Tremendous progress in paediatrics has significantly improved the overall prognosis of chronic diseases and transferred the mortality from childhood to adulthood in an era where sedentary lifestyle, obesity and associated cardiovascular risk factors are rapidly increasing. The promotion of regular exercise is of utmost priority in the management of these patients. The cardiopulmonary exercise test (CPET) gives important prognostic information on functional capacity, haemodynamic response and can facilitate a safe decision-making process when prescribing exercise programs and sport participation for these children. Despite a growing interest in CPET and individualized rehabilitation programs for chronic diseases, we still face the lack of reference values for paediatric CPET and even more for “extreme” patients (especially in terms of weight). The main aim of this study is to define references values VO2_max and establish Z-scores in the paediatric population including extreme weights.

This cross-sectional study was carried out between November 2010 and November 2020 in two tertiary care paediatric cardiology reference centres and included children referred for a non-severe functional symptom linked to exercise (murmur, palpitation or dyspnoea) or for a medical sports certificate. These children had a completely normal check-up, including physical examination, ECG, echocardiography and spirometry.

In total, 909 children were included, 213 were overweight/obese and 107 were underweight. For both sexes, the best model was logarithmic with the combination of height and BMI. The equations are cited in the Fig. 1.

For the first time, we have paediatric reference values giving VO2_max Z-score that can be used for extreme weights. From this same cohort, we will soon publish the Z-score of the other CPET parameters and thus facilitate the interpretation of this paediatric examination and facilitate its use.