Reference Values of Aerobic Fitness in the Contemporary Paediatric Population

In most pediatric medical conditions, tremendous progress in pediatrics has significantly improved the overall prognosis and transferred the mortality from childhood to adulthood. Nevertheless, chronic diseases remain the leading cause of death and physical inactivity appears to be a major aggravating factor. Yet, a good physical activity has a positive impact on quality of life and prevents future health morbidities, such as obesity and cardiovascular disease. Therefore, after focusing on the survival of children with chronic diseases, more attention is being given to health-related quality of life and secondary prevention. In this context, the cardio-pulmonary exercise test (CPET), which is a non-invasive and dynamic examination, has become the gold standard to identify subjects with impaired physical capacity and to identify the causes of their limitations (muscular, cardiac, respiratory, behavioral, etc.). Moreover, CPET is the key examination to enroll patients in personalized physical rehabilitation programs (muscle deconditioning, respiratory limitation, etc.). Despite a growing interest in CPET and individualized rehabilitation programs for chronic diseases, the investigators still face the lack of reference values for pediatric CPET. In current practice, many CPET pediatric laboratories use the reference values of maximum oxygen uptake (VO2max) defined by Cooper et al. in 1984, from a cohort of 109 healthy children. However, their equations are linear and based on weight only. Non linear equations and the use of other anthropometric variables may be relevant in pediatrics. For instance, in the current era, normal CPET pediatric values should consider the prevalence of overweight and obesity in childhood general population (respectively 30% and 10% in Europa and 35% and 25% in North America), as well as in the population of children with chronic disease. In the past decade, our group has developed a research program on physical capacity in children, with a focus on pediatric CPET and physical rehabilitation, from a cohort of nearly 1000 exercise tests in children. The lack of reliable pediatric reference values for VO2max, and all CPET variables as well, has become an important issue. In this study, the investigators aim to define pediatric reference CPET values from a large cohort of 6 to 17 year-old children, using several anthropometric variables to define the most appropriate Z-scores equations (part 1). The investigators will also validate the Z-scores equations using an independent population (part 2).