Impact of sit-stand desks at work on energy expenditure and sedentary time: protocol for a feasibility study

Natural Patterns of Sitting, Standing and Stepping During and Outside Work-Differences between Habitual Users and Non-Users of Sit-Stand Workstations

Sit-stand workstations have shown to reduce sitting time in office workers on a group level. However, movement behaviour patterns might differ between subgroups of workers. Therefore, the objective of this study was to examine sitting, standing and stepping outcomes between habitual users and non-users of sit-stand workstations. From an international office population based in the Netherlands, 24 users and 25 non-users of sit-stand workstations were included (all had long-term access to these workstations). Using the ActivPAL, sitting, standing and stepping were objectively measured during and outside working hours. Differences in outcomes between users and non-users were analysed using linear regression. During working hours, users sat less (-1.64; 95% IC= -2.27--1.01 hour/8 hour workday) and stood more (1.51; 95% IC= 0.92-2.10 hour/8 hour workday) than non-users. Attenuated but similar differences were also found for total sitting time over the whole week. Furthermore, time in static standing bouts was relatively high for users during working hours (median= 0.56; IQR = 0.19-1.08 hour/8 hour workday). During non-working hours on workdays and during non-working days, no differences were found between users and non-users. During working hours, habitual users of their sit-stand workstation sat substantially less and stood proportionally more than non-users. No differences were observed outside working hours, leading to attenuated but similar differences in total sitting and standing time between users and non-users for total days. This indicated that the users of sit-stand workstations reduced their sitting time at work, but this seemed not to be accompanied by major carry-over or compensatory effects outside working hours.

Impact of sit-stand desks at work on energy expenditure, sitting time and cardio-metabolic risk factors: Multiphase feasibility study with randomised controlled component

Uncertainties remain about the overall effect of sit-stand desks for reducing prolonged sitting among office-based workers. This study assessed the feasibility of a randomised controlled trial of the impact of workplace sit-stand desks on overall energy expenditure, sitting time and cardio-metabolic outcomes. It involved four phases: Phase I: online survey; Phase II: workspace auditing; Phase III: randomised intervention (provision of sit-stand desks at work for 3 months); Phase IV: qualitative component. Participants were offıce-based employees of two companies in Cambridge, England. Among Phase I participants interested in the trial, 100 were randomised to Phase II. Of those with workspaces suitable for sit-stand desks, 20 were randomised to Phase III. Those allocated to the intervention completed Phase IV. Outcomes included: trial participation interest, desk-type (full desks/desk mounts) and assessment location (work/laboratory/home) preferences (Phase I); proportion of workspaces permitting sit-stand desk installation (Phase II); energy expenditure, sitting time and cardio-metabolic outcomes (Phase III); study participation experiences (Phase IV). Data were collected between May 2015 and December 2016. Recruitment and trial implementation were feasible: 92% of survey respondents expressed participation interest; 80% of workspaces could accommodate sit-stand desks; assessments were done in workplaces, preferred by 71%. Sit-stand desk provision reduced workplace sitting time by 94 min/day (95% CI 17.7-170.7). Their impact on energy expenditure and cardio-metabolic outcomes is unclear. The results confirm the feasibility of a trial assessing sit-stand desks' impact on energy expenditure, sitting time and cardio-metabolic outcomes, which should reduce uncertainty concerning the intervention's potential to reduce the health risks of prolonged sitting. Trial registration ISRCTN44827407.

Workplace interventions for reducing sitting at work

BACKGROUND

A large number of people are employed in sedentary occupations. Physical inactivity and excessive sitting at workplaces have been linked to increased risk of cardiovascular disease, obesity, and all-cause mortality.

OBJECTIVES

To evaluate the effectiveness of workplace interventions to reduce sitting at work compared to no intervention or alternative interventions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, OSH UPDATE, PsycINFO, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) search portal up to 9 August 2017. We also screened reference lists of articles and contacted authors to find more studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cross-over RCTs, cluster-randomised controlled trials (cluster-RCTs), and quasi-RCTs of interventions to reduce sitting at work. For changes of workplace arrangements, we also included controlled before-and-after studies. The primary outcome was time spent sitting at work per day, either self-reported or measured using devices such as an accelerometer-inclinometer and duration and number of sitting bouts lasting 30 minutes or more. We considered energy expenditure, total time spent sitting (including sitting at and outside work), time spent standing at work, work productivity and adverse events as secondary outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts and full-text articles for study eligibility. Two review authors independently extracted data and assessed risk of bias. We contacted authors for additional data where required.

MAIN RESULTS

We found 34 studies - including two cross-over RCTs, 17 RCTs, seven cluster-RCTs, and eight controlled before-and-after studies - with a total of 3,397 participants, all from high-income countries. The studies evaluated physical workplace changes (16 studies), workplace policy changes (four studies), information and counselling (11 studies), and multi-component interventions (four studies). One study included both physical workplace changes and information and counselling components. We did not find any studies that specifically investigated the effects of standing meetings or walking meetings on sitting time.Physical workplace changesInterventions using sit-stand desks, either alone or in combination with information and counselling, reduced sitting time at work on average by 100 minutes per workday at short-term follow-up (up to three months) compared to sit-desks (95% confidence interval (CI) -116 to -84, 10 studies, low-quality evidence). The pooled effect of two studies showed sit-stand desks reduced sitting time at medium-term follow-up (3 to 12 months) by an average of 57 minutes per day (95% CI -99 to -15) compared to sit-desks. Total sitting time (including sitting at and outside work) also decreased with sit-stand desks compared to sit-desks (mean difference (MD) -82 minutes/day, 95% CI -124 to -39, two studies) as did the duration of sitting bouts lasting 30 minutes or more (MD -53 minutes/day, 95% CI -79 to -26, two studies, very low-quality evidence).We found no significant difference between the effects of standing desks and sit-stand desks on reducing sitting at work. Active workstations, such as treadmill desks or cycling desks, had unclear or inconsistent effects on sitting time.Workplace policy changesWe found no significant effects for implementing walking strategies on workplace sitting time at short-term (MD -15 minutes per day, 95% CI -50 to 19, low-quality evidence, one study) and medium-term (MD -17 minutes/day, 95% CI -61 to 28, one study) follow-up. Short breaks (one to two minutes every half hour) reduced time spent sitting at work on average by 40 minutes per day (95% CI -66 to -15, one study, low-quality evidence) compared to long breaks (two 15-minute breaks per workday) at short-term follow-up.Information and counsellingProviding information, feedback, counselling, or all of these resulted in no significant change in time spent sitting at work at short-term follow-up (MD -19 minutes per day, 95% CI -57 to 19, two studies, low-quality evidence). However, the reduction was significant at medium-term follow-up (MD -28 minutes per day, 95% CI -51 to -5, two studies, low-quality evidence).Computer prompts combined with information resulted in no significant change in sitting time at work at short-term follow-up (MD -14 minutes per day, 95% CI -39 to 10, three studies, low-quality evidence), but at medium-term follow-up they produced a significant reduction (MD -55 minutes per day, 95% CI -96 to -14, one study). Furthermore, computer prompting resulted in a significant decrease in the average number (MD -1.1, 95% CI -1.9 to -0.3, one study) and duration (MD -74 minutes per day, 95% CI -124 to -24, one study) of sitting bouts lasting 30 minutes or more.Computer prompts with instruction to stand reduced sitting at work on average by 14 minutes per day (95% CI 10 to 19, one study) more than computer prompts with instruction to walk at least 100 steps at short-term follow-up.We found no significant reduction in workplace sitting time at medium-term follow-up following mindfulness training (MD -23 minutes per day, 95% CI -63 to 17, one study, low-quality evidence). Similarly a single study reported no change in sitting time at work following provision of highly personalised or contextualised information and less personalised or contextualised information. One study found no significant effects of activity trackers on sitting time at work.Multi-component interventions Combining multiple interventions had significant but heterogeneous effects on sitting time at work (573 participants, three studies, very low-quality evidence) and on time spent in prolonged sitting bouts (two studies, very low-quality evidence) at short-term follow-up.

AUTHORS' CONCLUSIONS

At present there is low-quality evidence that the use of sit-stand desks reduce workplace sitting at short-term and medium-term follow-ups. However, there is no evidence on their effects on sitting over longer follow-up periods. Effects of other types of interventions, including workplace policy changes, provision of information and counselling, and multi-component interventions, are mostly inconsistent. The quality of evidence is low to very low for most interventions, mainly because of limitations in study protocols and small sample sizes. There is a need for larger cluster-RCTs with longer-term follow-ups to determine the effectiveness of different types of interventions to reduce sitting time at work.

Workplace interventions for reducing sitting at work

BACKGROUND

A large number of people are employed in sedentary occupations. Physical inactivity and excessive sitting at workplaces have been linked to increased risk of cardiovascular disease, obesity, and all-cause mortality.

OBJECTIVES

To evaluate the effectiveness of workplace interventions to reduce sitting at work compared to no intervention or alternative interventions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, OSH UPDATE, PsycINFO, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) search portal up to 9 August 2017. We also screened reference lists of articles and contacted authors to find more studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cross-over RCTs, cluster-randomised controlled trials (cluster-RCTs), and quasi-RCTs of interventions to reduce sitting at work. For changes of workplace arrangements, we also included controlled before-and-after studies. The primary outcome was time spent sitting at work per day, either self-reported or measured using devices such as an accelerometer-inclinometer and duration and number of sitting bouts lasting 30 minutes or more. We considered energy expenditure, total time spent sitting (including sitting at and outside work), time spent standing at work, work productivity and adverse events as secondary outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts and full-text articles for study eligibility. Two review authors independently extracted data and assessed risk of bias. We contacted authors for additional data where required.

MAIN RESULTS

We found 34 studies - including two cross-over RCTs, 17 RCTs, seven cluster-RCTs, and eight controlled before-and-after studies - with a total of 3,397 participants, all from high-income countries. The studies evaluated physical workplace changes (16 studies), workplace policy changes (four studies), information and counselling (11 studies), and multi-component interventions (four studies). One study included both physical workplace changes and information and counselling components. We did not find any studies that specifically investigated the effects of standing meetings or walking meetings on sitting time.Physical workplace changesInterventions using sit-stand desks, either alone or in combination with information and counselling, reduced sitting time at work on average by 100 minutes per workday at short-term follow-up (up to three months) compared to sit-desks (95% confidence interval (CI) -116 to -84, 10 studies, low-quality evidence). The pooled effect of two studies showed sit-stand desks reduced sitting time at medium-term follow-up (3 to 12 months) by an average of 57 minutes per day (95% CI -99 to -15) compared to sit-desks. Total sitting time (including sitting at and outside work) also decreased with sit-stand desks compared to sit-desks (mean difference (MD) -82 minutes/day, 95% CI -124 to -39, two studies) as did the duration of sitting bouts lasting 30 minutes or more (MD -53 minutes/day, 95% CI -79 to -26, two studies, very low-quality evidence).We found no significant difference between the effects of standing desks and sit-stand desks on reducing sitting at work. Active workstations, such as treadmill desks or cycling desks, had unclear or inconsistent effects on sitting time.Workplace policy changesWe found no significant effects for implementing walking strategies on workplace sitting time at short-term (MD -15 minutes per day, 95% CI -50 to 19, low-quality evidence, one study) and medium-term (MD -17 minutes/day, 95% CI -61 to 28, one study) follow-up. Short breaks (one to two minutes every half hour) reduced time spent sitting at work on average by 40 minutes per day (95% CI -66 to -15, one study, low-quality evidence) compared to long breaks (two 15-minute breaks per workday) at short-term follow-up.Information and counsellingProviding information, feedback, counselling, or all of these resulted in no significant change in time spent sitting at work at short-term follow-up (MD -19 minutes per day, 95% CI -57 to 19, two studies, low-quality evidence). However, the reduction was significant at medium-term follow-up (MD -28 minutes per day, 95% CI -51 to -5, two studies, low-quality evidence).Computer prompts combined with information resulted in no significant change in sitting time at work at short-term follow-up (MD -10 minutes per day, 95% CI -45 to 24, two studies, low-quality evidence), but at medium-term follow-up they produced a significant reduction (MD -55 minutes per day, 95% CI -96 to -14, one study). Furthermore, computer prompting resulted in a significant decrease in the average number (MD -1.1, 95% CI -1.9 to -0.3, one study) and duration (MD -74 minutes per day, 95% CI -124 to -24, one study) of sitting bouts lasting 30 minutes or more.Computer prompts with instruction to stand reduced sitting at work on average by 14 minutes per day (95% CI 10 to 19, one study) more than computer prompts with instruction to walk at least 100 steps at short-term follow-up.We found no significant reduction in workplace sitting time at medium-term follow-up following mindfulness training (MD -23 minutes per day, 95% CI -63 to 17, one study, low-quality evidence). Similarly a single study reported no change in sitting time at work following provision of highly personalised or contextualised information and less personalised or contextualised information. One study found no significant effects of activity trackers on sitting time at work.Multi-component interventions Combining multiple interventions had significant but heterogeneous effects on sitting time at work (573 participants, three studies, very low-quality evidence) and on time spent in prolonged sitting bouts (two studies, very low-quality evidence) at short-term follow-up.

AUTHORS' CONCLUSIONS

At present there is low-quality evidence that the use of sit-stand desks reduce workplace sitting at short-term and medium-term follow-ups. However, there is no evidence on their effects on sitting over longer follow-up periods. Effects of other types of interventions, including workplace policy changes, provision of information and counselling, and multi-component interventions, are mostly inconsistent. The quality of evidence is low to very low for most interventions, mainly because of limitations in study protocols and small sample sizes. There is a need for larger cluster-RCTs with longer-term follow-ups to determine the effectiveness of different types of interventions to reduce sitting time at work.