The enthusiasm for standing or treadmill desks took a bit of a hit last month. After reviewing all the current evidence, a group of Cochrane reviewers reported that it’s unclear whether such desks have any positive effect on health — or even if they reduce the amount of time desk-bound workers spend sitting.
The problem, said the reviewers, is that existing studies on the topic are too small or too poorly designed to be conclusive.
This is not an inconsequential issue. Finding ways to reduce the amount of time office workers (and others) spend sitting has become a major focus of preventive health experts. A growing number of studies suggest that prolonged sedentary time puts people at increased risk of disease and premature death — even when they exercise regularly.
And office workers spend about 70 percent of their eight-hour workday sitting.
But don’t give up on your standing desk — yet. For a new randomized controlled trial (one that involved more than 300 office workers) has found that encouraging people to try various strategies to reduce their sitting time — including the use of a standing desk — can result in some potential health-related benefits.
The workers in the study who were urged to spend less time in a chair not only stood more during their work day, they also walked more. And they lost about a half-percentage, on average, of their body fat within three months.
That isn’t a huge amount, but it is “noteworthy in the light of the increasing prevalence of excess weight and obesity and the high proportion of people with sedentary work,” say the authors of the study.
For the study, which was published Wednesday in the International Journal of Epidemiology, Danish and Australian researchers recruited 317 workers at 19 offices in Denmark and Greenland.
All the workers already had adjustable sit-stand desks, but most of them were not using the “stand” feature. (In Denmark, employers are required to offer their employees such desks. The desks are assigned primarily for ergonomic reasons, however, rather than to help people be less sedentary.)
The researchers randomly assigned some of the offices (equivalent to about half of the participating workers) to an “intervention” program called “Take a Stand!” It had many components, including an educational workshop that presented information on the importance of breaking up prolonged periods of sitting. The workers also received e-mails and text messages with reminders about getting up and moving around. Their managers also encouraged them to take breaks from sitting during the workday.
The rest of the offices — the “control” group — received no such information or encouragement, and continued working as they had in the past.
All the study’s participants wore an accelerometer, a device that tracks movement, both at home and in the workplace.
The information and behavioral nudging seem to have worked. After one month, the employees in the intervention group were sitting for 71 minutes less per workday than those in the control group. After three months, this difference was smaller, but still significant: 48 minutes.
Most of the reduction in sitting was replaced by standing, presumably because people were opting to use their desk’s stand function more often, say the researchers.
The workers in the intervention group also walked more while at their jobs. At one month, the intervention group was taking 7 percent more steps per workday than those in the control group. That difference increased to 8 percent at three months.
Few workers in the intervention group (less than 6 percent) reported back or leg pain, lower personal productivity or any other negative consequences from standing more and sitting less.
Perhaps most encouraging was the finding that the workers in the intervention group got slightly leaner. After three months, their body fat fell 0.61 percentage points compared with that of the control group.
The drop in body fat appears to be the result only of the sitting-standing-walking changes adopted at the workplace. Data from the accelerators revealed no differences between the intervention and control groups in their leisure-time sitting, walking or other physical activities.
Caveats and corporate responsibility
The study has several limitations, including one brought up by the Cochrane reviewers in their criticism of earlier studies on this topic: It ran for only three months. It’s not clear if the results would be sustainable for a longer stretch of time, and the fact that the workers in the study were on their feet less at three months than at one month is not encouraging.
And, of course, the overall changes were relatively modest.
Still, the results are interesting, particularly given that most office workers in the U.S. sit an average 11 hours a day, primarily at work.
“A reduction in sitting time by 71 [minutes] per day and increase in interruptions could have positive effects and, in the long run, could be associated with reduced risk of heart disease, diabetes and all-cause mortality, especially among those who are inactive in their leisure time,” say the study’s authors.
Employers should take note, they add.
“In modern society, a number of professions entail sitting for long hours each day,” the researchers write. “Thus, as health risks associated with being sedentary emerge, it become relevant to view prolonged sitting like any other factor that is associated with safety at work and a corporate responsibility.”
FMI: The study is behind a paywall, but you’ll find an abstract at the International Journal of Epidemiology’s website.