In the Journals

Sedentary behavior linked to poor CV health in severe obesity

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January 14, 2016

In adults with severe obesity, poor cardiovascular health and diabetes is linked to sedentary behavior, regardless of how much exercise they perform, according to recent findings.

“Adults with severe obesity often have difficulty following national guidelines to participate in at least 30 minutes per day of moderate- to vigorous-intensity physical activity for health benefits,” Wendy C. King, PhD, associate professor in the department of epidemiology at the University of Pittsburgh, Graduate School of Public Health, said in a press release. “Our findings suggest that replacing sedentary behavior, like watching television or sitting at the computer, with low-intensity physical activities, such as light housework or going for a casual stroll, may improve cardiometabolic health in this population.”

Wendy C. King

Wendy C. King

King and colleagues evaluated 927 adults with severe obesity (median age, 45 years; median BMI, 46 kg/m2) from the LABS-2 study, an observational study of patients undergoing weight-loss surgery, to determine if sedentary behavior is associated with cardiometabolic health. Prior to surgery, participants’ activity was measured using monitors that tracked the number of steps taken each minute for a 1-week period.

Three definitions of sedentary time were employed, which varied by the required minimum bout duration with no walking. When bouts as short as 1 minute were considered sedentary time, researchers found that median sedentary time was 9.3 hours per day. With minimum bout durations of 10 minutes and 30 minutes to establish sedentary time, the median values were 6.5 hours per day and 3.2 hours per day, respectively. Two-thirds of participants did not engage in any moderate- to vigorous-intensity physical activity.

Sedentary time defined as 10 minutes or more without walking led to stronger relationships between sedentary behavior and cardiometabolic health.

“This is important because accurate assessment of sedentary behavior is crucial to being able to evaluate if and how this behavior is related to health outcomes,” King said in the release. “If our estimate of sedentary behavior is poor, we may not detect true associations.”

After controlling for moderate- to vigorous-intensity physical activity, BMI and other potential confounders more sedentary time in at least 10 minute bouts was associated with greater odds of metabolic syndrome, elevated BP, diabetes and larger waist circumference.

Specifically, every hour per day of sedentary time was linked to 12% greater odds of metabolic syndrome (OR = 1.12; 95% CI, 1.01-1.24) and 15% greater odds of diabetes (OR = 1.15; 95% CI, 1.05-1.26).

“Per national physical activity guidelines, clinicians should continue to encourage patients with obesity to participate in moderate-to-vigorous intensity physical activity for at least 150 minutes/week to improve their cardiovascular and metabolic health,” King told Endocrine Today. “Per the guidelines, they should also stress that, ‘some physical activity is better than none.’ Given the cross-sectional nature of our study, we cannot establish causality. However, our findings suggest that replacing some sedentary behaviors, like watching TV, with low-intensity physical activities may also improve the cardiovascular and metabolic health of adults with severe obesity. Discussing the concept of breaking up periods of sedentary behavior with ‘activity breaks’ versus ‘exercise sessions’ may be helpful.” – by Amber Cox

For more information:

Wendy C. King, PhD, can be reached at kingw@edc.pitt.edu.

Disclosure: King reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.