Despite the rapid increase in evidence from the past decade on daily steps and health-related outcomes, existing systematic reviews primarily focused on few outcomes, such as all-cause mortality. This study synthesised the prospective dose-response relationship between daily steps and health outcomes including all-cause mortality, cardiovascular disease, cancer, type 2 diabetes, cognitive outcomes, mental health outcomes, physical function, and falls. For this systematic review and meta-analysis, we searched PubMed and EBSCO CINAHL for literature published between Jan 1, 2014, and Feb 14, 2025, supplemented by other search strategies. Eligible prospective studies examined the relationship between device-measured daily steps and health outcomes among adults without restrictions on language or publication type. Pairs of reviewers (BN, KO, ML, and TN) independently did the study selection, data extraction, and risk of bias assessment using the 9-point Newcastle-Ottawa Scale. Hazard ratios (HRs) from individual studies were synthesised using random-effects dose-response meta-analysis where possible. Certainty of evidence was assessed using GRADE. This trial is registered with PROSPERO (CRD42024529706). 57 studies from 35 cohorts were included in the systematic review and 31 studies from 24 cohorts were included in meta-analyses. For all-cause mortality, cardiovascular disease incidence, dementia, and falls, an inverse non-linear dose-response association was found, with inflection points at around 5000-7000 steps per day. An inverse linear association was found for cardiovascular disease mortality, cancer incidence, cancer mortality, type 2 diabetes incidence, and depressive symptoms. Based on our meta-analyses, compared with 2000 steps per day, 7000 steps per day was associated with a 47% lower risk of all-cause mortality (HR 0·53 [95% CI 0·46-0·60]; I²=36·3; 14 studies), a 25% lower risk of cardiovascular disease incidence (HR 0·75 [0·67-0·85]; I²=38·3%; six studies), a 47% lower risk of cardiovascular disease mortality (HR 0·53 [0·37-0·77]; I²=78·2%; three studies), a non-significant 6% lower risk of cancer incidence (HR 0·94 [0·87-1·01]; I²=73·7%; two studies), a 37% lower risk of cancer mortality (HR 0·63 [0·55-0·72]; I²=64·5%; three studies), a 14% lower risk of type 2 diabetes (HR 0·86 [0·74-0·99]; I²=48·5%; four studies), a 38% lower risk of dementia (HR 0·62 [0·53-0·73]; I²=0%; two studies), a 22% lower risk of depressive symptoms (HR 0·78 [0·73-0·83]; I²=36·2%; three studies), and a 28% lower risk of falls (HR 0·72 [0·65-0·81]; I²=47·5%; four studies). Studies on physical function (not based on meta-analysis) reported similar inverse associations. The evidence certainty was moderate for all outcomes except for cardiovascular disease mortality (low), cancer incidence (low), physical function (low), and falls (very low). Although 10 000 steps per day can still be a viable target for those who are more active, 7000 steps per day is associated with clinically meaningful improvements in health outcomes and might be a more realistic and achievable target for some. The findings of the study should be interpreted in light of limitations, such as the small number of studies available for most outcomes, a lack of age-specific analysis and biases at the individual study level, including residual confounding. National Health and Medical Research Council, New South Wales Health, and Ian Potter Foundation.

Background: The impact of declining physical activity and increased sedentary behaviour in children and adolescents globally prompted the development of national and international physical activity guidelines. This research aims to systematically identify and compare national and international physical activity guidelines for children and adolescents and appraise the quality of the guidelines to promote best practice in guideline development. Methods: This systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) and reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Only national, or international physical activity and/or sedentary behaviour guidelines were included in the review. Included guidelines targeted children and adolescents aged between 5 and 18 years. A grey literature search was undertaken incorporating electronic databases, custom Google search engines, targeted websites and international expert consultation. Guideline quality was assessed using the Appraisal of Guidelines for Research and Evaluation II Instrument (AGREE II). Results: The search resulted in 50 national or international guidelines being identified. Twenty-five countries had a national guideline and there were three international guidelines (European Union, Nordic countries (used by Iceland, Norway and Sweden), World Health Organization (WHO)). Nineteen countries and the European Union adopted the WHO guidelines. Guidelines varied in relation to date of release (2008 to 2019), targeted age group, and guideline wording regarding: type, amount, duration, intensity, frequency and total amount of physical activity. Twenty-two countries included sedentary behaviour within the guidelines and three included sleep. Total scores for all domains of the AGREE II assessment for each guideline indicated considerable variability in guideline quality ranging from 25.8 to 95.3%, with similar variability in the six individual domains. Rigorous guideline development is essential to ensure appropriate guidance for population level initiatives. Conclusions: This review revealed considerable variability between national/international physical activity guideline quality, development and recommendations, highlighting the need for rigorous and transparent guideline development methodologies to ensure appropriate guidance for population-based approaches. Where countries do not have the resources to ensure this level of quality, the adoption or adolopment (framework to review and update guidelines) of the WHO guidelines or guidelines of similar quality is recommended. Trial registration: Review registration: PROSPERO 2017 CRD42017072558.

It remains unclear whether the time-use composition of 24-h movement behaviours (sleep, sedentary time (ST), physical activity (PA)) and recreational screen use are independently associated with psychosocial health. This study examined the cross-sectional and longitudinal associations between 24-h movement behaviour composition, recreational screen use and psychosocial health outcomes in children. Measures completed at baseline (n = 127; 11.7 years) and follow-up (n = 88; 12.8 years) included accelerometer-based 24-h movement behaviours, self-reported recreational screen use and psychosocial health (Strengths and Difficulties Questionnaire, Kessler’s Psychological Distress Scale). Linear mixed models were used to examine the cross-sectional and longitudinal associations between the 24-h movement behaviour composition and recreational screen use levels with psychosocial health outcomes. Overall, the movement behaviour composition (p < 0.05) and recreational screen use levels (p < 0.01) were both cross-sectionally but not longitudinally associated with psychosocial health outcomes. Relative to other behaviours, sleep was negatively associated, while light-intensity PA was positively associated with internalising problems and total difficulties scores. ST was positively associated with internalising problems. High levels of recreational screen use (>2 h/day) were associated with greater externalising problems, total difficulties scores and psychological distress. These findings reinforce the importance of achieving a balance between different types of movement behaviours over a 24-h period for psychosocial health.