Exercise as it relates to Disease/Walking and working, how treadmill working stations helping obese workers lose 30 kilos a year

This is a critic of obese office workers and a walk and work treadmill intervention. This has been written as a university assignment for the University of Canberra for the unit: Health, Disease and Exercise.

The paper: Levine, J. A., & Miller, J. M. (2007). The energy expenditure of using a “walk-and-work” desk for office workers with obesity. British Journal of Sports Medicine, 41(9), 558–561.



What is the background to this research?
As technology advances it correlates with the nature of work becoming more fixated on a computer screen, resulting in societies increasingly sedentary behavior - Sedentary behavior, often thought as sitting time, refers to low energy expenditure behaviors of less than 1.5 METs. Between 1950 and 2000 the percentage of American Adults employed in high activity occupations declined 33% while the amount of adults in sedentary jobs raised 76%. Studies show obese individuals sit over 2 ½ hours more daily than those of lean individuals. Creating a lifestyle trend that has been shown to lead to Obesity,  metabolic syndrome,  cardiovascular disease  and colon cancer.

The purpose of this study is to develop a healthy workplace initiative with the hypothesis; would a treadmill that can attach to a regular office desk and used daily during 2-4 work hours cause a significant increase on energy expenditure in comparison to sitting in an office chair?

Where is the research from?
The Study by James A Levine and Jennifer M Miller, published in May 2007 was conducted at the experimental office facility of the Mayo clinical research center in Minnesota, USA.

What kind of research was this?
This study was a Nonrandomized trial (quasi-experiment). In this study it was the comparison between the metabolic rates of different scenarios.

What did the research involve?
The data was produced from fifteen healthy, sedentary, obese individuals with a BMI of 30–35 kg/m2 currently working in a seated office setting


 * Subjects fasted for >6 hours with no exertional activity in that time.
 * No Caffeine for >6 hours, nor alcohol for >12 hours prior to the study.
 * All subjects were weighed on a calibrated standing scale, and height measured using a stadiometer.
 * Body composition was assed using a DXA scanner.

Then having their energy expenditure measured by a calibrated high precision indirect calorimeter for 20 minutes in multiple positions for comparisons such as
 * Office chair sitting.
 * Standing
 * Lying motionless
 * Walking energy expenditure at three speeds. 1,2,3 mph on the walk and work desk. Followed by a rest.

Finally the last assessment was while walking at a self-selected speed, the subjects were asked to type about the past day with energy expenditure measured between the 15 and 35-minute mark of the hour walked.

What were the basic results?
The results found significant positive correlations between weight and resting energy expenditure and also between fat free mass and resting energy expenditure. As the hypothesis proposed, energy expenditure increased significantly with walking in comparison to sitting. With each increase in MPH the energy expenditure also increased. Energy expenditure while seated was 72 ± 10 kcal/h whereas the energy expenditure whilst walking at a self selected speed of generally 1.1 mph ± 0.4 was over 2.5 times higher than seated at 191 ± 29 kcal/h.

How did the researchers interpret the results?
The researchers found the participants enjoyed using the vertical workstations, suggesting they could easily be implicated to real offices. Proving this, in 2009 the ‘Trekdesk’ treadmill desk entered the market as the first height adjustable desk that fit any existing treadmill. Based on the energy expenditure results Levine believed if the station was used to replace 2–3 hours each day of sitting and if other energy balances were constant a weight loss of 20–30 kg/year could occur.

What conclusions should be taken away from this research?
While the walk-and-work promotes long-term activity spanning at least an hour at a time, current workplace strategies in increasing physical activity have proven to be too short (e.g. Climb the stairs), Occupational health interventions should aim to reduce workplace and leisure-time sitting in sedentary office workers, which in contrast to the former options the walk-and-work desk achieves. The study demonstrates sedentary office behavior can be reduced and in theory could reverse obesity prevalence in an office setting; many other factors are dependent on this occurring such as individual energy intake, which wasn’t measured during the trials. Currently, people who are sedentary accumulate an energy excess of ~100kcal/day this can be attributed to long term weight gain. It's possible the Walk-and-work desk could easily reverse those effects.

What are the implications of this research?

 * Studies of each individual were short, and did not span the entire workday.
 * Only a few subjects, and 14 of 15 were women. Greater numbers would be unlikely to alter the found results.
 * The trial might have had better comparison results if there were control groups to compare data against.
 * In a realistic scenario would the workers had not had caffeine, alcohol or fasted in the allotted time?
 * The volunteers wrote about their past day rather than ‘worked’ would this result in less workplace efficiency?

Later studies in relation to Levine's results
Dinesh John's longitudinal study inspired by the findings of Levine & Miller did similar research, slow walking on a similar work station with the results showing declines in waist and hip circumferences and improving the lipid and metabolic profiles, but only marginal reductions in body weight. However, Levine was involved in a 12-month trial in 2013 and findings showed that obese subjects lost an average of 2.3+/-3.5 kg. The subjects daily sedentary time reduced from 1,020 ± 75 min/day to, at 6 months, 929 ± 84 min/day, and at 12 months, 978 ± 95 min/day. Suggesting the desks were not used for the amount of time originally suggested by Levine's original results.

In 2012 Rachel E. Funk studied the effectiveness of walk-and-work treadmills selected speeds and how they impacted on typing efficiency. Identifying the treadmill walking had a detrimental effect on typing at speeds of 1.3 and 3.2 Km/h but at 2.25 km/h (1.4MPH) produced the same efficiency as seated typing. Which is slightly faster than the 1.1MPH self selected speeds of Levine's trials, The subjects from Funk's observations were at a mean age of 23.2.