Abstract

Background This article aimed to systematically review the contribution of physical education (PE) classes to improve cardiorespiratory fitness (CRF) in children and adolescents; and to define potentially relevant factors for promoting CRF in PE classes. Methods Studies were identified from searches in ERIC, PubMed, SPORTDiscus, and Web of Science databases. Primary source articles, relating PE classes and CRF, published up to July 2019 in peer-reviewed journals were eligible for inclusion. Specific inclusion criteria were: (a) having cross-sectional or longitudinal and observational or interventional study designs; (b) targeting school-aged children or adolescents; (c) measuring CRF, heart rate or CRF test results as an outcome; (d) having statistical analyses of the CRF, heart rate or CRF test results outcomes reported; (e) focusing on PE classes or PE interventions that did not extended time or frequency of the classes; and (f) published in English, French, Portuguese, or Spanish. Results A total of 24 studies met the inclusion criteria. Overall, 10 studies have found a neutral effect of PE classes in students' CRF, eight studies found that PE indeed contributed to the improvement of CRF and six studies revealed mixed findings, when PE classes where controlled for others variables (e.g. body mass index, intensity). Higher intensity PE classes consistently demonstrated contributions to improving students' CRF. Conclusion Review findings suggest that PE classes can contribute to the improvement of students' CRF. Intensity, age and weight status were identified as potentially relevant factors for promoting CRF in PE classes. To improve CRF, higher intensity classes should be provided.