Adjustable desks could improve work performance by reducing sitting time

"Scrapping traditional desks could improve workers' performance and health," reports the Mail Online.

The amount of time people spend sitting down has been linked to poor health and long-term medical conditions. Many office workers spend much of their day seated, which could have a harmful effect on their health.

A study of 146 NHS office workers found that providing adjustable desks that allowed them to sit or stand led to a reduction in daily sitting time of more than an hour, after 12 months of use. The desks were provided as part of a wider programme that included goal setting and coaching to encourage people to sit less at work, especially for long uninterrupted periods.

The study also found that workers provided with adjustable desks reported better job performance, reduced sickness at work, less anxiety and improved quality of life. However, the size of the study means we can't be sure of the accuracy of these secondary outcomes.

Find out more about the benefits of physical activity.

Where did the story come from?

The study was carried out by researchers from Leicester General Hospital and Loughborough University in the UK and the University of Southern Queensland and Baker Heart and Diabetes Institute in Australia. It was funded by Loughborough University, the Department of Health and the National Institute of Health Research. It was published in the British Medical Journal on an open-access basis so it is free to read online.

Most of the UK media reports focused on the improved work performance reported by people with adjustable desks. However, this finding relied on people's responses to one question in the group of tests and outcomes measured in the study, and represents a relatively small change (0.5 on a scale of 1 to 7), the significance of which is unclear.

What kind of research was this?

This was a cluster randomised controlled trial. The workers were in small offices within a large organisation, and randomly assigned at office level. Researchers wanted to find out if a programme including adjustable desks could reduce time spent sitting during the working day, as well as during the full day (ie outside of work).

What did the research involve?

Researchers recruited office-based workers at University Hospitals of Leicester NHS Trust, who were sitting and working more than half the time.

They randomised the workers in office-based clusters to continue as usual (control group) or take part in a programme designed to reduce sitting (Stand More AT Work or SMArT programme), where adjustable desks were provided.

Participants wore monitoring devices on their thighs for 7 consecutive days at the start of the study. They wore them again for the same time period after 3 months, 6 months and 12 months. The devices collected information about whether a person was standing, sitting or walking. At the same time, they wore accelerometers to measure their physical activity levels.

Participants also filled in questionnaires and carried out tests designed to look at work-related health and performance, musculoskeletal problems and mental health.

The SMArT programme included:

  • support and messages from the chief executive of the trust so everyone knew it was backed by senior management
  • group training in the health benefits of reducing sitting
  • provision of adjustable desks and training in how to use them
  • feedback on how much people sat at the start of the study, with encouragement to set goals to reduce sitting
  • coaching sessions at 3 months, 6 months and 12 months

What were the basic results?

The results showed that people in the SMArT group reduced the amount of time they spent sitting down at work, and sitting down overall, when measured at 3, 6 and 12 months.

After a year:

  • people in the SMArT group sat for 82 minutes less per day at work than those in the control group (adjusted mean difference -81.64, 95% confidence interval (CI) -112.27 to -51.01)
  • people in the SMArT group sat for 82 minutes less per day overall, suggesting that the reduction in overall sitting time was down to sitting at work, not during the rest of the day (adjusted mean difference -82.39, 95% CI -114.54 to -50.26)

The reduction in sitting time was mirrored by an increase in standing time. People in the SMArT group did not increase their physical activity levels over the course of the study, or their time spent walking.

Looking at the work-related measures, researchers found after 12 months:

  • an increase in engagement at work for the SMArT group (0.44 adjusted difference on a scale of 0 to 6, 95% CI 0.28 to 0.61)
  • an increase in self-reported job performance for the SMArT group (0.53 adjusted difference on a scale of 1 to 7, 95% CI 0.20 to 0.86)
  • a reduction in "presenteeism" (working while performance is impaired by health problems) for the SMArT group (0.25 adjusted difference on a scale of 1 to 5, 95% CI -0.08 to 0.58)

There was no difference in job satisfaction or sickness absence from work.

Researchers also found a small reduction in some types of musculoskeletal problems among the SMArT group.

How did the researchers interpret the results?

The researchers said their results showed the SMArT programme "was able to reduce occupational and daily sitting time in the short, medium and longer term in office workers within the University Hospitals of Leicester NHS Trust." They added that it "appeared to have a positive impact on musculoskeletal conditions and many work-related outcomes".

Conclusion

It's difficult to follow advice to sit down less and be more active when you work in a traditional office environment, where you are expected to work on a computer, sitting at a desk for most of the day. So the introduction of adjustable desks, which allow people to work standing up as well as sitting down, could make a big difference to a lot of people.

The study shows that it is possible to reduce the amount of time people spend sitting by an hour or more a day. However, this was as part of a big organisation-wide study, involving coaching, goal-setting and monitoring, as well as provision of equipment. We don't know if people would have reduced their sitting time as much if they had been provided with adjustable desks and simply left to get on with it.

Another question is how much of a health impact the intervention actually had. While reduced sitting time is likely to be an improvement, the programme didn't increase the time people spent being physically active. Swapping sitting for standing may not have an enormous health impact, compared to introducing more activity into the day.

There are a few limitations to the study to be aware of:

  • People tend to change their behaviour when they know they are being monitored. It's possible the SMArT group spent more time standing during the days they were wearing the monitor, than when they were not monitored.
  • Quite a lot of people dropped out of the study (27%), mainly in the control group.
  • The researchers measured many different outcomes, but the recruited sample was only large enough to detect differences in the main outcome of time spent sitting.
  • Other secondary outcomes, such as physical activity, work performance or musculoskeletal problems, are less likely to be reliable and some results may be positive by chance.

Nevertheless, this is an interesting study and the results show it is possible to make a fairly big difference in the time spent sitting down with the use of adjustable desks. The question now is whether this could be repeated in other workplaces, and whether other programmes might encourage people to be more active, rather than just to swap sitting for standing.