https://orcid.org/0000-0003-0455-3086
Abstract
Objectives: Office workers represent one of the most sedentary groups. Alarmingly, more than one-third of their sitting time during workdays occurs in prolonged bouts. Sit-stand desk (SSD) interventions have been found to be effective in reducing sitting time, but heterogeneity exists amongst studies, which may be due to compensations outside the workplace. This study aimed to assess the impact of a 6-month SSD intervention on office workers’ sitting and standing times during the work shift and outside work (leisure time).
Methods: A 2-arm (1:1) clustered randomized controlled trial was conducted with 38 participants randomly assigned to either the intervention or control group. The intervention included a psychoeducational session, motivational prompts, and environmental modification (SSD implemented in the workplace). The waiting-list control group maintained the usual work conditions and only received the initial session. We employed repeated measures analysis of covariance to compare changes between groups while adjusting for relevant covariates, with significance set at 5%.
Results: In the intervention group, there was a significant reduction in sitting time at work by 32.97 minutes, along with a notable increase in standing time by 27.88 minutes (P < .05). Although nonsignificant (P > .05), there was an increase in sitting time in the leisure context of about 23.07 minutes.
Conclusions: This study underscores the effectiveness of SSD as a key strategy to mitigate sitting time among office workers. However, future interventions should consider integrating comprehensive behavioral strategies beyond the workplace to sustain potential increases in sitting time during leisure time and avoid compensatory behaviors.
1. Introduction
Sedentary behavior (SB) has seen a significant rise over the past decade and is responsible for approximately 1.9 million deaths globally.1 Excessive SB is difficult to define due to the lack of a specific threshold, but there are indications that from 7.5 to 9.5 hours or more has been associated with increased mortality risk.2 Adults typically accumulate sitting time (ST) (ie, an indicator of SB) in 3 domains: in the workplace, during leisure time (eg, at home in front of a television), and for transport,3 and although there are few studies on the prevalence of specific SB domains, some studies indicate that occupational SB is the more prevalent.4
Office workers typically spend a significant portion of their workday seated at their desks.5 For example, a study found that office workers spent, on average, 79% of working hours sitting, more than half of which were in prolonged sitting (≥30-minute bouts).6 This amount of SB, compounded by insufficient physical activity, exposes many workers to intensified risk of noncommunicable diseases and premature mortality.7 Occupational SB has also been explicitly linked to elevated risk of diabetes, mortality,8 and musculoskeletal issues such as neck and shoulder discomfort.9 Moreover, extensive SB detrimentally impacts crucial work-related outcomes such as engagement10 and presenteeism.11 The World Health Organization defines overweight as a body mass index (BMI) between 25 and 29.9 kg/m2, whereas obesity is classified as a BMI ≥30 kg/m2. There is evidence that longer ST is directly associated with adiposity in office workers but not in non–office workers,12 which can be attributed to different patterns of ST accumulation.12 Interestingly, these associations disappear in those workers who were sufficiently physically active during leisure time.12
SB in leisure time has been the domain most associated with deleterious mental health, especially among inactive people.13 Since office workers exhibit high levels of SB, interventions have emerged focusing on reducing ST in the workplace.8,9 Interventions incorporating sit-stand desks (SSDs) alongside multifaceted strategies are often implemented to target SB, aiming to simultaneously increase standing time.10,11
Evidence analyzing the impact of SB reduction interventions during working hours8,14,‑17 shows that SSD-based interventions can significantly reduce ST in the workplace by 6 to 120 min/d. Therefore, SSD is considered a potential strategy to reduce ST and increase standing time among office workers.14,18,19 Current recommendations suggest replacing 2 hours of ST in an 8-hour workday with standing or light activity, along with frequent posture changes.20
However, although SSDs can effectively lower SB in the workplace, it is unclear whether this reduction is maintained outside of work, or if individuals somehow compensate after working hours by increasing SB in their leisure time.21,22 One of the few studies conducted to examine the use of SSDs at work and the potential compensation effect outside work concluded that a 3-month SSD intervention with healthy workers resulted in a 20% reduction in SB during working hours; however, there was an 8% increase in SB outside work.22
Thus, although some SSD interventions suggest effectiveness in reducing 24-hour-based SB among office workers, some heterogeneity exists amongst interventions, and it remains unclear whether individuals maintain this reduction outside the workplace or if they compensate during their leisure time by increasing ST.21,22 Given the lack of literature on this topic, this study aimed to evaluate the effectiveness of a 6-month SSD intervention on office workers’ sitting time at work and analyze its impact in their leisure time.
2. Methods
2.1. Study design
This study is an ancillary analysis of data derived from a randomized controlled trial (RCT). The primary trial adhered to the Consolidated Standards of Reporting Trials (CONSORT) guidelines for cluster randomized clinical trials and it was designed as a 2-arm (1:1) parallel randomized controlled trial. Assessments were conducted at baseline and 6 months later. The entire protocol has been previously published for detailed information.23 In summary, after the initial measurements, cluster randomization was performed using a random list generator (www.random.org) by a researcher not involved in the recruitment or data collection processes. Recruitment occurred between December 2022 and January 2023, with baseline data collected in February 2023 and follow-up data gathered in August 2023. For these analyses, data were reanalyzed in 2024. The trial was registered in OSF, with the number OSF.IO/JHGPW, in November 2022.
2.2. Setting and participants
Detailed information on recruitment has been previously described,23 but in summary, office workers were recruited through university promotions, such as banners, posters, and emails sent within the institution. Before entering the trial, each participant was given a detailed oral and written study description. Participants had the opportunity to ask questions before providing written informed consent. All participants signed an informed consent form.
Researchers evaluated the workspaces of interested participants to ensure they were suitable for installing the SSD. The inclusion criteria required participants to work at least 0.6 full-time equivalent, be over 20 years old, and spend at least 70% of their week on desk-related tasks. Exclusion criteria included current SSD usage, insufficient personal space for desk setup, and musculoskeletal or health conditions that would make standing difficult. Additionally, individuals who worked from home were excluded due to the logistical challenges of providing 2 SSDs for each participant. Of the 38 participants included in the study, the majority (30 participants) had a working schedule between 9:00 am and 5:00 pm, 7 participants had a schedule from 10:00 am to 6:00 pm, and only 1 participant had a schedule from 2:45 pm to 10:45 pm.
2.3. Data collection
An online questionnaire, administered in person with the assistance of research team members, was used to collect information on the participants’ sociodemographic profiles, health conditions, and work-related characteristics. In accordance with ethical guidelines, the data from this study were securely stored in a restricted-access folder, accessible only to the research team. Participants’ consent did not include permission to share these data publicly.
2.4. Interventions
In summary, participants in the intervention group attended an initial psychoeducational session and were provided with an SSD (Vinsetto, Model 923-043). The intervention included assembling the SSD at participants’ desks before the start of the program. Participants received personalized instructions on the desired progression of SSD use, ergonomic posture advice, and individualized support to increase standing time gradually.
Motivational nudges were integrated throughout the intervention to address potential disruptions to new routines, such as holidays. These efforts aimed to enhance relatedness, perceived competence, and autonomy, consistent with self-determination theory,24 to encourage autonomous motivation for sustained behavior change.25 The session aimed to increase awareness and understanding, as similar approaches have effectively promoted behavior change.26
The waiting-list control group only participated in the same psychoeducational session, with no changes in the work environment.
2.5. Main outcomes
The time spent sitting, standing, and stepping were objectively measured at baseline and 6 months later. Participants were instructed to continuously wear an ActivPAL4 activity monitor (PAL Technologies Ltd, Glasgow, UK) for 24 h/d over 7 days. The detailed methodology for this assessment has been previously published.23 For these analyses, we focused on 3 specific variables: ST, standing time, and stepping time, both during work and in leisure time, using the valid monitored days and the specific working schedules of each participant.
We decided to present the ActivPAL data in percentages instead of minutes, to be clearer and easily comparable with previous data. To calculate the percentages of time spent sitting and standing during work and in leisure time, as presented in Figure 1, we used 24 hours as the basis. We divided the time spent in each activity (sitting or standing) by 24 hours and multiplied by 100 to obtain the corresponding percentage. We applied the same rationale to calculate the ratio of time explicitly spent at work, dividing the time by 8 hours and multiplying by 100 to obtain the corresponding percentage.
Sitting and standing times at work and leisure at baseline and 6 months for both groups.
2.6. Assessment procedures
Assessment procedures have been detailed in a prior publication.23 A trained assessor gave participants the device attached to the midpoint of their right thigh using a waterproof medical dressing. Participants were instructed to wear the device continuously for 7 consecutive days. Subsequently, participants filled out an online questionnaire, with a trained assessor available to help with any questions. This questionnaire was developed using Qualtrics online software and addressed various topics as previously described.23
The data collected by ActivPAL were analyzed by summing the hourly information generated by the ActivPAL software for the period in which each participant was at work and outside work. This means that 38 × 6 × 2 × 3 × 2 (ie, participants × full days × work vs leisure × variables × baseline vs 6-month) periods were manually calculated based on the hourly data and the actual working shift for each participant, which translates into 2736 calculated units, allowing us to accurately identify and quantify the time spent sitting, standing, and stepping, both in the work environment and during leisure time.
2.7. Secondary outcomes
Participants were weighed while wearing minimal clothes and without shoes on an electronic scale (TANITA BC-601 scale). Height was measured with a stadiometer (Seca, Hamburg, Germany). BMI was calculated as body mass (kg)/height2 (m).
2.8. Sample size
Considering the type of investigation (clustered RCT) and primary outcome of the intervention (ie, ST) while using an effect size of 0.80, the total number of participants for between-group analyses, with a power of 0.80 and a significance level of .05 (2-tailed test), would have been 34 participants.
2.9. Statistical analyses
Statistical analyses were conducted using PASW Statistics version 29.0.2.0 (SPSS Inc, Chicago, IL, USA). Independent-sample t tests were used to compare groups at baseline and 6 months. A repeated measures analysis of covariance was performed, with time (baseline vs 6-month) as the within-subject factor and the intervention group as the between-subject factor, to evaluate time × group interaction effect on the outcomes. The significance level was set at 5%.
3. Results
This study included 38 participants, evenly distributed with 19 in each group. Table 1 provides an overview of the baseline characteristics of the Stand Up for Healthy Aging (SUFHA) study participants.
Baseline characteristics by group: control and intervention.a
| Characteristics | Control | Intervention | Total |
|---|---|---|---|
| Sample size | n = 19 | n = 19 | n = 38 |
| Age, y | 42.3 (9.5) | 45.3 (6.0) | 43.8 (8.0) |
| Women, n (%) | 14 (73.3%) | 16 (80.0%) | 30 (76.6%) |
| Biometric measurements | |||
| Body mass index, kg/m2 | 30.5 (7.4) | 27.2 (6.1) | 28.8 (6.9) |
| Body weight, kg | 82.3 (21.1) | 72.0 (16.5) | 77.0 (19.4) |
| Height, m | 1.64 (0.1) | 1.63 (0.1) | 1.63 (0.1) |
| Characteristics | Control | Intervention | Total |
|---|---|---|---|
| Sample size | n = 19 | n = 19 | n = 38 |
| Age, y | 42.3 (9.5) | 45.3 (6.0) | 43.8 (8.0) |
| Women, n (%) | 14 (73.3%) | 16 (80.0%) | 30 (76.6%) |
| Biometric measurements | |||
| Body mass index, kg/m2 | 30.5 (7.4) | 27.2 (6.1) | 28.8 (6.9) |
| Body weight, kg | 82.3 (21.1) | 72.0 (16.5) | 77.0 (19.4) |
| Height, m | 1.64 (0.1) | 1.63 (0.1) | 1.63 (0.1) |
Values are mean (SD) except for gender distribution.
Baseline characteristics by group: control and intervention.a
| Characteristics | Control | Intervention | Total |
|---|---|---|---|
| Sample size | n = 19 | n = 19 | n = 38 |
| Age, y | 42.3 (9.5) | 45.3 (6.0) | 43.8 (8.0) |
| Women, n (%) | 14 (73.3%) | 16 (80.0%) | 30 (76.6%) |
| Biometric measurements | |||
| Body mass index, kg/m2 | 30.5 (7.4) | 27.2 (6.1) | 28.8 (6.9) |
| Body weight, kg | 82.3 (21.1) | 72.0 (16.5) | 77.0 (19.4) |
| Height, m | 1.64 (0.1) | 1.63 (0.1) | 1.63 (0.1) |
| Characteristics | Control | Intervention | Total |
|---|---|---|---|
| Sample size | n = 19 | n = 19 | n = 38 |
| Age, y | 42.3 (9.5) | 45.3 (6.0) | 43.8 (8.0) |
| Women, n (%) | 14 (73.3%) | 16 (80.0%) | 30 (76.6%) |
| Biometric measurements | |||
| Body mass index, kg/m2 | 30.5 (7.4) | 27.2 (6.1) | 28.8 (6.9) |
| Body weight, kg | 82.3 (21.1) | 72.0 (16.5) | 77.0 (19.4) |
| Height, m | 1.64 (0.1) | 1.63 (0.1) | 1.63 (0.1) |
Values are mean (SD) except for gender distribution.
The participants ranged from 24 to 60 years old and predominantly consisted of females (76.3%). At the beginning of the study, no differences were observed between the intervention and control groups (P > .05), except for stepping in leisure time (see Table 2), which was 15 minutes higher in the intervention group (P = .038). At baseline, 1 participant was underweight, 13 participants were classified as normal weight, 10 participants were overweight, and 14 participants were obese.
Sitting, standing, and stepping at work and leisure, baseline and 6 months, for both groups.
| Outcomes | Mean (SD) at baseline, min | Mean (SD) at 6 mo, min | P value | Mean difference from baseline to 6 mo (95% CI), min | |||||
|---|---|---|---|---|---|---|---|---|---|
| CG (n = 19) | IG (n = 19) | CG (n = 19) | IG (n = 19) | Time × group | CG (n = 19) | Time P value | IG (n = 19) | Time P value | |
| Sitting time work | 332.27 (95.67) | 357.18 (79.38) | 328.47 (106.39) | 324.21 (89.86) | .083 | −3.80 (−16.19 to 23.78) | .695 | −32.97 (−60.97 to −4.98) | .024a |
| Standing time work | 112.94 (55.79) | 113.70 (71.06) | 119.97 (85.28) | 141.58 (80.76) | .239 | 7.03 (−22.14 to 36.20) | .619 | 27.88 (5.83 to 49.94) | .016a |
| Stepping time work | 39.31 (13.17) | 40.73 (12.58) | 42.60 (25.38) | 40.38 (13.21) | .438 | 3.29 (−12.34 to 5.77) | .456 | −0.35 (−0.39 to 3.19) | .839 |
| Sitting leisure | 143.60 (78.30) | 114.21 (66.13) | 156.03 (79.76) | 137.28 (60.67) | .658 | 12.43 (−26.11 to 50.97) | .507 | 23.07 (−8.98 to 55.11) | .148 |
| Standing leisure | 135.42 (56.67) | 164.59 (68.27) | 116.64 (52.17) | 142.66 (58.17) | .859 | −18.78 (−43.55 to 5.98) | .128 | −21.93 (−49.38 to 5.53) | .111 |
| Stepping leisure | 42.17 (19.42) | 57.25b (23.47) | 44.16 (24.55) | 57.78 (20.91) | .857 | 1.99 (−9.67 to 13.65) | .724 | 0.53 (−11.70 to 12.76) | .928 |
| Outcomes | Mean (SD) at baseline, min | Mean (SD) at 6 mo, min | P value | Mean difference from baseline to 6 mo (95% CI), min | |||||
|---|---|---|---|---|---|---|---|---|---|
| CG (n = 19) | IG (n = 19) | CG (n = 19) | IG (n = 19) | Time × group | CG (n = 19) | Time P value | IG (n = 19) | Time P value | |
| Sitting time work | 332.27 (95.67) | 357.18 (79.38) | 328.47 (106.39) | 324.21 (89.86) | .083 | −3.80 (−16.19 to 23.78) | .695 | −32.97 (−60.97 to −4.98) | .024a |
| Standing time work | 112.94 (55.79) | 113.70 (71.06) | 119.97 (85.28) | 141.58 (80.76) | .239 | 7.03 (−22.14 to 36.20) | .619 | 27.88 (5.83 to 49.94) | .016a |
| Stepping time work | 39.31 (13.17) | 40.73 (12.58) | 42.60 (25.38) | 40.38 (13.21) | .438 | 3.29 (−12.34 to 5.77) | .456 | −0.35 (−0.39 to 3.19) | .839 |
| Sitting leisure | 143.60 (78.30) | 114.21 (66.13) | 156.03 (79.76) | 137.28 (60.67) | .658 | 12.43 (−26.11 to 50.97) | .507 | 23.07 (−8.98 to 55.11) | .148 |
| Standing leisure | 135.42 (56.67) | 164.59 (68.27) | 116.64 (52.17) | 142.66 (58.17) | .859 | −18.78 (−43.55 to 5.98) | .128 | −21.93 (−49.38 to 5.53) | .111 |
| Stepping leisure | 42.17 (19.42) | 57.25b (23.47) | 44.16 (24.55) | 57.78 (20.91) | .857 | 1.99 (−9.67 to 13.65) | .724 | 0.53 (−11.70 to 12.76) | .928 |
Abbreviations: CG, control group; IG, intervention group.
Significant time effect within group.
Significant differences between groups at baseline based on the independent sample t test.
Sitting, standing, and stepping at work and leisure, baseline and 6 months, for both groups.
| Outcomes | Mean (SD) at baseline, min | Mean (SD) at 6 mo, min | P value | Mean difference from baseline to 6 mo (95% CI), min | |||||
|---|---|---|---|---|---|---|---|---|---|
| CG (n = 19) | IG (n = 19) | CG (n = 19) | IG (n = 19) | Time × group | CG (n = 19) | Time P value | IG (n = 19) | Time P value | |
| Sitting time work | 332.27 (95.67) | 357.18 (79.38) | 328.47 (106.39) | 324.21 (89.86) | .083 | −3.80 (−16.19 to 23.78) | .695 | −32.97 (−60.97 to −4.98) | .024a |
| Standing time work | 112.94 (55.79) | 113.70 (71.06) | 119.97 (85.28) | 141.58 (80.76) | .239 | 7.03 (−22.14 to 36.20) | .619 | 27.88 (5.83 to 49.94) | .016a |
| Stepping time work | 39.31 (13.17) | 40.73 (12.58) | 42.60 (25.38) | 40.38 (13.21) | .438 | 3.29 (−12.34 to 5.77) | .456 | −0.35 (−0.39 to 3.19) | .839 |
| Sitting leisure | 143.60 (78.30) | 114.21 (66.13) | 156.03 (79.76) | 137.28 (60.67) | .658 | 12.43 (−26.11 to 50.97) | .507 | 23.07 (−8.98 to 55.11) | .148 |
| Standing leisure | 135.42 (56.67) | 164.59 (68.27) | 116.64 (52.17) | 142.66 (58.17) | .859 | −18.78 (−43.55 to 5.98) | .128 | −21.93 (−49.38 to 5.53) | .111 |
| Stepping leisure | 42.17 (19.42) | 57.25b (23.47) | 44.16 (24.55) | 57.78 (20.91) | .857 | 1.99 (−9.67 to 13.65) | .724 | 0.53 (−11.70 to 12.76) | .928 |
| Outcomes | Mean (SD) at baseline, min | Mean (SD) at 6 mo, min | P value | Mean difference from baseline to 6 mo (95% CI), min | |||||
|---|---|---|---|---|---|---|---|---|---|
| CG (n = 19) | IG (n = 19) | CG (n = 19) | IG (n = 19) | Time × group | CG (n = 19) | Time P value | IG (n = 19) | Time P value | |
| Sitting time work | 332.27 (95.67) | 357.18 (79.38) | 328.47 (106.39) | 324.21 (89.86) | .083 | −3.80 (−16.19 to 23.78) | .695 | −32.97 (−60.97 to −4.98) | .024a |
| Standing time work | 112.94 (55.79) | 113.70 (71.06) | 119.97 (85.28) | 141.58 (80.76) | .239 | 7.03 (−22.14 to 36.20) | .619 | 27.88 (5.83 to 49.94) | .016a |
| Stepping time work | 39.31 (13.17) | 40.73 (12.58) | 42.60 (25.38) | 40.38 (13.21) | .438 | 3.29 (−12.34 to 5.77) | .456 | −0.35 (−0.39 to 3.19) | .839 |
| Sitting leisure | 143.60 (78.30) | 114.21 (66.13) | 156.03 (79.76) | 137.28 (60.67) | .658 | 12.43 (−26.11 to 50.97) | .507 | 23.07 (−8.98 to 55.11) | .148 |
| Standing leisure | 135.42 (56.67) | 164.59 (68.27) | 116.64 (52.17) | 142.66 (58.17) | .859 | −18.78 (−43.55 to 5.98) | .128 | −21.93 (−49.38 to 5.53) | .111 |
| Stepping leisure | 42.17 (19.42) | 57.25b (23.47) | 44.16 (24.55) | 57.78 (20.91) | .857 | 1.99 (−9.67 to 13.65) | .724 | 0.53 (−11.70 to 12.76) | .928 |
Abbreviations: CG, control group; IG, intervention group.
Significant time effect within group.
Significant differences between groups at baseline based on the independent sample t test.
Table 2 shows the time differences observed in the intervention group for ST at work, showing a reduction of 32.97 min/workday (P = .024), and for standing time at work, indicating an increase of 27.88 min/workday (P = .016). The control group had no time differences (P > .05). Despite the differences in the intervention group and the nonsignificant differences in the control group, there was no time × group interaction effect for the different outcomes (P > .05), neither in the work setting nor in leisure time.
Finally, although nonsignificant, in the intervention group we observed an increase in ST of approximately 23 minutes and a decrease in standing time of about 22 minutes in the leisure setting, which also happened in the control group in a more attenuated manner, with an increase of 12.43 minutes in sitting time and a decrease of 18.78 minutes in standing time in the leisure setting.
Figure 1 shows the interindividual variability in response to the intervention, both in the work and leisure contexts, for both groups. At the beginning of the intervention, the percentage of ST at work was over 60% for the control and intervention groups, with values of 61.53% and 62.42%, respectively. After 6 months, the control group showed a slight reduction in ST, but the average remained above 60% (60.83%). In contrast, the intervention group showed a more significant reduction, with the average working ST dropping to 57.32%.
4. Discussion
This study examined the effectiveness of a 6-month SSD intervention in reducing office workers’ ST during working hours and in their leisure time. Our results indicated significant reductions in ST and increased standing time at work, only in the intervention group (P < .05). Although no time × group interaction effect was found, there was an approximate difference of 30 minutes per workday between the intervention and control groups, consistent with previous research findings.27,28 The reduction in ST in the intervention group can be attributed to the combination of SSD with multifaceted strategies, as multicomponent interventions involving SSDs seem to consistently reduce ST of office workers.29,30 For example, a systematic review of multicomponent SSD interventions in the workplace supports this observation by reporting an average decrease of 29.96 min/d,16 which is like the reduction found in our intervention.
Although not statistically significant, an increase in sitting during leisure time was observed in the intervention group (23.07 minutes). This result aligns with a previous study,22 which documented an increase in sitting during leisure time 3 months after the implementation of new workstations. Additionally, the control group also experienced a nonsignificant compensatory increase in ST of 12.43 minutes during leisure hours, suggesting that both groups adapted their behavior in response to alterations in their daily sitting patterns. Research conducted by Ball et al31 has demonstrated that behavioral changes can be driven by social influences, environmental cues, and the perception of colleagues’ behaviors, even without direct intervention. This highlights the critical need to consider leisure activities when evaluating the overall impact of interventions to reduce SB.
The increase in sitting during leisure time is concerning as it can be associated with adverse effects on the well-being of employed adults,32 including increased depressive symptoms, perceived stress, and anxiety.33,34 The observed increase in sitting during leisure time may be partially attributed to fatigue or discomfort experienced later in the day, which may have negatively influenced the overall effectiveness of the intervention.35 Stephens et al36 highlighted that the positive impact of interventions was more pronounced earlier in the day, with decreasing effects observed as the day progressed, likely due to worker fatigue or muscle discomfort. This pattern is supported by qualitative research, which reveals a preference for standing in the morning that diminishes throughout the day.37 Therefore, fatigue and discomfort later in the day may have played a significant role in the increased ST in the outside-work hours in both the control and intervention groups.
This is not the first time an SSD intervention does not result in an interaction effect between groups. A study by Renaud et al17 did not find a reduction in ST at work from baseline to 4 months. In fact, the difference between the intervention and control groups after 4 months of follow-up was only −16.2 minutes per workday.17 The absence of effects during specific intervention periods can be attributed to the prevalent sitting culture in most office environments.17 A study that combined qualitative and quantitative methods38 found that the social environment, particularly the presence and actions of colleagues, influences workers’ behavior regarding standing at work. Seeing colleagues working while standing motivated others to do the same, although some workers mentioned feeling insecure, which led them to remain seated.38
A relevant factor to consider is that the average BMI of participants in both the intervention and control groups at baseline was within the overweight category (28.8 kg/m2). Individuals with overweight or obesity tend to spend more time sitting, which can be partially attributed to difficulties in engaging in more standing time and lower motivation to adopt active behaviors.39 However, our sample’s BMI varied from 16.28 to 46.63 kg/m2, meaning that although the average BMI was within the overweight category, we included participants with normal weight and even underweight, so these results are expected in office workers with normal or underweight body types. Moreover, considering that our sample consisted of sedentary office workers, it is natural that a higher percentage of individuals presented overweight or obesity (ie, 63%), which must be recognized as a factor that could have contributed to the lower reduction of ST in the workplace found in the current investigation, compared with previous interventions.28,40
It is important to note that although there was no time × group interaction in the present study, these results may be relevant for various outcomes. Previous studies have indicated that replacing 30 minutes of ST with physical activity of any intensity is associated with a lower risk of several cardiovascular disease indicators and all-cause mortality,41 as well as lower levels of depressive symptoms,42 which can be clinically relevant. Our intervention is consistent with the study conducted by Edwardson et al.28,40 With a duration of 6 months, that intervention employed multifaceted organizational, environmental, and individual strategies and reduced ST during working hours by 68.34 min/workday. However, the study also revealed an increase in ST during leisure periods of 25.96 min/d, thus corroborating our results and suggesting that when office workers reduce their ST at work, some compensation seems to occur in their leisure time, by increasing this behavior. Thus, we believe that besides the accumulated fatigue or discomfort throughout the day, the lower effectiveness of some SSD interventions may also be explained by a psychological mechanism, in which some individuals rely on the reduction they attained during the work shift and compensate by being more sedentary in the outside-work setting.
As depicted in Figure 1, although some individuals showed a reduction in ST while at work, there were cases of increasing ST at work from baseline to the end of the intervention. Additionally, variability in standing time was also observed, further highlighting the differential impact of the intervention across participants. Previous studies usually report the mean and SD of a group, but showing the individual heterogeneity in the response to this type of intervention is paramount, so that future studies can focus on the individual response to SSD interventions and explore potential mediators of effectiveness. In this way, one must tailor the best strategy that can be applied to each office worker. Further studies on this issue are needed to verify participant variability in response to SSD-based interventions.
These findings underscore the importance of extending behavioral interventions beyond the workplace to achieve sustained reductions in SB. Educating individuals about the long-term benefits of reducing SB and providing tools like activity trackers during leisure time can further enhance intervention effectiveness.43
4.1. Strengths and limitations
The study presented several strengths. Firstly, randomizing participants into clusters minimized the risk of contamination between groups, ensuring greater internal validity of the study. Secondly, physical behaviors were objectively measured using ActivPAL4 activity monitors, providing precise and reliable data on sitting, standing, and stepping times. The intervention included an initial psychoeducational session and continuous motivational stimuli to promote sustained behavioral change.
However, the study also had some limitations. The study population was predominantly female, which may limit the applicability of the results to a more gender-balanced or male-dominated workforce. Additionally, the 6-month follow-up period, although helpful in assessing initial changes, may not be sufficient to evaluate the long-term sustainability of the observed behavioral changes. Another point is that, although the sample included underweighted, normal-weighted, and overweighted office workers, the sample size prevents secondary analysis depicting the results amongst groups based on this feature, and naturally we had a higher percentage of our sample with overweight or obesity. Finally, despite the clinical meaningfulness of some of our findings, the lack of significant results (eg, no time × group interaction effect) must be recognized as a limitation regarding the sample size, as a higher number of participants could have diluted the large variability amongst participants in response to the intervention. Future studies including larger sample sizes may explore the weight category as a potential mediator of effectiveness for the SSD-based interventions.
4.2. Implications for practice
To optimize interventions aiming to reduce ST and promote standing, it is essential to extend these actions beyond the workplace. Encouraging exercise during leisure time can be facilitated through wellness programs, such as walking challenges, which help integrate light-intensity physical activity into employees’ daily routines.
5. Conclusions
We demonstrated that a 6-month intervention using an SSD significantly reduced office workers’ ST while increasing standing time during working hours. However, these findings underscore the potential compensatory behaviors that may also exist amongst participants (ie, increasing ST and reducing standing time in their leisure time) that researchers must be aware of, even for an accurate assessment of the actual changes in physical behaviors. We highlighted that considering a 24-hour period may not translate the modifications that genuinely occurred.35 Finally, extending behavioral strategies beyond the workplace to maximize health benefits in future interventions is crucial. Further research is needed to assess the long-term sustainability of SSD interventions in different occupational contexts and to explore their scalability in diverse settings. These efforts are essential for promoting healthier workplaces and reducing the global impact of noncommunicable diseases.
Acknowledgments
We want to thank the participants for their time and effort. The study received approval from the ethics committee of the Universidade Lusófona, with approval number D0522. It was conducted following the Declaration of Helsinki for Human Studies.
Author contributions
P.B.J. conceptualized the study. P.B.J., H.S., and S.C.T. developed the methodology. H.S. wrote the original draft, and S.C.T. and P.B.J. reviewed and edited the manuscript. All authors have read and agreed to the published version of the manuscript. While preparing this manuscript, the authors employed Grammarly’s AI-driven writing tool to enhance the language and readability. Afterwards, they meticulously reviewed and revised the text, taking full responsibility for the final version of the publication.
Funding
This study was funded by the ILIND “Fazer+” scientific program (reference: FAZER+/ILIND/CIDEFES/1/2022). The funder had no role in the study regarding the design, data collection, management, analysis, and interpretation.
Conflicts of interest
The authors declare that they have no competing interests.
Data availability
Anonymized trial data will be made available exclusively for noncommercial research purposes upon request to the principal investigator.
