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Background: Compared with structured/organized activities, unstructured, self-selected physical activity (PA) may be more appealing for children in particular obese (OB) children. We examined whether both healthy-weight (HW) and OB children would engage in moderate to vigorous intensity PA during an unstructured PA program and compared heart rate (HR) and rate of perceived exertion (RPE) between the children., Methods: Twenty-one children [9 OB (≥95th BMI percentile, 12 HW (5th - <85th), 8.6 ± 0.8 years; 9 males, 12 females] participated in before-school (7:30 AM to 8:15 AM) PA for 18 weeks, 3 consecutive days/week. Each child wore a Polar E600 HR monitor and was provided a vigorous, age-targeted heart rate (THR) of 70%., Results: Mean HR ≥ vigorous THR for all children in 65.3% of the sessions and exceeded moderate intensity in 100%. Over the 18-weeks, no significant difference was observed in the overall mean HR between the HW (171.4 ± 12.0) and OB (169.3 ± 13.0), however the OB reported significantly lower RPEs than the HW (16.9 ± 2.6 vs. 17.6 ± 1.5, respectively; P < .05)., Conclusions: Both the HW and OB children consistently sustained PA of moderate and vigorous intensity. The current study provides insight regarding the physiological capabilities and perceptual responses of HW and OB children participating in PA programs.

Childhood obesity is a significant, worldwide, public health problem. Coinciding with the increasing prevalence of obesity in youth, Type 2 diabetes has emerged as a critical health condition in this population. In the U.S. alone, approximately 215,000 U.S. youth under the age of 20 were diagnosed with diabetes, with the majority of 10-19 years old diagnosed with Type 2 diabetes. Additionally, the exact number of youth that may have Type 2 diabetes yet remain undiagnosed is unknown. Increasing physical activity to encourage weight loss among youth may reduce the incidence of Type 2 diabetes in youth; however, several recent studies reported positive associations between physical activity and components of Type 2 diabetes without weight loss in youth. These findings support previous studies in adults which observed physical activity-induced improvements in insulin dynamics without changes in body fat. The purpose of this review was to identify studies which examined the effect of physical activity without dietary intervention on markers of insulin resistance in overweight and obese youth. These studies provide strong evidence that physical activity alone, without dietary intervention, can have a positive, significant impact on insulin resistance risk and potentially prevent the development of type 2 diabetes in overweight and obese youth. The studies reviewed provide support for future interventions to shift the focus from reducing obesity to increasing physical activity for the prevention of type 2 diabetes in obese youth.

Objectives: 1) Report the feasibility of completing the 180-minute Frequently Sampled Intravenous Glucose Tolerance Test (FSIVGTT) in healthy weight, overweight and obese pre-pubertal children and, 2) describe the finalized FSIVGTT protocol after addendums were implemented to decrease the frequency of mild adverse events and improve test completion rates., Methods: Insulin sensitivity was determined by FSIVGTT., Results: FSIVGTT was attempted in a total of 22 study participants. Insulin sensitivity was successfully assessed in 15 study participants (8 males, 7 females, 10 Caucasian, 4 African American, 1 Pacific Islander, age range 7-9 years). Mean insulin sensitivity was 15.1+/-9.8 (mmicro/l)(-1) min(-1) range 4.4-43.2 (mmicro/l)(-1) min(-1). However, seven study participants experienced mild adverse events of hypoglycemia. Several addendums were made to the FSIVGTT protocol to ensure study participants' comfort and safety, and to decrease the frequency of mild adverse events and increase test completion rates., Conclusions: Addendums made to FSIVGTT protocol allowed successful completion of FSIVGTT in 15 (68%) of the 22 children. These results demonstrate that FSIVGTT is challenging, yet feasible in healthy lean and obese pre-pubertal children.