Assessment of the five-minute oxygen uptake efficiency slope in children with obesity

Purpose: Poor cardiorespiratory fitness is associated with increased all cause morbidity and mortality. In children with obesity, maximum oxygen uptake (VO) may not be achieved due to reduced motivation and peripheral fatigue. We aimed to identify a valid submaximal surrogate for VO in children with obesity. Method: Ninety-two children with obesity (7-16 years) completed a maximal exercise treadmill test and entered a three-month exercise and/or nutrition intervention after which the exercise test was repeated (n = 63). Participants were required to reach VO to be included in this analysis (n = 32 at baseline and n = 13 at both time-points). The oxygen uptake efficiency slope (OUES) was determined as the slope of the line when VO (L/min) was plotted against logV? E. Associations between the maximal OUES, submaximal OUES (at 3, 4, 5 and 6 min of the exercise test) and VO were calculated. Results: In the cross-sectional analysis, V?O2max (L/min) was strongly correlated with 5-min OUES independent of Tanner puberty stage and sex (R = .80, p < .001). Longitudinal changes in VO were closely reflected by changes in 5-min OUES independent of change in percent body fat (R = .63, p < .05). Conclusion: The 5-min OUES is a viable alternative to VO when assessing children with obesity

Effect of high intensity interval training on cardiac function in children with obesity: a randomised controlled trial

High intensity interval training (HIIT) confers superior cardiovascular health benefits to moderate intensity continuous training (MICT) in adults and may be efficacious for improving diminished cardiac function in obese children. The aim of this study was to compare the effects of HIIT, MICT and nutrition advice interventions on resting left ventricular (LV) peak systolic tissue velocity (S') in obese children.Ninety-nine obese children were randomised into one of three 12-week interventions, 1) HIIT [n = 33, 4 × 4 min bouts at 85-95% maximum heart rate (HR), 3 times/week] and nutrition advice, 2) MICT [n = 32, 44 min at 60-70% HR, 3 times/week] and nutrition advice, and 3) nutrition advice only (nutrition) [n = 34].Twelve weeks of HIIT and MICT were equally efficacious, but superior to nutrition, for normalising resting LV S' in children with obesity (estimated mean difference 1.0 cm/s, 95% confidence interval 0.5 to 1.6 cm/s, P

Effects of exercise intensity and nutrition advice on myocardial function in obese children and adolescents: a multicentre randomised controlled trial study protocol.

Introduction The prevalence of paediatric obesity is increasing, and with it, lifestyle-related diseases in children and adolescents. High-intensity interval training (HIIT) has recently been explored as an alternate to traditional moderate-intensity continuous training (MICT) in adults with chronic disease and has been shown to induce a rapid reversal of subclinical disease markers in obese children and adolescents. The primary aim of this study is to compare the effects of HIIT with MICT on myocardial function in obese children and adolescents. Methods and analysis Multicentre randomised controlled trial of 100 obese children and adolescents in the cities of Trondheim (Norway) and Brisbane (Australia). The trial will examine the efficacy of HIIT to improve cardiometabolic outcomes in obese children and adolescents. Participants will be randomised to (1) HIIT and nutrition advice, (2) MICT and nutrition advice or (3) nutrition advice. Participants will partake in supervised exercise training and/or nutrition sessions for 3 months. Measurements for study end points will occur at baseline, 3 months (postintervention) and 12 months (follow-up). The primary end point is myocardial function (peak systolic tissue velocity). Secondary end points include vascular function (flow-mediated dilation assessment), quantity of visceral and subcutaneous adipose tissue, myocardial structure and function, body composition, cardiorespiratory fitness, autonomic function, blood biochemistry, physical activity and nutrition. Lean, healthy children and adolescents will complete measurements for all study end points at one time point for comparative cross-sectional analyses. Ethics and dissemination This randomised controlled trial will generate substantial information regarding the effects of exercise intensity on paediatric obesity, specifically the cardiometabolic health of this at-risk population. It is expected that communication of results will allow for the development of more effective evidence-based exercise prescription guidelines in this population while investigating the benefits of HIIT on subclinical markers of disease

Effect of high-intensity interval training on fitness, fat mass and cardiometabolic biomarkers in children with obesity: a randomised controlled trial

Background: Paediatric obesity significantly increases the risk of developing cardiometabolic diseases across the lifespan. Increasing cardiorespiratory fitness (CRF) could mitigate this risk. High-intensity interval training (HIIT) improves CRF in clinical adult populations but the evidence in paediatric obesity is inconsistent. Objectives: The objectives of this study were to determine the efficacy of a 12-week, HIIT intervention for increasing CRF and reducing adiposity in children with obesity. Methods: Children with obesity (n = 99, 7–16 years old) were randomised into a 12-week intervention as follows: (1) HIIT [n = 33, 4 × 4-min bouts at 85–95% maximum heart rate (HR), interspersed with 3 min of active recovery at 50–70% HR, 3 times/week] and nutrition advice; (2) moderate-intensity continuous training (MICT) [n = 32, 44 min at 60–70% HR, 3 times/week] and nutrition advice; and (3) nutrition advice only (nutrition) [n = 34]. CRF was quantified through a maximal exercise test ((Formula presented.)) while adiposity was assessed using magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry (DXA) and air-displacement plethysmography. Results: HIIT stimulated significant increases in relative (Formula presented.) compared with MICT (+3.6 mL/kg/min, 95% CI 1.1–6.0, P = 0.004) and the nutrition intervention (+5.4 mL/kg/min, 95% CI 2.9–7.9, P = 0.001). However, the intervention had no significant effect on visceral and subcutaneous adipose tissue, whole body composition or cardiometabolic biomarkers (P > 0.05). Conclusion: A 12-week, HIIT intervention was highly effective in increasing cardiorespiratory fitness when compared with MICT and nutrition interventions. While there were no concomitant reductions in adiposity or blood biomarkers, the cardiometabolic health benefit conferred through increased CRF should be noted. Clinical trials registration number: Clinicaltrials.gov; NCT01991106