CASH- Children Active to Stay Healthy (CASH)

Effects of High Intensity Interval Exercise on Inflammation and Endothelial Function in Children & Adolescents With Obesity

The purpose of this study is to examine the effects of high intensity interval exercise (HIIE) on inflammation and endothelial dysfunction found in children with obesity. Our working hypothesis is that, compared with obese children prescribed moderate exercise, obese children prescribed HIIE will demonstrate greater improvements in endothelial function and inflammatory markers following a 6-week exercise intervention.

Obesity, even in children, is generally accompanied by a state of chronic inflammation. To combat childhood obesity, clinicians and scientists recommend lifestyle interventions that include increased physical activity and exercise in an attempt to promote weight loss and, consequently, decrease comorbidities associated with excess adiposity. More importantly, it appears that the influence of regular exercise may offer children with obesity a multitude of health benefits, independent of weight loss. However, the intensity of exercise required to elicit significant health benefits is still unclear. Therefore, the aim of the present project is to study the influence of high intensity interval exercise (HIIE) on the existing inflammatory state found in obesity. Specifically, the proposed project will examine endothelial function and markers of inflammation, such as TNFa, IL-6, hsCRP, and adiponectin, in children with obesity before and after an exercise intervention. The data will then be used to determine if changes in these values differ in magnitude based on the intensity of exercise. Children with obesity will be randomized into either moderate exercise or HIIE groups, and attend sessions 3 times per week for 6 weeks. The moderate group will cycle continuously for 30 minutes at 65%-70% of maximal heart rate and the HIIE group will perform ten, 2-minute bouts at 90%-95% of maximal heart rate. Outcome measures of body composition, aerobic capacity, blood lipids, glucose metabolism, endothelial function, and inflammation will be measured pre- and post-intervention. Results may help in establishing exercise protocols not only for children with obesity, but also other inflammatory diseases such as diabetes, cancer, and arthritis.

The subject will participate in a 6-week exercise intervention, 3 days per week on a cycle ergometer. The moderate exercise group will begin with a five-minute warm-up, cycling at 50-55% of the subject's maximal heart rate as determined by the initial fitness assessment. Following the warm-up, the moderate group will cycle for 30 minutes at 65-70% of maximal heart rate. The subject will then complete a 5-minute cool-down at 50-55% of maximal heart rate. Heart rate will be measured via individual heart rate monitors.

The subject will participate in a 6-week exercise intervention, 3 days per week on a cycle ergometer. The subjects in the HIIE group will begin with a five-minute warm-up at 50-55% of the subject's maximal heart rate as determined by the initial fitness assessment. Following the warm-up, the HIIE group will perform 10, two-minute exercise bouts at 90-95% of maximal heart rate, with one minute of active recovery at 55% of maximal heart rate between each interval for a total of 30 minutes. They will complete the test with a 5-minute cool-down at 50-55% of maximal heart rate. Heart rate will be measured via individual heart rate monitors.

Inflammation and endothelial function measured via forearm vascular resistance (FVR) and blood markers including tumor necrosis factor alpha (TNF-a), interleukin-6 (IL-6), adiponectin, high sensitivity C-reactive protein (hsCRP), and endothelin 1.

The primary outcomes are the percent change in FVR and in inflammatory markers (hsCRP, IL-6, TNF-α, and adiponectin) from pre- to post-intervention in both groups.

Percent difference in inflammation and endothelial function between moderate and high intensity interval exercise (HIIE) groups.

Inclusion Criteria: 13-17 years old obesity (defined as as BMI≥ 95th percentile for age and sex as defined by the Centers for Disease Control Exclusion Criteria: active participation in ≥30 minutes of vigorous exercise more than 2 days per week participation in an organized combined diet/exercise weight loss intervention acute inflammatory disease or febrile illness recent trauma or injury asthma requiring steroid use or that has resulted in hospitalization within 3 months prior to enrollment chronic disease known to affect inflammation (e.g. lupus) any renal, heart, or liver disease

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