Obesity Does Slow People Down, Study Confirms
By Alan Mozes
The investigating team acknowledged that their observation so clearly aligns with conventional wisdom that it would be hard to describe it as “rocket science.” But they say theirs is the first study to rigorously establish what most scientists have long presumed to be the case: that obesity does indeed have a negative impact on an individual’s activity habits.
“An abundance of research has focused on factors that increase [the risk for] obesity, due to the many chronic diseases and conditions associated with it,” said study lead author Jared Tucker, currently a senior epidemiologist at the Helen DeVos Children’s Hospital in Grand Rapids, Mich. “And rightly so.”
“However, physical inactivity is also independently associated with many of the same chronic diseases, including cardiovascular disease and type 2 diabetes,” Tucker added. “But we don’t often think about factors that influence activity levels.”
Tucker was a graduate student when the research, reported online recently in the journal Obesity, was conducted.
“Our study suggests that obesity likely increases the risk of reducing physical activity levels in women,” Tucker said. “Therefore, it appears that physical inactivity and obesity may be involved in a feedback loop, in which lower levels of activity lead to weight gain, which then leads to lower levels of activity.”
To explore how obesity could depress activity levels among women, the authors focused on more than 250 middle-aged women living in the Mountain West region of the United States. Roughly half the participants were diagnosed as obese.
Rather than ask the women to self-report their activity routines — a study method that can undermine reliability — the team attached belt-strapped accelerometers to all the study participants. The small device measures movement of various accelerations and intensities. For a week, all the women were told to wear the straps throughout their day, except when exposed to water, such as while showering.
On average, the women wore the straps for nearly 14 hours out of the 15-hour daytime period (defined as 7 a.m. to 10 p.m.). This allowed the team to assess total time spent engaged in daily light, moderate or vigorous physical activity.
Body composition assessments were conducted just before the accelerometer monitoring began and again 20 months later. In turn, after the 20-month re-assessment, the women were again asked to wear the accelerometers for another week of activity monitoring.
The result: Among the obese participants, physical activity was found to drop by 8 percent overall over the course of the 20-month study period. This was equivalent to a loss of 28 active minutes per week, the researchers said.