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Introduction: In industrialized societies, physical activity (PA) is decreasing while sedentary behavior (SB) is increasing, leading to health risks. Guidelines based on the relationship between PA/SB and health outcomes are needed to mitigate risks, but current evidence is limited and inconsistent. Advances in measurement tools offer the potential for a more consistent evidence base. This work proposes metrics and assessment methods that can be used to quantify and evaluate work-related PA and SB in the framework of CUELA risk assessment.

Methods: Literature was reviewed for measurement systems and output parameters. Suitable devices and relevant metrics were summarized, and proposals for assessing SB in the workplace were derived for key activity indicators. To check reasonability and consistency, the proposed assessment approaches were applied to measurements of 52 hybrid office workers, who performed their work in the office (O), at home (HO) and on business trips (BT). PA during a typical working week was recorded using a thigh-worn motion sensor (activPAL 4+).

Results: Sensors worn on one thigh have proven to be valid and reliable in distinguishing body positions and locomotion activities, and different PA intensities in long-time measurements. Suggested metrics range from time portions of body positions and activities, changes between behaviors and bout length distributions to indicators of energy expenditure. Regarding risk assessment of sedentary work, a first approach has been proposed based on general recommendations and publicly available sensor-based exposure data.

We analyzed a total of 1,950 hours of working time. The median of SB portions was highest in the HO at 77.1% (O: 74.1%, BT: 50.4%). The max. length of uninterrupted sitting bouts hardly differed between HO and O (median: 59.3 vs. 58.7min). However, continuous sitting ≥30min accounted for a larger portion in the HO (47%) than in the O (40.5%) and during BT (33.2%). Participants were most and longest active on BT with a median portion at 12.5% and a median max. length of 2.8min (O: 5.8%, 2min; HO: 4.4%, 0.9min). This is also reflected in the risk assessment approach, which tends to classify PA behavior on BT rather in the medium-favorable categories and in the O and HO in the medium-unfavorable categories.

Discussion: The proposed assessment was found to be suitable for PA analysis in office workers in different settings. The metrics allow distinguishing between different activity profiles and highlight relevant differences in the distribution of SB and PA. This initial approach focuses on easy-to-use sensor systems and should be extended to more complex multi-sensor systems that offer detailed assessments including body posture analyses. The opposite extreme – stress caused by excessive activity demands or prolonged standing – should also be integrated.

Conclusion: Standardized PA and SB assessments are essential for collecting data across studies and creating a consistent database to derive dose-response relationships between workplace PA and their health effects. This is crucial for the development of risk assessment guidelines.