( P < .001 ) . CONCLUSION Substituting periods of sitting or st and ing with walking significantly increases EE , but substituting periods of sitting with st and ing may not affect EE . Thus , the potential benefits of st and ing as opposed to sitting need further investigation beyond the role of EE BACKGROUND Traditional desks require students to sit ; however , recently schools have provided students with nontraditional st and ing desks . The purpose of this study was to investigate differences in caloric expenditure of young adults while sitting at a st and ard classroom desk and st and ing at a nontraditional st and ing classroom desk . METHODS Twenty ( 10 male/10 female ) young ( 22.8 ± 1.9 y ) , healthy participants reported to the laboratory between the hours of 7:00 AM and 2:00 PM following a 12-h fast and 48-h break in exercise . Participants were r and omly assigned to perform a series of mathematical problems either sitting at a normal classroom desk or st and ing at a nontraditional st and ing desk . Inspired and expired gases were collected for 45-min for the determination of oxygen consumption ( VO2 ) , carbon dioxide production ( VCO2 ) , and minute ventilation ( VE ) using a metabolic gas system . RESULTS There were significant increases from sitting to st and ing in VO2 ( 0.22 ± 0.05 vs. 0.28 ± 0.05 L·min-1 , P ≤ .0001 ) , VCO2 ( 0.18 ± 0.05 vs. 0.24 ± 0.050 L·min-1 , P ≤ .0001 ) , VE ( 7.72 ± 0.67 vs. 9.41 ± 1.20 L·min-1 , P ≤ .0001 ) , and kilocalories expended per minute ( 1.36 ± 0.20 kcal/min , P ≤ .0001 vs. 1.02 ± 0.22 kcal/min , P ≤ .0001 ) . CONCLUSIONS Results indicate a significant increase in caloric expenditure in subjects that were st and ing at a st and ing classroom desk compared with sitting at a st and ard classroom desk BACKGROUND Compared with prolonged sitting , regular activity breaks immediately lower postpr and ial glucose and insulin , but not triglyceride responses . Postpr and ial triglycerides can be lowered by physical activity but the effect is often delayed by ∼12 to 24 hours . OBJECTIVE The objective of the study was to determine whether regular activity breaks affect postpr and ial triglyceride response in a delayed manner similar to physical activity . METHODS In a r and omized crossover trial , 36 adults ( body mass index 23.9 kg/m2 [ st and ard deviation 3.9 ] ) completed four 2-day interventions : ( 1 ) prolonged sitting ( SIT ) ; ( 2 ) prolonged sitting with 30 minutes of continuous walking ( 60 % VO2max ) , at the end of Day 1 ( SIT + PAD1 ) ; ( 3 ) Sitting with 2 minutes of walking ( 60 % VO2max ) every 30 minutes ( RAB ) ; ( 4 ) A combination of the continuous walking and regular activity breaks in 2 and 3 above ( RAB + PAD1 ) . Postpr and ial plasma triglyceride , nonesterified fatty acids , glucose , and insulin responses were measured in venous blood over 5 hours on Day 2 . RESULTS Compared with SIT , both RAB ( difference : -43.61 mg/dL·5 hours ; 95 % confidence interval [ CI ] -83.66 to -2.67 ; P = .035 ) and RAB + PAD1 ( -65.86 mg/dL·5 hours ; 95 % CI -112.14 to -19.58 ; P = .005 ) attenuated triglyceride total area under the curve ( tAUC ) . RAB + PAD1 produced the greatest reductions in insulin tAUC ( -23 % ; 95 % CI -12 % to -31 % ; P < .001 ) , whereas RAB result ed in the largest increase in nonesterified fatty acids ( tAUC , 10.08 mg/dL·5 hours ; 95 % CI 5.60 - 14.84 ; P < .001 ) . There was no effect on glucose tAUC ( P = .290 ) . CONCLUSIONS Postpr and ial triglyceride response is attenuated by regular activity breaks , when measured ∼24 hours after breaks begin . Combining regular activity breaks with 30 minutes of continuous walking further improves insulinemic and lipidemic responses
target: Conclusions Meta- analysis of data from prospect i ve cohort studies showed small , inconsistent and non-significant associations between sedentary behavior and body weight
background: Background The cumulative effect of too much sedentary behavior may contribute to  weight gain and obesity .
  Objective The aim of this study was to conduct a systematic review and meta- analysis of prospect i ve cohorts and r and omized controlled studies to determine the association between sedentary  behavior  and body weight and obesity in adults .