Globe & Mail: Prolonged bouts of sitting increase cancer riskNovember 9, 2011
New Scientist: Computer user suffers "eThrombosis"November 16, 2011
SBRN is pleased to host weekly summaries of peer-reviewed research in the area of sedentary behaviour, written by graduate students and young investigators working in a range of disciplines. Information on the author of today’s article can be found at the bottom of this post. If you are interested in writing a summary of an article that you found interesting, please contact us here.
It should come as no surprise that the office is a primary setting for the accumulation of sedentary time in adults. Recent research has even indicated that sedentary occupations are associated with negative health consequences such as heart disease and type 2 diabetes. To make matters worse, we are currently in the midst of a disturbing trend in occupational energy expenditure. Data from the last 50 years has indicated that occupational energy expenditure has fallen by approximately 140 calories for men and 120 calories for women. While this may not seem like a lot, it does account for a a significant amount of weight gain over the last five decades. In order to combat sedentary time in the workplace many individuals have begun modify their work environment by installing standing or treadmill-based desks. Gilson et al. sought to examine the efficacy and utility of standing “hot desks” for sedentary office workers.
What did they do?
The authors recruited 11 participants who worked in an office with an open floor plan. They were each given a SenseWear activity monitoring device to wear during waking hours for two weeks. During the first week the participants maintained their normal office behavior. Before the second week of data collection the authors installed four height adjustable desks. Each desk was equipped so that any employee could accomplish their normal tasks while at the desk. The participants were given information about reducing sedentary time and encouraged to use the desks. Participants recorded their desk usage (frequency, duration, sitting vs. standing) via log books.
What did they find?
Although the desk were adjustable, during the intervention period the desk were only used in standing positions. On average, participants used the desks for one hour per day. Mean usage was highly variable with a minimum of no use and a maximum of 9.5 hours of use over the 5 day intervention period. Data gathered from the SenseWear accelerometer indicated that there was no significant changes in sedentary, light, or moderate intensity activity.
What is the take home message?
To date, this is the first study to examine the effects of using standing desks in a free-living office environment. It appears that providing office employees with standing workstations will increase time spent standing and working. Although this is worthwhile result, the change in behavior is not reflected in objective monitored sedentary time. There are many possible explanations, but this speaks to the issue of using objective monitors, primarily accelerometers, to measure sedentary behaviors. Accelerometers work by measuring ground reaction force in different planes. If there is no movement, for example when standing still, the data may be misinterpreted as sedentary time. Future research should employ more sophisticated sensors such as the ActivPal that can differentiate between sitting and standing.
Reference: Nichols D. Gilson, Alessandro Suppini, Gemma C. Ryde, Helen E. Brown, Wendy J. Brown, Does the use of standing ‘hot’ desks change sedentary work time in an open plan office?, Preventive Medicine, In Press.
About the author: Ernesto Ramirez is currently a doctoral student in the Joint Doctoral Program (Health Behavior) at San Diego State University and University of California, San Diego. He is currently working at the Center for Wireless and Population Health Systems (CWPHS). He focuses on how to use existing and new technologies to better measure/understand behavioral patterns and then harnesses technology solutions to create effective interventions for individuals. He is interested in building and using systems that will take advantage of sensing, mobile, and social network technologies to better the health of individuals and populations.