Reducing sedentary behaviour (SB) in older adults is a promising strategy to promote healthy ageing. However, to develop more effective interventions, more in-depth information is needed on how existing interventions work. The present realist review aims to identify the working mechanisms and contextual preconditions to guide the development of future interventions.

A realist review was conducted following the iterative process of Pawson and Tilley and reported following the RAMESES publication standards.

Evidence was searched in four databases: EMBASE, PubMed, Web of Science and Scopus, and in the grey literature.

All study types and designs were included. Studies conducted in older adults with a mean age of 60 years or older, providing information on the context, mechanisms and/or outcomes of interventions aimed at the reduction of SB were eligible for inclusion and appraised for relevance and rigour.

All data were coded by two independent reviewers. Sections that contained relevant information to refine, refute or confirm the initial programme theory were given a code. Based on these codes, context-mechanism-outcome configurations were made, and a final programme theory was developed.

In total, 58 studies, from 61 articles, were eligible. The review revealed three important contexts for changes in SB: the (1) motivation, (2) opportunities and (3) capabilities of older adults. Depending on the context, other behaviour change techniques should be used to trigger specific mechanisms and, in turn, reduce SB. Especially, the impact of the underlying automatic processes of SB on the effectiveness of SB interventions became clear. Existing interventions primarily focus on the reflective processes guiding SB, without taking into account that SB is often an automatic response that occurs unconsciously, with little reasoning.

The effectiveness of SB interventions in older adults highly depends on the context in which the interventions occur. In particular, the context of automatic motivation should receive more attention to break the ingrained habit of SB in older adults.

Regular physical activity (PA) and reduced sedentary behaviour (SB) have been associated with positive health outcomes, but many older adults do not comply with the current recommendations. Sensor-triggered ecological momentary assessment (EMA) studies allow capturing real-time data during or immediately after PA or SB, which can yield important insights into these behaviours. Despite the promising potential of sensor-triggered EMA, this methodology is still in its infancy. Addressing methodological challenges in sensor-triggered EMA studies is essential for improving protocol adherence and enhancing validity. Therefore, this study aimed to examine (1) the patterns in sensor-triggered EMA protocol adherence (eg, compliance rates), (2) the impact of specific settings (eg, event duration) on the number of prompted surveys, and (3) participants’ experiences with engaging in a sensor-triggered EMA study.

Two longitudinal, sensor-triggered EMA studies—one focused on PA and the other on SB—were conducted using similar methodologies from February to October 2022. Participants’ steps were monitored for seven days using a Fitbit activity tracker, which automatically prompted an EMA survey through the HealthReact smartphone application when specified (in)activity thresholds were reached. After the monitoring period, qualitative interviews were conducted. Data from both studies were merged.

The studies were conducted among community-dwelling Belgian older adults.

The participants had a median age of 72 years, with 54.17% being females. The PA study included 88 participants (four dropped out), while the SB study included 76 participants (seven dropped out).

Descriptive methods and generalised logistic mixed models were employed to analyse EMA adherence patterns. Simulations were conducted to assess the impact of particular settings on the number of prompted EMA surveys. Additionally, qualitative interview data were transcribed verbatim and thematically analysed using NVivo.

Participants responded to 81.22% and 79.10% of the EMA surveys in the PA and SB study, respectively. The confirmation rate, defined as the percentage of EMA surveys in which participants confirmed the detected behaviour, was 94.16% for PA and 72.40% for SB. Logistic mixed models revealed that with each additional day in the study, the odds of responding to the EMA survey increased significantly by 1.59 times (OR=1.59, 95% CI: 1.36 to 1.86, p

This study demonstrates the potential of sensor-triggered EMA to capture real-time data on PA and SB among older adults, showing strong adherence potential with compliance rates of approximately 80%. The SB study had lower confirmation rates than the PA study, due to technical issues and discrepancies between self-perception and device-based measurements. Practical recommendations were provided for future studies, including improvements in survey timing, technical reliability and strategies to reduce latency.