In the Journals Plus

Brief walks improve glucose metabolism in children with overweight, obesity

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August 16, 2018

Among children with overweight and obesity, brief periods of moderate-intensity exercise yield improvements in glucose metabolism without substantially increasing energy intake, according to research published in Diabetes Care.

“On average, children remain sedentary during nonsleep periods for at least 6 hours per day,” Miranda M. Broadney, MD, MPH, of the division of intramural research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, and colleagues wrote in the study background. “Emerging evidence in adults and children suggests that extended time spent in sedentary behaviors is directly linked to poor metabolic outcomes including abnormalities in glucose homeostasis. Preliminary studies in adults and in children with healthy weight have demonstrated short-term improvements in glucose metabolism through interventions that interrupt sedentary behavior.”

In a randomized, crossover study, researchers evaluated data from 35 children aged 7 to 11 years who were classified as overweight or obese (BMI 85th percentile) based on CDC growth charts, had fasting plasma glucose less than 100 mg/dL and were in overall good health.

A screening visit was conducted to assess children for study eligibility, and participants returned on two separate dates to complete each portion of the experiment: uninterrupted sitting for 3 hours and sitting with short bouts of treadmill walking for 3 minutes every 30 minutes for 3 hours, in random order. Test visits were spaced 7 to 30 days apart to avoid potential carryover effects.

Children completed two 3-hour oral glucose tolerance tests on different days under the two study conditions to assess insulin, C-peptide and glucose levels. Before the study visit, participants wore a wrist accelerometer for 7 to 10 days preceding each visit to assess sleep habits and patterns of activity. At the end of each OGTT session, a more than 9,500-kcal standardized buffet-style test meal was provided. Primary outcomes were differences in OGTT-measured hormones and in buffet meal consumption based on the study scenario preceding it.

At screening, all participants had normal fasting glucose; 53% of participants had obesity, and 47% had overweight.

During the 3-hour OGTT, insulin secretion was lower for children after the sit/walk activity vs. the sitting activity (P = .007). Additionally, lower levels of C-peptide were observed in children after completing the sit/walk activity vs. the sitting-only activity (P = .03), according to researchers.

During the OGTT, mean insulin levels were lower at 60, 90, 150 and 180 minutes (P < .01 for all) after the sit/walk activity vs. the sitting-only activity, according to researchers.

After the sit/walk activity, mean insulin area under the curve was 21% lower vs. levels measured after the sitting-only activity (P < .001).

The two conditions did not yield between-group differences in total consumption during buffet meal intake (mean, 1,262 kcal vs. 1,260 kcal) or macronutrient content of the meal (P > .38).

The researchers noted that future studies should explore longer-term benefits of this type of intervention in children with overweight and obesity.

“Interrupting sedentary behavior in children with overweight and obesity improved their glucose metabolism acutely,” the researchers wrote. “If this intervention provides sustained improvement in glucose metabolism, given the logistic feasibility and child acceptance experienced in this study, widespread implementation into school or after-school care centers could provide notable improvement in glucose homeostasis in the community and potentially slow the onset of type 2 diabetes in youth.” – by Jennifer Byrne

Disclosures: The authors report no relevant financial disclosures.

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