Stress is nearly ubiquitous in everyday life; however, it imposes a tremendous burden worldwide by acting as a risk factor for most physical and mental diseases. The effects of geographic environments on stress are supported by multiple theories acknowledging that natural environments act as a stress buffer and provide deeper and quicker restorative effects than most urban settings. However, little is known about how the temporalities of exposure to complex urban environments (duration, frequency and sequences of exposures) experienced in various locations – as shaped by people’s daily activities – affect daily and chronic stress levels. The potential modifying effect of activity patterns (ie, time, place, activity type and social company) on the environment–stress relationship also remains poorly understood. Moreover, most observational studies relied quasi-exclusively on self-reported stress measurements, which may not accurately reflect the individual physiological embodiment of stress. The FragMent study aims to assess the extent to which the spatial and temporal characteristics of exposures to environments in daily life, along with individuals’ activity patterns, influence physiological and psychological stress.

A sample of 2000 adults aged 18–65 and residing in the country of Luxembourg completed a traditional and a map-based questionnaire to collect data on their perceived built, natural and social environments, regular mobility, activity patterns and chronic stress at baseline. A subsample of 200 participants engaged in a 15-day geographically explicit ecological momentary assessment (GEMA) survey, combining a smartphone-enabled global positioning system (GPS) tracking and the repeated daily assessment of the participants’ momentary stress, activities and environmental perceptions. Participants further complete multiple daily vocal tasks to collect data on vocal biomarkers of stress. Analytical methods will include machine learning models for stress prediction from vocal features, the use of geographic information systems (GIS) to quantify dynamic environmental exposures in space and time, and statistical models to disentangle the environment–stress relationships.

Ethical approval (LISER REC/2021/024.FRAGMENT/4-5-9-10) was granted by the Research Ethics Committee of the Luxembourg Institute of Socio-Economic Research (LISER), Luxembourg. Results will be disseminated via conferences, peer-review journal papers and comic strips. All project outcomes will be made available at https://www.fragmentproject.eu/.

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.