Accelerometer-Measured Physical Activity at Work and Need for Recovery: A Compositional Analysis of Cross-sectional Data.

Patrick Crowley,Clas-Håkan Nygård,Ole S Mortensen,Charlotte L Rasmussen,David M Hallman,Matthew L Stevens,Andreas Holtermann

doi:10.1093/annweh/wxz095

Abstract

ObjectivesPrevious research has shown strong associations between occupational physical activity (OPA) and need for recovery (NFR). However this research has only utilized self-reported measures of OPA which may be biased. Thus, there is a need for investigating if the previously documented association between self-reported OPA and NFR can be found when using technical measures of OPA. There is also the need to investigate whether older workers are particularly susceptible to increased NFR, since age-related declines in physical capacity mean that it is likely these workers will have a higher NFR for a given physical activity. The aim of this study was to investigate the association between technically measured OPA and NFR, and whether this relationship is modified by age.MethodsThis study utilized data from the Danish Physical Activity Cohort with Objective Measurements cohort—comprising Danish workers (n = 840) from the cleaning, manufacturing, and transportation sectors. OPA was measured by accelerometers attached to the thigh and upper back for at least one work day and classified into four physical behaviour categories (sedentary, standing, light, or moderate/vigorous). NFR was measured using a shortened version of the Danish NFR scale. Analysis was conducted using linear regression and isotemporal substitution analyses for compositional data.ResultsThe overall association between OPA and NFR was statistically significant in the unadjusted model (P < 0.001), but not when adjusted for age, sex, occupation, and shift work (P = 0.166). Isotemporal substitution showed small but significant reductions in NFR when increasing sedentary time relative to other behaviours (adjusted: ΔNFR = −0.010 [−0.019; −0.001]). There were no significant interactions between age and OPA (P = 0.409).ConclusionsThis study found significant associations between OPA and NFR, but the effect sizes were small. Reallocating 30 min to sedentary behaviours from other behaviours was associated with a reduced NFR, but the effect size may not be practically relevant. Moreover, no clear modifying effects of age were identified.

Highlights

The ageing population is a major challenge for modern economies
The overall association between occupational physical activity (OPA) and need for recovery (NFR) was statistically significant in the unadjusted model (P < 0.001), but not when adjusted for age, sex, occupation, and shift work (P = 0.166)
This study found significant associations between OPA and NFR, but the effect sizes were small

Summary

Introduction

The ageing population is a major challenge for modern economies This is mainly because increased age will increase the proportion of the population outside the workforce relative to those being productively employed (OECD, 2006). Increasing the retirement age comes with several challenges, for vulnerable groups (e.g. low skilled, manual workers) (Andersen et al, 2016; Kadefors et al, 2019). This is because increasing the retirement age does not change the capacity of workers to conduct their work (Schofield et al, 2008; Kadefors et al, 2019). To enable these vulnerable groups to remain in the workforce until the elevated retirement age, a thorough understanding of the risk factors for leaving the workforce is required

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