Inactivity to Obesity, and Vice Versa

Obesity in middle aged women may contribute to decreasing physical activity

(RxWiki News) There's a strong link between inactivity and the rising obesity epidemic in the United States. Now it seems that link may be a two-way relationship.

Obesity may be tied to decreases in physical activity among middle-aged women, according to a new study.

The findings are consistent with the increasing prevalence of obesity in adults and other trends in the US, according to researchers.

"Stay active, no matter your weight."

It has been well established that a lack of physical activity can increase weight and lead to obesity. But until now, it was unclear whether obesity could lead to physical inactivity.

A recent study, led by Jared M. Tucker, a former graduate student from Brigham Young University, investigated this relationship.

More than 250 women averaging about 42 years of age were included in the study. Researchers measured participants' body fat and how often they were engaged in physical activity.

To measure how fast and how often each person moved or gained speed, each of the participants wore an accelerometer for one week at the start of the study and 20 months later.

Just under half the women were obese. Obesity was defined as having more than 32 percent body fat.

Over the 20-month period, physical activity slowed down significantly among obese women compared to non-obese women, researchers found.

Specifically, activity decreased 8.1 percent for obese women over the course of the study. At the same time, physical activity decreased less than 1 percent for non-obese women.

With regards to the intensity of exercise, moderate and vigorous activity decreased by about half an hour per week among obese women. For non-obese, moderate and vigorous activity only decreased by about six minutes a week.

In total, participants covered about 2.7 million step counts each week.

"Obesity may increase barriers to physical activity through increased discomfort from osteoarthritis and functional limitations, as well as increased perceived exertion for a given activity," researchers wrote in their report.

"Additional research is needed to help elucidate these underlying mechanisms. Doing so will allow future physical activity promotion to target these barriers and potentially improve their success among obese individuals," they wrote.

Jim Crowell, head trainer at Integrated Fitness and dailyRx Contributing Expert, has worked with individuals who conquered their mental hurdles and physical fears with major success.

"I have seen many examples of people who, as they gained weight, decreased their activity levels. It is common," Crowell said. 

"In my opinion, I associate these changes to a few major ideas: emotional fear of working out looking like they do, lack of energy from all of the extra weight, lack of understanding of what workouts to do, and fear of failure," he said.

The authors noted that increases in obesity weren't necessarily the cause of increases in inactivity. In addition, the participants might not be representative of other populations.

The study was recently published online in Obesity, the journal of the Obesity Society. No conflicts of interest were reported.

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Review Date: 
April 3, 2013