Prolonged sedentary behaviour (SB) is an independent risk factor for adverse health outcomes, with current WHO guidelines emphasising both increased physical activity (PA) and reduced sitting time. While electronic health (eHealth) interventions offer scalable solutions, the comparative effectiveness of two dominant strategies: sedentary break interventions (frequent interruptions of sitting) versus PA promotion (structured activity sessions) remains unclear. This systematic review and meta-analysis protocol aims to compare the effectiveness of interventions targeting breaks in SB versus increased PA in reducing sedentary time through meta-analysis of randomised controlled trials (RCTs) comparing either intervention to a control condition, while exploring key moderating factors including participant characteristics, intervention type, duration, eHealth delivery mode, theoretical basis, use of behaviour change techniques (BCTs), PA intensity and SB frequency.

This protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines. A comprehensive search will be conducted in PubMed, Embase, Web of Science and the Cochrane Library from inception to 31 July 2025, with language restrictions limited to English and Chinese publications. RCTs comparing eHealth-delivered interventions promoting sedentary breaks with those increasing PA in adults will be included. The primary outcome is sedentary time (objectively measured or self-reported), and secondary outcomes include health outcomes such as cardiometabolic markers, fatigue and well-being. Two reviewers (SC and XN) will independently screen studies, extract data and assess risk of bias using validated tools. Meta-analyses will be performed if sufficient homogeneous data are available, comparing changes in sedentary time. Subgroup analyses will explore effects by participant characteristics including gender (male vs female), age groups (3 to

Ethical approval is not required as this study involves secondary analysis of published data. Findings will be disseminated through peer-reviewed publication and conference presentations.

CRD420251042994.

To address the growing prevalence of sedentary behaviours among older adults and their associated adverse health outcomes, there is an urgent need to prioritise effective and accessible interventions. Mobile health (mHealth) delivers healthcare services and health-related information through portable electronic devices, enabling interventions to be administered directly in home settings. However, the evidence on the effectiveness of mHealth interventions in reducing sitting time among older adults remains inconsistent. To derive literature-based estimates of the effectiveness of mHealth interventions, we will systematically review and meta-analyse the impact of these interventions on sitting time in adults aged 55 years and older.

An electronic search of PubMed, Embase, Web of Science and Cochrane will be conducted from database inception to March 2025 to identify randomised controlled trials evaluating the effects of mHealth interventions on sitting time during waking hours, excluding sleep duration. Subgroup analyses will explore potential moderators (eg, participant characteristics, intervention specifics). Studies from all settings (eg, community, long-term care facilities, etc) will be considered. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines will be explicitly applied for structuring this report. Methodological quality will be assessed using the Cochrane Handbook tool. Two independent reviewers will screen the studies and extracted data, with methodological quality to be assessed using established criteria. Meta-analyses will be performed using Review Manager v.5.4 software.

This study uses secondary data and, therefore, does not require ethics approval. The findings will be communicated through presentations at international conferences and published in peer-reviewed journals. The results will inform the development of future mHealth interventions aimed at reducing sedentary behaviour in older adults and provide benchmarks for the effectiveness of technology-driven public health strategies. This protocol adheres to the PRISMA guidelines and follows the Cochrane Handbook for Systematic Reviews of Interventions for methodological rigour.

CRD42023443926.