La Fe participates in the validation of a model to assess cardiopulmonary fitness in children and adolescents

The study shows that this model, based on a statistical tool known as the Z-score, provides more accurate and consistent results than traditional equations used since the 1980s, particularly in children and adolescents with overweight.

The research included more than one thousand healthy participants under the age of 18 and used data from a Spanish population to validate a model developed from a previously published international reference population. Three hospitals in Spain participated: Hospital La Fe in València, Hospital Universitario Donostia and Hospital Universitario Virgen del Rocío in Seville.

Cardiopulmonary fitness is assessed through an exercise test that measures how the heart, lungs and muscles respond during physical activity. One of its main indicators is maximal oxygen uptake, which reflects the body's ability to use oxygen during intense physical exertion.

In pediatrics, these tests are used to investigate exercise-related symptoms, monitor children and adolescents with cardiac or respiratory diseases, and guide physical activity and rehabilitation programmes.

Until now, the interpretation of results has mainly relied on equations that take weight or height into account. However, these methods do not always adequately reflect the changes that occur during growth, particularly in children and adolescents who are underweight, overweight or have obesity.

The validated model uses the Z-score, a statistical system that allows each child's or adolescent's results to be compared with the expected values for individuals with similar characteristics.

This reduces the influence of body weight on the interpretation of results and provides a less biased assessment of cardiopulmonary fitness, particularly in children and adolescents with overweight.

Applications in Clinical Follow-up and Rehabilitation

The validation of this model may help identify children and adolescents with low aerobic capacity more accurately, a factor associated with cardiovascular and metabolic health.

It may also be useful in guiding the follow-up of pediatric patients with chronic diseases, adapting exercise intensity to their needs, and assessing their progress following rehabilitation programmes or lifestyle interventions.

"The aim is not simply to obtain a figure, but to better understand what that figure means for each child or adolescent," said Dr Esteban Peiró, pediatric cardiologist and researcher at Hospital La Fe and the Health Research Institute La Fe.

"This Z-score model has demonstrated significantly greater accuracy than traditional linear equations from the 1980s. Its robustness is particularly important for reliably determining fitness in children with overweight, a population in which older methods tended to fail," he added.

The study concludes that the Z-score model provides a more accurate and consistent interpretation of pediatric cardiopulmonary fitness than traditional methods. Its use could help improve clinical assessment, patient follow-up and the evaluation of interventions aimed at improving physical fitness.

The research is part of the European QUALIREHAB project, a hybrid cardiac rehabilitation programme designed to improve the lives of children and adolescents living with chronic diseases. The project is carried out by a consortium bringing together leading centres in France, Germany, the United States and Spain. It has received funding from the Spanish National Sports Council and the European "Innovate to Prevent" call (JTC-THCS 2024). The study is registered on ClinicalTrials.gov (NCT04876209).