The obesity epidemic affects all high‐income countries as well as middle‐income and even low‐income countries.10
This has occurred because of a persistent positive energy balance that may be as little as 100 kcal/day.8
This energy imbalance reflects nutritional excess plus low levels of physical activity.7
Low levels of physical activity result from low participation in formal exercise, such as going to the gym,11
and from low levels of non‐exercise habitual activity.12,13
The energy expended in association with non‐exercise activity, NEAT, is low in obesity specifically because walking activity is substantially less (>2 hours/day less) in obese than in lean individuals.5
Because the majority of the waking weekday is spent at work, it is not surprising that work is the predominant predictor of NEAT.14
Along with obesity, sedentariness at work is increasing,15,16
to a great extent because of the common use of desktop computers. By 2010 it is estimated that more than half of the workforce from developed countries will be working behind computers.6
We are therefore interested in devising and validating devices that promote physical activity in the workplace. To this end, we adapted an inexpensive, near‐silent, low‐impact, commercially available stepping device that can be housed under the standard work desk and can be plugged into a standard office PC for self‐monitoring. Our primary hypothesis was that the office‐place stepping device was associated with significant and substantial increases in energy expenditure compared to sitting energy expenditure. We demonstrated that using the office‐place stepping device was associated with a significant and substantial increase in energy expenditure compared to sitting energy expenditure. Moreover our volunteers enjoyed using it. Were the stepping device to be used by an overweight office worker to replace 2 hours per day of office sitting and if other components of energy balance were constant, weight loss of 20 kg/year could occur.
The stepping device we describe is immediately available and so it is tenable that many desk‐based office workers could have access to such a device. Obesity is associated with decreased workforce participation17
and healthcare costs estimated, in the US alone, to be $100–200 billion/year18
and so interventions such as this might prove to be cost‐effective. Previous workplace strategies to promote physical activity have proven limited either because the activity component is too short in duration (eg, “climb the stairs” or “walk from the car park”) or because the interventions require high levels of workforce commitment (eg, gym programmes).19,20,21
The office‐stepper device is another approach that could overcome these limitations by changing the mode of the office desk. We envisage, for example, that phone calls or document review could be performed while using the office‐stepper device which is pulled out from under the desk whenever the opportunity arises. In fact the device is sufficiently lightweight that it can be transported to meetings, conferences and seminars to convert these normally sedentary activities into active ones. We are not suggesting that the office‐stepper supersede other approaches to promote workplace activity but rather is added to them. Furthermore, we recognise that this and other approaches can only succeed to increase daily activity levels with the support of employers.
An alternative approach, to achieve the same goals as the office‐stepping device could be to place treadmills at the desk. However, treadmills are expensive, often noisy and require substantial space, although we note that the preferred exercise walking speeds were similar for the lean and obese subjects suggesting that obese subjects are not placed at a disadvantage when treadmills are made available. For the cost of one treadmill, an office could afford 10–20 under‐desk stepping devices. The stepping device we describe here, along with other supportive measures, has the potential to provide several hours of additional walking time each day to office‐based workers. Based on these data, this is equivalent to an increased energy expenditure of several hundred kcal per day. We were surprised that use of the stepping device appeared to be equivalent to or even exceed the energy expended for walking‐style exercise. This most likely reflects the fact that both activities principally involve displacing the body's weight against gravity.22
It also suggests that the stepping device could be an inexpensive option for home‐based exercise and activity.
There were several limitations to this study. The studies were short in duration and did not extend throughout the work day. For example, it is conceivable that the self‐selected stepping paces our volunteers used would slow down if the device was used throughout the work day. However, even if the individuals slowed down to half the pace they selected in these studies, they would still be dissipating 100 kcal/hour above sitting energy expenditure. We suspect that the self‐selected stepping pace is unlikely to change throughout the work day because the step rate is determined predominantly by the rate of compression of the step‐pistons so that a subsequent step occurs once the piston from the prior step is depressed. Nonetheless, we recognise this as a limitation of our study. Second, there were relatively few subjects in this study, especially if we are suggesting that the stepping device is widely applicable. Although we acknowledge this, we would point out that although the study may appear small, we were able to achieve our objectives and address our hypotheses. Our goal here was to test the feasibility of using the stepping device and also to define the energy expended in its use. A study with greater numbers would be unlikely to change our principal findings although we do recognise that further field‐testing and time‐and‐motion studies will be needed before broad‐based office application. Finally, although we demonstrated surprisingly great excursions in energy expenditure, we did not demonstrate long‐term weight loss with the use of such a device. Using the office‐stepper in weight‐loss studies is an immediate next step.
In conclusion, in this paper we described the energy expenditure associated with a simple, inexpensive, low‐impact and almost silent office‐stepper device that could allow office‐based workers to be more active throughout their work day. The stepping device was associated with significant and substantial excursions in energy expenditure above sitting. The increases in energy expenditure were equivalent to taking an exercise‐style walk. The increases in energy expenditure (200–300 kcal/hour) and tolerability of the stepping device were compatible for the lean and obese individuals. With population body weight, workplace sedentariness and healthcare costs projected to increase, interventions that allow people to work and yet be active could help reverse obesity. Thus, the office‐place stepping device was associated with similar increases in energy expenditure compared to treadmill walking despite being a tenth of the cost and size.
What is already known on this topic?
- More than half of people in high‐income countries are obese.
- Obesity is associated with low levels of daily physical activity as well as poor nutritional quality.
- New approaches are desperately needed to promote daytime physical activity.
- Since many people spend the majority of their waking hours at work, there is a growing interest in promoting workplace physical activity.
What this study adds
- We describe the energy expended while using a low‐cost stepping device that slides under a standard office desk.
- If a stepping device is used for 1 hour per day instead of sitting, energy expenditure increases by 289±102 kcal/hour.
- Since the stepping device conveniently slides under a desk, it could be used intermittently such as during telephone calls, while reading documents or during meetings.
- Such approaches may help increase daytime physical activity and reverse obesity.