Healthy Eating, Aerobic and Resistance Training in Youth (HEARTY): study rationale, design and methods.
ABSTRACT The objective of the Healthy Eating Aerobic and Resistance Training in Youth (HEARTY) trial (ClinicalTrials.Gov # NCT00195858) was to examine the effects of resistance training, with and without aerobic training, on percent body fat in sedentary, post-pubertal overweight or obese adolescents aged 14-18 years. This paper describes the HEARTY study rationale, design and methods.
After a 4-week supervised low-intensity exercise run-in period, 304 overweight or obese adolescents with a body mass index≥85th percentile for age and sex were randomized to 4 groups for 22 weeks (5 months): diet+aerobic exercise, diet+resistance exercise, diet+combined aerobic and resistance exercise, or a diet only waiting-list control. All participants received dietary counseling designed to promote healthy eating with a maximum daily energy deficit of -250 kcal.
The primary outcome is percent body fat measured by Magnetic Resonance Imaging. Secondary outcomes include changes in anthropometry, regional body composition, resting energy expenditure, cardiorespiratory fitness, musculoskeletal fitness, cardiometabolic risk markers, and psychological health.
To our knowledge, HEARTY is the largest clinical trial examining effects of aerobic training, resistance training, and combined aerobic and resistance training on changes in adiposity and cardiometabolic risk markers in overweight and obese adolescents. The findings will have important clinical implications regarding the role that resistance training should play in the management of adolescent obesity and its co-morbidities.
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ABSTRACT: Background Sedentary behavior has been associated with deleterious cardiometabolic health indicators in adults, but very little research has examined this relationship in youth. Purpose To examine the association between the duration and type of sedentary screen behavior with diabetes risk factors (fasting glucose, insulin, homeostasis model-insulin resistance [HOMA-IR], 2-hour postload glucose, hemoglobin A1c) in a sample of overweight and obese adolescents. Methods A cross-sectional study of 307 overweight or obese adolescents aged 14–18 years (90 boys, 217 girls) assessed at baseline of a lifestyle intervention for weight control conducted from 2005 to 2010. Sedentary screen behaviors, defined as hours per day spent watching TV, playing seated video games, recreational computer use, and total screen time were measured by self-report. Data were analyzed using linear regression analyses in 2012. Results TV viewing was the only type of sedentary screen behavior associated with elevated diabetes risk factors before and after adjustment for confounders. Specifically, TV viewing remained positively associated with fasting insulin (adjusted r=0.11, β=0.10, p=0.048) and HOMA-IR (adjusted r=0.11, β=0.10, p=0.05) after adjustment for age, gender, waist-to-hip ratio, caloric intake, percentage of intake in carbohydrates, physical activity duration, and physical activity intensity. Conclusions TV watching may be independently associated with an increase in diabetes risk factors in a high-risk sample of overweight and obese adolescents. These findings provide support for interventions designed to reduce time spent watching TV as a possible means to attenuating diabetes risk factors in this high-risk population. Trial registration This study is registered at clinicaltrials.govNCT00195858.American Journal of Preventive Medicine 04/2013; 44(4):S364–S370. DOI:10.1016/j.amepre.2012.11.040 · 4.28 Impact Factor
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ABSTRACT: Little evidence exists on which exercise modality is optimal for obese adolescents.JAMA Pediatrics 09/2014; 168(11). DOI:10.1001/jamapediatrics.2014.1392 · 4.25 Impact Factor