Exercise as it relates to Disease/Workplace revolution; method to engage adults in physical activity during their working hours
This page reviews and critiques the article: "Multicomponent intervention to reduce daily sedentary time: a randomised controlled trial" by Carr, L., Karvinen, K., Peavler, M., Smith, R. and Cangelosi, K. (2013).
What is the background to this research?
Physical inactivity is the fourth leading cause of death worldwide  and associated with many health risks such as type 2 diabetes , cardiovascular disease , metabolic syndrome , obesity  and all-cause mortality . However, the majority of the population in modern society do not meet the daily recommended physical activity guidelines , and most sedentary workers are shown to spend almost 77% of their working hours sedentary .
The purpose of the present study was using a multicomponent intervention to promote sedentary adults working in sedentary jobs to engage in more physical activity, or ‘active sitting’ during their working hours. Because modern full-time workers spend almost a third of their day at work, reducing their time spent sedentary during this time period will have a significant influence on their health and well-being. A meta-analysis study conducted in 2015 has shown that prolonged sedentary time was independently associated with deleterious health outcomes regardless of physical activity . This strongly suggests that people who participate in regular physical activity during their leisure time can still be at risk if they remain sedentary during their working hours.
The research was a randomised controlled trial meaning that the subjects were chosen at random to minimise bias. The participants were divided into two groups of either being an intervention group or a wait-list control group. Over 5392 participants of all races and ethnic backgrounds working at a large southern university in the US were passively recruited using email advertisements. A total of 192 people responded and of which 143 were excluded from participation due to their not meeting the eligibility criteria. A voluntary written informed consent was obtained from each participant as well as permissions from their work supervisors prior to enrolment. Along with Australia, the United States is one of the first-world countries with the highest prevalence of obesity and physical inactivity among their population. The subjects of this research were also chosen at random from diverse race and ethnic background to minimise bias. However, the sample size (n=40) of this research was too small, and the randomly chosen subjects were primarily middle-aged women working at a single institution and the majority reported being non-Hispanic. Therefore, the generalisability of the result is limited and may have difficulty applying this study directly to the Australian population.
Lucas Carr, the lead author of this study, is an Associate Professor in the Department of Health and Human Physiology at the University of Iowa. His main area of study is health promotion and health studies, specialised in physical activity promotion and sedentary behaviour interventions. Professor Carr has conducted many kinds of research in similar areas as this research paper, focusing on health promotion for the general population .
What did the research involve?
During the intervention, the intervention group was encouraged to reduce their time spent sedentary for 12 weeks while receiving a theory-based, internet-delivered program, a portable pedal and a pedometer at work. In contrast, the wait-list group was asked to maintain their current behaviours throughout the intervention period.
The primary and secondary outcomes were measured at baseline and post-intervention for both intervention (N=23) and wait-list (N=17) groups, and the data were compared to measure the intervention outcome. The list of primary and secondary outcomes are as follows:
- Objective measures of sedentary and physical activity through StepWatch
Secondary (Cardiometabolic risk factors)
- Heart rate
- Blood pressure
- Waist circumference
- Percent body fat
- Cardiorespiratory fitness
- Fasting lipids
The StepWatch device used to measure the primary outcome was specifically worn at the ankles of each participant. The accelerometer is a widely used device for measuring objective measures of physical activity, and many studies have shown that ankle-worn StepWatch is an ideal device for measuring steps , energy expenditure , pedalling time  and sedentary behaviour  compared to other accelerometers. Furthermore, Lucas Carr and his team have previously conducted research to test the feasibility of using the pedal exercise machine at the workplace  The result was positive, many participants found the machines feasible for use at work.
What were the basic results?
The intervention group was able to reduce their mean number of times spent sedentary by 58.7 min/day, while increasing their mean number of times spent on moderate-intensity physical activity by 8.8 min/day. Compared to the wait-list group, this intervention effect reached near significance for both percent daily time spent sedentary (p=0.06) and percent time spent in moderate-intensity physical activity (p=0.06). No significant intervention effect was observed for cardiometabolic risk factors besides waist circumference (p=0.03). This is probably due to the low intensity of the intervention as well as the limited duration of 12 weeks.
What conclusions can we take from this research?
The findings of this research gave us an insight that pedal machine along with the internet-based motivational program can be an effective tool in reducing sedentary behaviour for sedentary workers. Employers who were concerned about their workers' health can use this study as a useful resource for promoting a healthy working environment. The pedal machine is an inexpensive and convenient device, providing great opportunities for office workers to engage in more physical activity as this device can be used while seated. However, success relies solely on employee motivation, therefore including motivational intervention is recommended.
Participants rated the intervention as ‘extremely helpful’ for reducing their sedentary time, but many of them reported that the machine was uncomfortable in a way that their knees were hitting the underside of the desk while pedalling. This would have negatively influenced the participant’s motivation and affected the result.
It will be more interesting to see the research team monitoring the participant’s activity status after the post-intervention period to measure the persistency of their improved behaviours. Also, comparing the efficiency of the pedal machine with different interventions on promoting physical activity (sit-to-stand desk, stepper device, etc) is needed before prioritising the use of the pedal machine for reducing sedentary behaviour within the workplace.
Portable pedal machine is definitely a good strategy for reducing sedentary behaviour within workplace. To optimise the benefit, including a motivational intervention is highly recommended. When using this device, the height of the desk should be adjusted so your knees don’t hit the underside of the desk while pedaling. Interrupting bouts of sedentary behaviour is shown to help control adiposity and improve metabolic health, therefore employees are encouraged to evenly distribute their pedaling time daily. An alternative method can be used for reducing sedentary behaviour within the workplace. Sit-to-stand desk and mini stepper device are shown to be effective in reducing sedentary behaviour in the workplace as well, hence comparing the pros and cons of each methods before commencing is recommended to suit your needs.
- The Effect of Active Workstation Use on Measures of Cognition, Attention, and Motor Skill
- Impact of added rest breaks on the productivity and well being of workers
- Simple tips to reduce sedentary behaviour throughout the day
- Active Workplace Study
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