ObjectiveTo examine the overall effectiveness of interventions for reducing adult sedentary behaviour and to directly compare environmental, behavioural and multicomponent interventions.DesignIntervention systematic review with meta-analysis.Data sourcesOvid PsycINFO, Ovid MEDLINE, EBSCOHost CINAHL, EBSCOHost SPORTDiscus and PubMed were searched from inception to 26 July 2017.Eligibility criteriaTrials including randomised controlled trials, quasi-randomised, cluster-randomised, parallel group, prepost, factorial and crossover trials where the primary aim was to change the sedentary behaviour of healthy adults assessed by self-report (eg, questionnaires, logs) or objective measures (eg, accelerometry).ResultsThirty-eight trials of 5983 participants published between 2003 and 2017 were included in the qualitative synthesis; 35 studies were included in the quantitative analysis (meta-analysis). The pooled effect was a significant reduction in daily sitting time of −30.37 min/day (95% CI −40.86 to −19.89) favouring the intervention group. Reductions in sitting time were similar between workplace (−29.96 min/day; 95% CI −44.05 to –15.87) and other settings (−30.47 min/day; 95% CI −44.68 to –16.26), which included community, domestic and recreational environments. Environmental interventions had the largest reduction in daily sitting time (−40.59 min/day; 95% CI −61.65 to –19.53), followed by multicomponent (−35.53 min/day; 95% CI −57.27 to –13.79) and behavioural (−23.87 min/day; 95% CI −37.24 to –10.49) interventions.ConclusionInterventions targeting adult sedentary behaviour reduced daily sitting time by an average of 30 min/day, which was likely clinically meaningful.

Adults working in academic occupations are at risk for exposure to sedentary behaviours. The aim of this study was to determine the influence of an educational video on viewer's health beliefs and sedentary behaviours. Data was collected between March and April 2017 from healthy adults employed in an academic institution in Ontario, Canada (n=71; age= 40.0±12.1 y) using a single-group, pre-post design. Evidence-based strategies to reduce sedentary behaviour at home and at work were summarized and presented as cues to action in a 5-minute video. Self-reported physical activity, sedentary behaviours, health beliefs, and readiness to change were measured using the International Physical Activity Questionnaire, Sedentary behaviour Health Belief Questionnaire, and Readiness Ruler, respectively, one week before (T1), immediately after (T2), and one week after watching the video (T3). Occupational and leisure-time sitting time was assessed daily via participant log. Participants reduced weekday and weekend sitting time by-35.9 minutes/day (p=0.03) and-21.1 minutes/day (p=0.01), respectively. Readiness to change increased between T2 and T3 (p=0.004). Perceived severity of (p=0.03) and susceptibility to (p=0.01) the health risks associated with sedentary behaviour increased from T1 to T2. Perceived benefit scores (r s =-0.25, p=0.04) at T2 were inversely associated with reductions in sitting time from T2 to T3. It is possible that exposure to the video influenced several health benefits constructs and reduced daily sitting time in healthy adults working in academic occupations.