Exercise as it relates to Disease/Increasing physical activity of office workers using treadmill workstations

This is a critique of the research article "Treadmill Workstations: A Worksite Physical Activity Intervention in Overweight and Obese Office Workers" by John, Thompson, Raynor, Bielak, Rider & Basset (2011).



What is the background to this research?
The World Health Organisation defines obesity as “abnormal or excessive fat accumulation that may impair health”. Clinically, an individual classified as obese has a BMI of 30.0kg/m² and above. Obesity increases the risk of developing chronic diseases including diabetes, cardiovascular diseases, and various cancers.

The number of obese individuals has more than doubled worldwide since 1980, and in 2014, more than 600 million individuals were obese. This has occurred due to the intake of energy-dense foods and sedentary behaviours including modes of transport, lifestyle, and occupations.

A study in 2014 found office and administrative occupations had the highest prevalence of obesity in the USA at 36.3%. Physical activity is an effective way to reduce obesity and more must be done to make work environments more active. This could be achieved by using active workstations. In 1989, Edelson and Danoffz first proposed the idea of using treadmill workstations (TMWS) to reduce the time office workers spent sitting. Similarly, this study looks at how TMWS impact physical activity, but also the associated health benefits.

Where is the research from?
John, Thompson, Raynor, Bielak, Rider, and Basset conducted this study at the University of Tennessee Obesity Research Centre, located in Southern USA, an area with high levels of obesity. Despite this, the research can be applied to any individual who is overweight or obese.

Of the authors involved, Basset and Raynor are well respected, contributing to over 250 and 150 publications respectively. John, while relatively new to research has conducted numerous studies into TMWS.

What kind of research was this?
This was an uncontrolled longitudinal study, with researchers conducting a series of repeated observations without a control group.

What did the research involve?
The purpose of this study was to “determine if a treadmill workstation increases physical activity and influences anthropometric, body composition, cardiovascular, and metabolic variables in overweight and obese office workers”. Researchers used an online university newsletter to recruit volunteers with the following criteria: Individuals that responded were interviewed and health screened, with 12 chosen to participate. The participants had the following characteristics:
 * Aged between 20-65
 * BMI more than 28kg/m²
 * Office space at least 49ft² (15m²)
 * Engaged in seated work most of the day
 * Able to complete 60 minutes of walking each day

A TMWS was installed in each office and participants were instructed to maintain normal physical activity and diet away from work. This was ensured using random 24-hour recalls and an accelerometer to measure physical activity. Other measurements included body composition, anthropometry, cardiovascular and metabolic variables. This was a good approach as baseline measures were compared to after the study, allowing for the effects of the TMWS to be determined.

A major limitation occurred with the small sample size (n=12). This could limit the ability to detect significant changes in variables and leaves the study susceptible to outliers. Also, the short duration of the study was a major drawback as the long-term effects of TMWS remain unclear.

What were the basic results?
The addition of the TMWS increased physical activity, having a positive effect on health. Despite this, the results show a decrease in physical activity between three and nine months due to mechanical error of the treadmills that prevented some participants from walking.

Other important results:
 * Average increase of approximately 3900 steps per day
 * Average 2.5kg weight loss
 * BMI reduction of approximately 1kg/m²
 * Waist circumference reduced by 5.5cm
 * Hip circumference reduced by 4.5cm
 * Resting heart rate decreased by 6 beats per minute
 * Decreased cholesterol levels

The researchers interpreted these results as showing TMWS are an effective way to increase physical activity and improve health. This is an appropriate claim as physical activity increased while various aspects of health also improved. The researchers do not over-emphasise the results, instead, comparing them to previous studies, discussing similarities and differences.

Two studies published in 2012 and 2014 produced similar results with increased physical activity, weight loss, decreased hip and waist circumference, lower blood pressure and cholesterol levels. With these later studies producing similar results, the claims made by the authors that TMWS can increase physical activity and improve health were valid.

What conclusions can we take from this research?
From this study, it can be concluded that TMWS could be one way of increasing physical activity in sedentary occupations. The benefits could include weight loss, lower blood pressure and cholesterol to name a few. However, obesity is often contributed to by excess energy consumption in the diet, another issue that must be addressed. Therefore, future studies should incorporate diet modifications to see further results.

Practical advice
Although this study indicates that TMWS (or active workstations) can increase physical activity, they may not be practical for most workplaces as they require a large amount of space and are expensive. In the absence of active workstations, more can be done to make workplaces more active. This could be achieved by providing a small worksite gym, standing desks or lunch fitness classes for example. When introducing physical activity, it is important to start off slowly and build up the duration and intensity to prevent injury. As occupations become increasingly sedentary, it is vital to increase physical activity to slow the rise of obesity.