School-based interventions are promising for targeting a change in obesity-related behaviours in children. However, the efficacy of school-based interventions to prevent obesity remains unclear. This review examined the effectiveness of school-based interventions at changing obesity-related behaviours (increased physical activity, decreased sedentary behaviour and improved nutrition behaviour) and/or a change in BMI/BMI z-score. Following PRISMA guidelines, seven databases were systematically searched from 1 January 2009 to 31 December 2020. Two review authors independently screened studies for eligibility, completed data extraction and assessed the risk of bias of each of the included studies. Forty-eight studies met the inclusion criteria and were included in a narrative synthesis. Thirty-eight studies were eligible for inclusion in a meta-analysis. The findings demonstrate that interventions in children when compared to controls resulted in a small positive treatment effect in the control group (2.14; 95% CI = 0.77, 3.50). There was no significant effect on sedentary behaviour, energy intake and fruit and vegetable intake. Significant reductions were found between groups in BMI kg/m² (−0.39; 95% CI = −0.47, −0.30) and BMI z-score (−0.05; 95% CI = −0.08, −0.02) in favour of the intervention. The findings have important implications for future intervention research in terms of the effectiveness of intervention components and characteristics.

The present study aimed to assess the association between sedentary behavior and sarcopenia among adults aged ≥65 years. Cross-sectional data from the Study on Global Ageing and Adult Health were analyzed. Sarcopenia was defined as having low skeletal muscle mass and either a slow gait speed or a weak handgrip strength. Self-reported sedentary behavior was assessed as a continuous variable (hours per day) and also as a categorical variable (0–<4, 4–<8, 8–<11, ≥11 hours/day). Multivariable logistic regression was conducted to assess the association between sedentary behavior and sarcopenia. Analyses using the overall sample and country-wise samples were conducted. A total of 14,585 participants aged ≥65 years were included in the analysis. Their mean age was 72.6 (standard deviation, 11.5) years and 55% were females. Compared to sedentary behavior of 0–<4 hours/day, ≥11 hours/day was significantly associated with 2.14 (95% CI = 1.06–4.33) times higher odds for sarcopenia. The country-wise analysis showed that overall, a one-hour increase in sedentary behavior per day was associated with 1.06 (95% CI = 1.04–1.10) times higher odds for sarcopenia, while the level of between-country heterogeneity was low (I² = 12.9%). Public health and healthcare practitioners may wish to target reductions in sedentary behavior to aid in the prevention of sarcopenia in older adults.

Physical activity is an important determinant of health in later life. The public health restrictions in response to COVID-19 have interrupted habitual physical activity behaviours in older adults. In response, numerous exercise programmes have been developed for older adults, many involving chair-based exercise. The aim of this systematic review was to synthesise the effects of chair-based exercise on the health of older adults. Ovid Medline, EMBASE, CINAHL, AMED, PyscInfo and SPORTDiscus databases were searched from inception to 1 April 2020. Chair-based exercise programmes in adults ≥50 years, lasting for at least 2 weeks and measuring the impact on physical function were included. Risk of bias of included studies were assessed using Cochrane risk of bias tool v2. Intervention content was described using TiDieR Criteria. Where sufficient studies (≥3 studies) reported data on an outcome, a random effects meta-analysis was performed. In total, 25 studies were included, with 19 studies in the meta-analyses. Seventeen studies had a low risk of bias and five had a high risk of bias. In this systematic review including 1388 participants, results demonstrated that chair-based exercise programmes improve upper extremity (handgrip strength: MD = 2.10; 95% CI = 0.76, 3.43 and 30 s arm curl test: MD = 2.82; 95% CI = 1.34, 4.31) and lower extremity function (30 s chair stand: MD 2.25; 95% CI = 0.64, 3.86). The findings suggest that chair-based exercises are effective and should be promoted as simple and easily implemented activities to maintain and develop strength for older adults.

Background: Evidence suggests that sedentary behaviour (SB) is associated with poor health outcomes. SB at any age may have significant consequences for health and well-being and interventions targeting SB are accumulating. Therefore, the need to review the effects of multicomponent, complex interventions that incorporate effective strategies to reduce SB are essential. Methods: A systematic review and meta-analysis were conducted investigating the impact of interventions targeting SB across the lifespan. Six databases were searched and two review authors independently screened studies for eligibility, completed data extraction and assessed the risk of bias and complexity of each of the included studies. Results: A total of 77 adult studies (n=62, RCTs) and 84 studies (n=62, RCTs) in children were included. The findings demonstrated that interventions in adults when compared to active controls resulted in non-significant reductions in SB, although when compared to inactive controls significant reductions were found in both the short (MD -56.86; 95%CI -74.10, -39.63; n=4632; I2 83%) and medium-to-long term (MD -20.14; 95%CI -34.13, -6.16; n=4537; I2 65%). The findings demonstrated that interventions in children when compared to active controls may lead to relevant reductions in daily sedentary time in the short-term (MD -59.90; 95%CI -102.16, -17.65; n=267; I2 86%), while interventions in children when compared to inactive controls may lead to relevant reductions in the short-term (MD -25.86; 95%CI -40.77, -10.96; n=9480; I2 98%) and medium-to-long term (MD -14.02; 95%CI -19.49, -8.55; n=41,138; I2 98%). The assessment of complexity suggested that interventions may need to be suitably complex to address the challenges of a complex behaviour such as SB, but demonstrated that a higher complexity score is not necessarily associated with better outcomes in terms of sustained long-term changes. Conclusions： Interventions targeting reductions in SB have been shown to be successful, especially environmental interventions in both children and adults. More needs to be known about how best to optimise intervention effects. Future intervention studies should apply more rigorous methods to improve research quality, considering larger sample sizes, randomised controlled designs and valid and reliable measures of SB.

Introduction: Regular moderate‐to‐vigorous physical activity (MVPA) is associated with improved mental health, but the evidence for the effect of reducing sedentary behavior (SB) or increasing light PA (LPA) in older adults is lacking. Using isotemporal substitution (IS) models, the aim of this paper was to investigate the effect of substituting SB with LPA or MVPA on associations with mental health in older adults.Methods: Data from 1360 older adults (mean age 75.18 years) in four countries were utilized. PA and SB was measured using ActiGraph wGT3X‐BT + accelerometers worn for 7 days. Self‐rated mental health was measured using the Hospital and Anxiety Depression Scale (HADS). IS models estimated cross‐sectional associations when 30 minutes of one behavior was substituted with another. Models were adjusted for age, sex, marital status, and educational attainment.Results: Substituting 30 minutes of SB with LPA (β −.37; 95% CI −0.42, −0.32) or MVPA (β −.14; 95% CI −0.21, −0.07) and substituting LPA with MVPA (β −.11; 95% CI −0.18, −0.04) were associated with improvements in anxiety. However, substituting 30 minutes of SB with LPA (β .55; 95% CI 0.49, 0.62) was associated with increased depression.Conclusion: Replacing 30 minutes of SB with LPA or MVPA was associated with improved anxiety symptoms in older adults. Greater benefits were observed when shifting SB and LPA to MVPA.