Influence of Cardio-ventilatory Factors on Exercise Intolerance in Obese Adolescents: Effects of Exercise Training (VENTILOBE)

Influence of Cardio-ventilatory Factors on Exercise Intolerance in Obese Adolescents: Effects of Exercise Training

Influence of Cardio-ventilatory Factors on Exercise Intolerance in Obese Adolescents: Effects of Exercise Training

Worldwide, childhood and adolescent obesity has reached epidemic proportions despite major efforts to promote weight reduction. Pediatric obesity commonly presages adult obesity and is associated with the development of weight-related comorbid conditions and increased morbidity. Regular physical activity is an important modality of obesity management. Despite controversies, poor exercise tolerance has frequently been reported in youth obesity and the cause of this limited exercise tolerance remains unknown. Several factors accompanying obesity may interfere with exercise tolerance in obese populations. Respiratory factors, such as decreased thoracic compliance, increased airway resistance and breathing at low pulmonary volumes are associated with obesity and may impact exercise intolerance in this population. Moreover, even in people with otherwise normal lungs, the normal ventilatory responses to exercise can become constrained in obesity. A thorough understanding of the mechanisms underlying this exercise intolerance remains fundamental in order to favour long term adherence to exercise training. This is especially true in youth populations, in which the management of overweight and obesity must be undertaken as soon as possible, due to the early onset of cardiovascular risk factors. The main purpose of this study is to determine early-onset cardio-respiratory mortality factors in obese adolescents as well as their relation with exercise intolerance (i.e. dyspnea) when compared with age and gender-paired normal-weight volunteers.

Physiopathological trial. Expected total enrollment : 20 obese adolescents + 20 control subjects Tested treatment: Exercise training (4 hours per week). Treatment duration: 12 weeks

12-week supervised exercise-training (ET) program consisting of two 60-min and one 120-min exercise sessions per week which focus mainly on aerobic exercises (cycling, treadmill, rower). Initial aerobic exercise intensity is set at 60 % of HR peak and will reach 80 % at the end of the ET protocol.

12-week supervised exercise-training (ET) program consisting of two 60-min and one 120-min exercise sessions per week which focus mainly on aerobic exercises (cycling, treadmill, rower). Initial aerobic exercise intensity is set at 60 % of HR peak and will reach 80 % at the end of the ET protocol.

Exercise tolerance (Expiratory flow limitation and Operational Lung Volumes at rest and exercise, cardiorespiratory and subjective responses to incremental exercise)

Explore the potential existence of obstructive sleep apnea and its effects on cardiovascular adaptations during exercise.

Inclusion Criteria: Male and female obese adolescents (BMI > IOTF 30, 12-16 years old) Exclusion Criteria: Cardiovascular pathology Pathology interfering with physical activity (neurological pathology, severe respiratory illness i.e. asthma, renal failure) Diabetes (known or treated) Participation in another study Asthma (known and treated)