Standing desks alongside other measures cut office workers' sitting time by an hour a day

Using a standing desk alongside a package of other measures to encourage office workers to sit less and move more, reduced sitting time by about an hour a day over one year, finds a trial published in The BMJ today.

These measures were also linked to small improvements in stress, wellbeing, and energy levels at work, although the researchers stress that these improvements were not clinically meaningful. 

A growing body of evidence indicates that sedentary lifestyles are associated with higher levels of chronic disease, including heart diseases, type 2 diabetes, and some cancers, and higher rates of depression and anxiety. 

Office-based workers are one of the most sedentary populations, spending 73% of their workday and 66% of their waking day sitting, but studies looking at ways to reduce sitting in the workplace have been deemed low quality. 

To address these research gaps, a team of researchers based in the UK, with collaborators in Australia set out to evaluate the impact of SMART Work & Life (SWAL), an intervention designed to reduce sitting time and increase moving time at work, with and without a standing desk, delivered by workplace champions.

The trial involved 756 office workers from two councils in Leicester, three in Greater Manchester, and one in Liverpool. Participants were randomly assigned to the SWAL intervention, the SWAL intervention with a standing desk, or a control group (working as usual) over a 12 month period.

The average age of participants was 45, of which 72% were women, 75% were white British, and 85% worked full time. Average body mass index (BMI) at the start of the study was 26.5. 

The SWAL intervention group were given a range of resources to help them reduce their sitting time, and highlight the health risks of too much sitting.

Workplaces were also encouraged to make small changes around the office to enable more movement, such as relocating printers and waste paper bins and creating standing areas for meetings.

The SWAL plus desk group also received a height adjustable desk to encourage less sitting time. The control group carried on working as usual.

Workers’ sitting time was measured using a device (accelerometer) worn on the thigh at the start of the study and again at 12 months.

Daily physical activity levels, and self-reported feedback about work, physical and mental health were also recorded.

The SWAL intervention plus standing desk was three times more effective at reducing sitting time than the SWAL intervention alone.

For example, at 12 months, daily sitting time for the SWAL group, and the SWAL plus standing desk were, respectively, 22 minutes and 64 per day minutes lower on average than the control group.  

Small, but non-clinically meaningful improvements in stress, wellbeing, and a sense of work-related vigour were found for both intervention groups compared with the control group at three and 12 months, as well as lower limb pain (hips, knees and ankles) in the SWAL plus desk group.

Although time spent sitting was lower in both intervention groups compared with the control group, the researchers note that most participants simply replaced sitting with standing, and they say further work is needed to encourage more physical activity, particularly outside of working hours.

A randomised controlled trial is considered the most reliable way to determine whether an intervention actually has the desired effect, but the researchers do point to some limitations.

For example, participants were aware of the purpose of the device measuring their movement, which could have impacted their behaviour. And participants may have been selective in their responses to questionnaires - a phenomenon known as ‘reporting bias.’

However  this was a large, well-designed trial that mimicked a real world intervention, and results were similar after further sensitivity analyses, suggesting that they are robust.

They also point out that participants were selected from three different areas in England, which bolsters the case for wider roll-out of the findings. 

As such, the researchers say both SWAL and SWAL plus desk were associated with a reduction in sitting time, although the addition of a height adjustable desk was found to be threefold more effective.

And they point to areas for future research, such as exploring how people can best be supported to make changes outside of work and increase time spent moving, across different employment sectors and for a longer time period. 

In a linked editorial, Professor Cindy Gray from the University of Glasgow says: “The findings are noteworthy because they come from a fully powered cluster randomised trial with objective measurement of sedentary behaviour at three and 12 months.”

However, she points out that the move to more home based and blended patterns of working after the covid-19 pandemic is likely to increase workforce sedentariness. Therefore, she says “understanding how to optimise occupational interventions to support people to sit less and move more around their home during both work and non-working hours is essential.”

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