Exercise as it relates to Disease/Stepping to reduce the detrimental health effects of excessive occupational sitting

This Wikibooks page is a critical appraisal of the journal article "An office-place stepping device to promote workplace physical activity" by McAlpine et al. (2007).

What is the background to this research?

Sedentary behaviour is an independent risk factor for poor health, obesity and mortality . Physical activity is associated with positive mental health and weight management benefits, as well as reduced risk of developing cardiovascular disease, hypertension, diabetes and breast and colon cancer . Lack of regular exercise and sedentary behaviour are modifiable risk factors for these biomarkers .

Prolonged sitting has been engineered into all aspects of our lives , and the predominant mode of working has become computer based resulting in sedentary occupations. Accelerometer data from a group of Australian office workers in 2013 showed that sedentary time accounted for 81.8% of work hours . Additionally, obesity is associated with decreased workforce participation. As a consequence, exploring measures to reduce sedentariness throughout the work day while preserving productivity is necessary to reduce the deleterious health effects.

This study assessed the energy expenditure of both lean and obese individuals while using an office-place stepping device and compared the exothermic effect to treadmill walking, standing, and sitting in an attempt to reduce sedentary time and increase energy expenditure.

Where is the research from?

McAlpine, Manohar, McCrady, Hensrud and Levine conducted their research at the Mayo Clinic, Rochester, USA. This study was published in the British Journal of Sports Medicine which is ranked third worldwide based on its impact, influence and prestige . Despite research taking place in the US, the findings are still relevant for Australians.

This was McAlpine's first published article prior to becoming an Emergency Medicine Physician at the Mayo Clinic . The other authors have published multiple health studies, many relating to sedentary workplace behaviour.

What kind of research was this?

This research classifies as an observational study due to the proposal of an intervention in which all subjects participated using the same methods, in the same order. It contains quasi-experimental elements as there was no random assignment. There is also a cross-sectional aspect due to the comparison between lean and obese subjects. Given the objective was to assess energy expenditure, this study design is appropriate.

What did the research involve?

The energy expenditure of 19 volunteers; nine lean and 10 obese, was measured during the below activities in the following order:

1. Lying motionless
2. Sitting in an office chair
3. Standing motionless
4. Treadmill walking at 0.5, 1, 1.5, 2, 2.5 and 3 mph (15 minutes at each speed)
5. Walking on the stepping device at a self-selected pace for 15 minutes

Activities were fixed in this order to ensure the most accurate measure of energy expended at rest.

Energy expenditure was measured using a high-precision indirect calorimeter and a full-face transparent dilution mask allowing for almost complete mobility, enabling participants to carry out regular activities with minimal disruption.

Subjects were excluded from this study if they did not meet healthy, sedentary status. However, obese subjects were still included. While I doubt the authors were implying healthy obesity can exist, it is worth noting that literature shows, compared to healthy people of a normal weight, those regarded as healthy and obese have a 49% increased risk of coronary heart disease, a 7% higher risk of stroke, and a 96% increased risk of heart failure .

What were the basic results?

After the treadmill walking segment was complete, participants were asked their preferred walking speed. This equated to 2.6 ± 0.5 mph and 2.9 ± 0.3 mph for lean and obese individuals respectively. The following comparisons show that for the group as a whole, the office-place stepping device was associated with a greater increase in energy expenditure than treadmill walking at the self-selected speed for both lean and obese participants.

	Total	Lean	Obese
Weight (kg)	85 ± 23	66 ± 13	102 ± 14
Absolute Energy Expenditure (kcal/hr)
Sitting	88 ± 21	77 ± 16	98 ± 21
Walking 2.5 mph	299 ± 77	250 ± 54	339 ± 70
Walking 3 mph	338 ± 94	275 ± 59	394 ± 85
Stepper	376 ± 116	312 ± 91	433 ± 109
Relative Energy Expenditure (kcal/kg/hr)
Sitting	1.06 ± 0.17	1.17 ± 0.09	0.96 ± 0.17
Walking 2.5 mph	3.51 ± 0.50	3.74 ± 0.48	3.30 ± 0.45
Walking 3 mph	4.00 ± 0.59	4.18 ± 0.56	3.85 ± 0.59
Stepper	4.5 ± 1.07	4.75 ± 1.06	4.26 ± 1.09

NOTE. Values are mean ± SD.

The researchers report that the increases in energy expenditure were equivalent to taking an exercise-style walk. If an obese office worker replaced sitting with the stepping device for 2 hours across the day while maintaining other components of energy balance, a 20kg/year weight reduction could occur. Incorporating stepping devices into offices may help increase physical activity and reverse obesity.

This inexpensive equipment is designed to take up minimal space and slide underneath the desk and out of the way when not in use. The idea is that the device will be used during opportune times when standing. However, it is debatable how long employees will continue to use the device once the novelty wears off. This study consisted of a small sample size, was short in duration and did not extend across an entire work day, so it is unknown how often employees would use the device.

What conclusions can we take from this research?

This study is a useful resource for employers looking to transform the current design of office desks. Since many people spend the majority of their waking hours sedentary at work, the stepper provides an inexpensive and convenient intervention. However, success relies solely on employee motivation to utilise the device. Sit-stand desks are well researched and may be a more realistic approach in decreasing sedentary behaviour initially, whilst for those already utilising a sit-stand desk or wanting to increase their incidental activity at work, a stepping device may be advantageous.

Practical advice

Further research confirming the long-term effects and consistency of use is warranted prior to broader office application. Additionally, the positive energy balance associated with obesity reflects not only low levels of physical activity, but also nutritional excess. Supplementary education around healthy food choices would likely make this intervention much more effective. Employers implementing such devices could incorporate step challenges/competitions to overcome the psychological barriers and monotony often associated with physical activity. One of the best qualities of stepping devices is their usability. Despite body weight or fitness level, almost anybody can use them, regressing or progressing pace and time of use as required.

Further reading

An evaluation of sit-stand desks in an Australian workplace

Healthy obesity?

Office work and sedentary behaviour

Heart Foundation: Sit less