Background: Prolonged sitting time is detrimental for health. Individuals with desk-based occupations tend to sit a great deal and sit-stand workstations have been identified as a potential strategy to reduce sitting time. Hence, the objective of the current study was to examine the effects of using sit-stand workstations on office workers’ sitting time at work and over the whole day.
Methods: We conducted a randomized controlled trial pilot with crossover design and waiting list control in Sydney, Australia from September 2011 to July 2012 (n = 42; 86% female; mean age 38 ± 11 years). Participants used a sit-stand workstation for four weeks in the intervention condition. In the time-matched control condition, participants received nothing and crossed over to the intervention condition after four weeks. The primary outcomes, sitting, standing and walking time at work, were assessed before and after using the workstations with ActivPALs and self-report questionnaires. Secondary outcomes, domain-specific sitting over the whole day, were assessed by self-report. Linear mixed models estimated changes in outcomes adjusting for measurement time, study grouping and covariates.
Results: Intervention participants significantly reduced objectively assessed time spent sitting at work by 73 min/workday (95% CI: −106,-39) and increased standing time at work by 65 min/workday (95% CI: 47, 83); these changes were significant relative to controls (p = 0.004 and p < 0.001, respectively). Total sitting time significantly declined in intervention participants (−80 min/workday; 95% CI: −155, −4).
Conclusions: This study shows that introducing sit-stand workstations in the office can reduce desk-based workers’ sitting time at work in the short term. Larger scale studies on more representative samples are needed to determine the public health impact of sit-stand workstations.
Alex’s Notes: Incredibly, working adults spend one-third to three-quarters of their time sitting. But why do they sit so much? The answer is rather simple; they sit because that is how the work environment operates. If you change the environment, you change the worker. Sit-stand workstations allow for easy alternation between sitting and standing at one’s desk, and the current study aims to examine the effect of using a sit-stand workstation on worker sitting time both within the office and during the remainder of the day. It was aptly names the [email protected] study.
Forty-two non-governmental health agency employees were recruited from New South Wales, Australia to participate in the study. In addition to the majority (82%) being female, 81% worked full-time, 79% had a University degree, 25% were overweight, 13% were obese, and the average age was 38-years. The study design was interesting, and at the risk of confusing you, I will do my best to explain it. Each participant drew a slip of paper randomly out of a ballot that was labelled with a number 1-9. There were 4-5 ballots each that had the same number on them, so that the end result was nine groups of four to five participants. Group #1 was the first intervention group, while group #2 served as the control, and the other groups were put on a waitlist. After a 4-week intervention, group #2 became the intervention group, while group #3 served as a control, and the other groups including #1 were put on a waitlist. This pattern continued until all groups experienced the intervention, which was simply providing the workers with a sit-stand station and instructions on how to use it.
Assessments, consisting of objective monitoring via an ActivPAL activity monitor and self-report questionnaires, took place at three time points scheduled four weeks apart. Assessment 1 was six weeks pre-intervention, assessment 2 at two weeks pre-intervention, and assessment 3 in the third week of the intervention. Changes between assessments 1 and 2 were treated as the control condition, changes between assessments 2 and 3 as the intervention condition.
Sitting at work
Not surprisingly, both objective and subjective time spent sitting at work was significantly reduced during the intervention by 73 and 91 minutes, respectively, and time spent standing was significantly increased by 65 and 99 minutes, respectively. I can’t help but laugh at the differences between the objective and subjective measurements. With differences of 25-50% is it any wonder that questionnaires can be grossly inaccurate? Objectively measured time spent stepping also tended to increase in the intervention group by 11 minutes (p=0.081).
Sitting at home
Unfortunately, all measurements regarding activity outside of the office were self-reported, and as we could clearly see above, may not be entirely accurate. That said, there was a significant reduction in total daily sitting time in the intervention group by 80 minutes over the course of the workday, of which 74 were from work itself. There was also a significant 26 minute reduction in time spent watching TV, but with no other significant changes in transportation, using a computer, or other leisure activities, the only explanation could be that most of this TV-viewing time was spent at work. That or the time was just eliminated from existence… or more likely it is a reporting error inherent to subjective assessments. Interestingly, the control groups also significantly reduced TV time by 30 minutes.
Over the course of a non-workday, there was again a significant 46 minute reduction in TV viewing time in the intervention group (but not the control group), and no concomitant changes in time spent doing other things. Nonetheless, the reduction of TV viewing time would be a welcomed side-effect of the intervention.
When provided the opportunity to stand, workers will, as demonstrated by the reductions in workday sitting time. While the exact amount of sitting and/or standing to have a significant impact on health remains to be determined, encouraging persons to sit less and possibly move more is always something to strive for. The short-term follow-up of the study was unfortunate, and we must also remember that the subjects were college-graduate females of mainly normal BMI working in a health-related field. Thus, future work should examine the feasibility of sit-stand stations on more “at-risk” populations in other desk-based occupations.