Exercise as it relates to Disease/Do walking strategies to increase activity reduce reported sitting in workplaces?

This is a critique of the research article: Gilson, N. et al.(2009) 'Do walking strategies to increase physical activity reduce reported sitting in workplaces: a randomized control trial. International Journal of Behavioral Nutrition and Physical Activity, 6(1), 43

What is the background to this research?
Move less, sit more —ubiquitous in modern society. As humans we are spending more and more time in environments that limit our physical activity while promoting sedentary behaviour such as sitting. Sedentary behaviours require very little energy expenditure, with the western population spending around 60hrs/wk sedentary. High levels of this type of behaviour is associated with an increased risk to type 2 diabetes, cardiovascular disease, obesity and death, so it's obvious we want to spend less time engaged in this behaviour. Indicative of this, studies have suggested that disrupting long periods of sitting with low intensity physical activity provides numerous health benefits.

Walking is one such activity. Generally, increasing an individuals time spend walking has been linked to lower the risk of chronic disease in sedentary individuals. The workplace could be a key area in which walking can be incorporated to promote behaviour change in sedentary individuals as it could provide numerous health benefits. The article chosen for this critique aims to determine if walking strategies can reduce sitting—a sedentary behaviour—and increase physical activity in the workplace.

Where was the research from?
The study was conducted across major regional universities in the UK, Spain and Australia.

This article was published in the International Journal of Behavioural Nutrition and Physical Activity in 2006 by Nicholas D Gilson and colleagues. Informed consent was provided by all participants and the study protocol was approved by the ethics committee of each university.

All authors declared no conflict of interest.

What kind of research was this?
The study was a randomized controlled study that used convenience sampling. Pre intervention step counts were measured over five consecutive workdays. Using those results, participants were randomly assigned to a control group (maintain normal behaviour), route-based walking group (at least 10 minutes of sustained walking each workday) and an incidental walking group (walking in workday tasks).

What did the research involve?
The purpose of this study was to see if walking strategies reduced sitting in a workplace. The participants in this study were staff from white-collar universities in the UK (n=64; age =41.4 +/- 10.4; 58 women) Australia (n=70; age=43.1 +/- 10.8; 54 women) and Spain (n=80;age 39.1 +/- 9.7; 58 women) who undertook a 10 week intervention.

Personal information which included age, gender, contact details and body mass index calculations were recorded pre-intervention. For 5 consecutive workdays, a diary and unsealed pedometer were used to record the step counts of the participants. These pedometers were used by the participants throughout the duration of the intervention. Workday sitting times (h:m) were measured by a question formatted logbook. These questions were adapted to allow for more accurate recall by the participants. Based on this pre-intervention information, the participants were randomly assigned to one of three groups.

The three groups in this study were:

-	Control group - Participants in the control group were given instructions to maintain their normal behaviour over the intervention.

-	Intervention group 1 (route-based) - Participants in the route – based walking group were given instructions to increase their step count by incorporating brisk, sustained route-based walking during work breaks.

-	Intervention group 2 (incidental) - Participants in the incidental walking group were also given instructions to increase their step count. It was suggested that this be achieved through walking and talking to colleagues face-to-face, rather than phone calls or sending emails. It was also suggested participants should stand and walk during meetings, opposed to sitting down at a table.

Importantly, the participants were told not to partake in any additional physical activities other than those in their usual routine. If they did, they were asked to report it.

Throughout the study, step counts and reported sitting time were re-assessed during week one, five and ten.

What were the basic results?
As seen in Table 1 - the results found that both intervention groups significantly increased their walking compared to the control group. Alternatively, the control group had a non-significant decrease in their step count.

- Mean ± SD and 95% confidence intervals for pre- and intervention sleep steps/day (*p < 0.05; **p < 0.001).

However, while there was a tendency for reported sitting times to decrease in the intervention groups and increase slightly in the control group (table 2), there were no significant differences in reported sitting times between the groups. Despite this non-significant change, the researchers concluded the results partially supported their hypothesis—that walking intervention can reduce sitting times.

- Mean ± SD and 95% confidence intervals for pre- and intervention sitting times (mins/day).

Limitations
The self-report method used throughout the study can impact the validity of the results. As the sample size was relatively small, the statistical power of the results could potentially be impacted.

The gender group distribution, as acknowledged by the authors, can also impact the generalisability of the results towards men and other workplaces.

What conclusions can we take from this research?
We can conclude that both intervention groups targeted by route-based and incidental walking, significantly increased their physical activity throughout the day. The researchers also concluded that the non-significant results partially supported their hypothesis. However, despite a decrease trend in the amount of time spent sitting during work hours, there isn't enough supporting evidence in this study to confidently come to this conclusion. This is highlighted through the limitations that are present—including response bias, and poor generalisability. Overall, this study provides a great base and springboard for future studies that focus on reducing sedentary behaviours in workplaces.

Practical Advice
Based on this study, there is numerous things people can take and incorporate into their life such as:

- Creating walking strategies during work to allow you to walk more throughout the day allowing 10,000 steps/day, and

- Minimise time throughout the day spend sitting, and break it up with periods of walking to decrease risk of cardiovascular disease