Montclair State Professor Co-authors Study Linking Obesity and Workplace Physical Activity

June 9, 2011—A new study has found that the decrease in workplace physical activity over the past fifty years is a significant contributor to the obesity epidemic. According to Montclair State University mathematics professor Diana Thomas, PhD, one of the study’s co-authors, “Our findings indicate that the weight increases for men and women over the past 30 years cannot solely be attributed to increased caloric intake.”

The study, “Trends Over 5 Decades in U.S. Occupation-Related Physical Activity and their Associations with Obesity,” was published May 25 by the Public Library of Science (PLoS), in their peer-reviewed journal of science and medicine, PLoS ONE. 
Researchers from the Pennington Biomedical Research Center, Montclair State University, and the Arnold School of Public Health at the University of South Carolina examined the trends in occupational physical activities over the past five decades to concurrent changes in body weight in men and women in the United States. In the 1960s, more than one half of jobs included moderate physical activity in contrast to today's less than 20 percent, according to the new study.

“Yesterday’s jobs have been replaced by sitting or sedentary activity. In the last fifty years, we estimate that daily occupation-related energy expenditure has decreased by more than 100 calories per day, and this reduction accounts for a significant portion of the increase in mean U.S. body weights for women and men,” said lead author Pennington Biomedical scientist Timothy Church, MD, MPH, PhD.

“The causes of the obesity epidemic are a hotly debated issue, particularly in regard to the relative importance of diet and physical activity,” continued Church. “Our data provides further support to the importance of including both diet and physical activity in discussions related to be both the causes and potential solutions of the on-going obesity epidemic.”

In 2008, federal physical activity recommendations were released suggesting 150 minutes per week of moderate intensity or 75 minutes of vigorous intensity physical activity per week. However, only 1 in 20 Americans are meeting these guidelines. If men and women were meeting these recommendations, this would make up for the decreased activity levels in the labor work force.

In the study, the authors chose to focus on occupation activity as it represents the largest segment of waking hours for adults. Over the past 40 years, the workforce has also changed dramatically, with more women working today. Since 1970, the percentage of women in the workforce has risen from 43 percent in 1970 to 60 percent in 2007.

“As jobs have become more sedentary over the past 50 years, this study supports increasing physical activity during leisure time as well as encouraging additional movement in the workplace as vitally important both personally and as a public health initiative,” said Thomas.

The study’s authors include Timothy Church, MD, MPH, PhD, Catrine Tudor-Locke, PhD, Peter T. Katzmarzyk, PhD, Conrad P. Earnest, PhD, Ruben Rodarte, MS, Corby K. Martin, PhD, and Claude Bouchard, PhD, from the Pennington Biomedical Research Center; Diana M. Thomas, PhD, of Montclair State University; and Steven N. Blair, PED, of the University of South Carolina.

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