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People’s physical activity (PA) throughout an entire day is a key determinant of health. Health is not only influenced by PA of moderate-to-vigorous intensity (MVPA), but also by lighter intensity, as well as daily doses of sitting and standing. Thus, PA (and its absence) in any domain of the day should not be ignored in the investigation and promotion of health. We therefore think it is unfortunate that two complementary research disciplines—public health and occupational health—have essentially been incommunicado divorcees for the past 60 years.
PA research in public and occupational health started united during the 1950s—recall the studies of work-related PA by Morris (London bus drivers)1 and Paffenbarger (San Francisco longshoremen).2 Today, however, the two fields rarely engage in meaningful collaboration. Work-related PA was barely mentioned in the US 2018 Physical Activity Guidelines Advisory Committee Scientific Report,3 as ‘Most of the research findings summarized for this report are based on studies of leisure time PA’.3
In this editorial, we answer the question ‘Where did it all go wrong?’ and recommend ways for ‘remarrying’ the disciplines in order to develop coherent advice for adults from all walks of life.
Where did it all go wrong?
There are three reasons for the diverged directions of public and occupational health. First, the two disciplines operate in silos, and understand and interpret PA differently; this leads to different PA health advice for people in manual jobs (table 1). Silos have a role, but they are not venues for collaboration and cross fertilisation of ideas. Second, public and occupational health research have developed different taxonomies for PA (table 2). Hence, publications in the ‘other’ research discipline are overlooked in literature searches and evidence consolidation. Third, despite common research designs (eg, cohort studies) and methods to measure PA (eg, questionnaires and increasingly device-based measures), fundamental differences in defining PA at leisure and work exist.
We illustrate these two different PA perspectives in figure 1A using the example of a working day of a middle-aged cleaner, who travels to and from work by car, working on her feet for 7.5 hours while doing 20 000 steps at low-intensity PA, then returning home to be sedentary.4 According to recent public health PA guidelines ‘adults should move more and sit less throughout the day, and adults who sit less and do any amount of MVPA will improve health’, so these guidelines would encourage her to replace her sitting during transport and leisure with MVPA (figure 1B). Even though this guideline is primarily aimed at sedentary adults,3 most researchers and practitioners believe that most adults should follow it. However, the occupational health guidelines, which do not offer recommendations for leisure time and treat high levels of PA without sufficient rest (eg, by sitting) as harmful,5 would recommend her to ‘take more sitting breaks at work’ (figure 1C).
Such contradictory advice is a particular problem for millions of workers worldwide whose jobs involve considerable manual labour (such as construction, manufacturing and eldercare) or standing (such as assembly and retail), but are sedentary at leisure.6 For example, 32% of the working population in European Union carry or move heavy loads for at least 25% of their working day,7 and accelerometer studies show that several blue-collar occupations spend 5 working hours or more on their feet per day.6 For health benefits, should such workers follow the public health advice to ‘sit less and do more MVPA’3 or the occupational health advice to ‘reduce PA and rest more’ 5? Do you find this confusing? We are sure policy-makers, stakeholders and people with manual jobs are confused too. Contradictory advice obviously makes it difficult for health messaging to reach manual workers and it may even compromise the longevity and life quality for millions of people in manual jobs.
For example, particularly for workers who are barely permitted to sit at work, the public health recommendation to sit less and do more MVPA can be detrimental and might increase the risk for back pain, vascular and perinatal problems, or even premature mortality.8
What can be done?
We suggest the following practical ways to bring the agenda of the two disciplines together:
Gain support for a common ‘whole of day’ mindset.
Explain to research funders, trade unions, employers’ organisations, insurance companies and pension funds the likely economic, health, and societal benefits of common methods for surveillance and research in leisure and occupational PA.
Develop joint education opportunities for students, practitioners and researchers from both disciplines, where they can meet, interact, share ideas, knowledge and methods, and collaborate.
Prevent confusing advice reaching the public through a suite of common messaging and advocacy standards that researchers from both public and occupational health disciplines will have at their disposal to communicate with the ‘real world’.
Support, encourage and advocate organisations of authority to involve researchers from both disciplines to share expertise and knowledge during guideline-developing efforts.
Conclusion: remarriage here and now
Using the example of the cleaner, in figure 1D, we show what a proposal for a remarriage between the public and occupational health advice could look like. Such a remarriage would strengthen the reach and impact of PA recommendations for all. Moreover, remarriage could be a catalyst for great research and policy endeavours, and eventually a healthier population.
Twitter @profHoltermann, @M_Stamatakis
Contributors AH wrote the first draft of the manuscript. All authors contributed, discussed and accepted the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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