Objective To examine the dose-response associations between accelerometer assessed total physical activity, different intensities of physical activity, and sedentary time and all cause mortality. Design Systematic review and harmonised meta-analysis. Data sources PubMed, PsycINFO, Embase, Web of Science, Sport Discus from inception to 31 July 2018. Eligibility criteria Prospective cohort studies assessing physical activity and sedentary time by accelerometry and associations with all cause mortality and reported effect estimates as hazard ratios, odds ratios, or relative risks with 95% confidence intervals. Data extraction and analysis Guidelines for meta-analyses and systematic reviews for observational studies and PRISMA guidelines were followed. Two authors independently screened the titles and abstracts. One author performed a full text review and another extracted the data. Two authors independently assessed the risk of bias. Individual level participant data were harmonised and analysed at study level. Data on physical activity were categorised by quarters at study level, and study specific associations with all cause mortality were analysed using Cox proportional hazards regression analyses. Study specific results were summarised using random effects meta-analysis. Main outcome measure All cause mortality. Results 39 studies were retrieved for full text review; 10 were eligible for inclusion, three were excluded owing to harmonisation challenges (eg, wrist placement of the accelerometer), and one study did not participate. Two additional studies with unpublished mortality data were also included. Thus, individual level data from eight studies (n=36 383; mean age 62.6 years; 72.8% women), with median follow-up of 5.8 years (range 3.0-14.5 years) and 2149 (5.9%) deaths were analysed. Any physical activity, regardless of intensity, was associated with lower risk of mortality, with a non-linear dose-response. Hazards ratios for mortality were 1.00 (referent) in the first quarter (least active), 0.48 (95% confidence interval 0.43 to 0.54) in the second quarter, 0.34 (0.26 to 0.45) in the third quarter, and 0.27 (0.23 to 0.32) in the fourth quarter (most active). Corresponding hazards ratios for light physical activity were 1.00, 0.60 (0.54 to 0.68), 0.44 (0.38 to 0.51), and 0.38 (0.28 to 0.51), and for moderate-to-vigorous physical activity were 1.00, 0.64 (0.55 to 0.74), 0.55 (0.40 to 0.74), and 0.52 (0.43 to 0.61). For sedentary time, hazards ratios were 1.00 (referent; least sedentary), 1.28 (1.09 to 1.51), 1.71 (1.36 to 2.15), and 2.63 (1.94 to 3.56). Conclusion Higher levels of total physical activity, at any intensity, and less time spent sedentary, are associated with substantially reduced risk for premature mortality, with evidence of a non-linear dose-response pattern in middle aged and older adults. Systematic review registration PROSPERO CRD42018091808.

Objectives To examine the joint associations of accelerometer-measured physical activity and sedentary time with all-cause mortality. Methods We conducted a harmonised meta-analysis including nine prospective cohort studies from four countries. 44 370 men and women were followed for 4.0 to 14.5 years during which 3451 participants died (7.8% mortality rate). Associations between different combinations of moderate-to-vigorous intensity physical activity (MVPA) and sedentary time were analysed at study level using Cox proportional hazards regression analysis and summarised using random effects meta-analysis. Results Across cohorts, the average time spent sedentary ranged from 8.5 hours/day to 10.5 hours/day and 8 min/day to 35 min/day for MVPA. Compared with the referent group (highest physical activity/lowest sedentary time), the risk of death increased with lower levels of MVPA and greater amounts of sedentary time. Among those in the highest third of MVPA, the risk of death was not statistically different from the referent for those in the middle (16%; 95% CI 0.87% to 1.54%) and highest (40%; 95% CI 0.87% to 2.26%) thirds of sedentary time. Those in the lowest third of MVPA had a greater risk of death in all combinations with sedentary time; 65% (95% CI 1.25% to 2.19%), 65% (95% CI 1.24% to 2.21%) and 263% (95% CI 1.93% to 3.57%), respectively. Conclusion Higher sedentary time is associated with higher mortality in less active individuals when measured by accelerometry. About 30–40 min of MVPA per day attenuate the association between sedentary time and risk of death, which is lower than previous estimates from self-reported data.

Background: Sedentary behavior is associated with health risks in adults. The potential benefits of reducing sedentary time may be dependent not only on decrease per se, but also on the type of activity it replaces. Few longitudinal studies have investigated the effects on mortality when replacing objectively assessed sedentary time with another physical activity (PA) behavior. Objective: To investigate the effects of replacing objectively assessed sedentary time with time in light-intensity PA or moderate-vigorous PA (MVPA) on all-cause mortality, cardiovascular disease (CVD) mortality or cancer mortality in a cohort with 15 years follow-up time. Methods: In total, 851 women and men from the population-based Sweden Attitude Behaviour and Change study were included. Time spent sedentary, in light-intensity PA and in MVPA were assessed using an Actigraph 7164 accelerometer. Mortality data were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI) and isotemporal substitution models were used to estimate the effect of replacing sedentary behavior with PA for the same amount of time. Results: Over a follow-up of 14.2 years (SD 1.9) with 12,117 person-years at risk, 79 deaths occurred, 24 deaths from CVD, 27 from cancer, and 28 from other causes. Replacing 30 minutes/day of sedentary time with light-intensity PA was associated with significant reduction in all-cause mortality risk (HR: 0.89, 95% CI: 0.81-0.98) and CVD mortality risk (HR: 0.76, 95% CI: 0.63-0.92). Replacing 10 minutes of sedentary time with MVPA was associated with reduction in CVD mortality risk (HR: 0.62, 95% CI: 0.42-0.91). No statistically significant reductions were found for cancer mortality. Conclusion: This statistical modelling study suggests that replacing sedentary time with light-intensity PA could have beneficial effect on both all-cause mortality and CVD mortality. Replacing sedentary time with MVPA could reduce CVD mortality.

Background: Prolonged sitting time is a risk factor for chronic disease, yet recent global surveillance is not well described. The aims were to clarify: (i) the countries that have collected country-level data on self-reported sitting time; (ii) the single-item tools used to collect these data; and (iii) the duration of sitting time reported across low- to high-income countries. Methods: Country-level data collected within the last 10 years using single-item self-report were included. The six-stage methodology: (1) reviewing Global Observatory for Physical Activity! Country Cards; (2–4) country-specific searches of PubMed, the Demographic and Health Survey website and Google; (5) analysing the Eurobarometer 88.4; and (6) country-specific searches for World Health Organization STEPwise reports. Results: A total of 7641 records were identified and screened for eligibility. Sixty-two countries (29%) reported sitting time representing 47% of the global adult population. The majority of data were from high-income (61%) and middle income (29%) countries. The tools used were the International Physical Activity Questionnaire (IPAQ; n = 34), a modified IPAQ (n = 1) or the Global Physical Activity Questionnaire (GPAQ; n = 27). The median of mean daily sitting times was 4.7 (IQR: 3.5–5.1) hours across all countries. Higher-income countries recorded a longer duration of sitting time than lower-income countries (4.9 vs 2.7 h). Conclusions: This study provides an updated collation of countries collecting self-reported sitting time data. The daily sitting time findings should be interpreted cautiously. Current surveillance of sitting time is limited by a lack of coverage. Measures of population sitting time that are valid, feasible and sensitive to change should be embedded within global surveillance systems, to help guide future policy, research and practice. Trial registration: Not applicable.

Objective: To give the rationale and evidence for and a detailed description of a rehabilitation programme of proven effectiveness in improving balance in older adults. Background theory and evidence: Based on the knowledge that balance loss usually occurs in situations when attention is divided, especially when being older, and that balance control relies on the interaction of several physiological systems, we have developed a specific and progressive balance training programme with dual- and multi-task exercises for older adults. Practical application: Balance demanding exercises, specific to the various components of balance control and to situations in daily life, were performed in sitting, standing and walking at three different levels of progression (basic, moderate and advanced) of increasing difficulty and complexity. The training was performed in 45-minutes group sessions, with 6–10 participants in each group, three times per week during 12 weeks, with two or three physiotherapists present. Conclusions: This balance training programme strengthens self-efficacy in balance control leading to improved fall-related self-efficacy, reduced fear of falling, increased walking speed, and improved physical function. Participants found the programme motivating, valuable, fun, and enjoyable, which was reflected in a high attendance rate.