Reference Standards for Cardiorespiratory Fitness in Brazil: A POOLED ANALYSIS AND OVERVIEW OF HETEROGENEITY IN NATIONAL AND INTERNATIONAL STUDIES.

ABSTRACT

PURPOSE: This study aimed to propose reference standards for cardiorespiratory fitness (CRF) for Brazil from a pooled analysis and to compare peak oxygen uptake (V˙ o2peak ) in Brazilian, United States (US), and Norwegian samples, exploring possible national and international differences. METHODS: Reference values for treadmill V˙ o2peak in three different Brazilian regions were assessed from previous publications. We analyzed available samples to assess possible differences, generate weighted average data for Brazil, and compared them with US and Norwegian data. RESULTS: Brazilian reference values had a lower V˙ o2peak value for the Northeast region and a higher V˙ o2peak value for the Southeast region for all sex and age groups. International comparisons with the Brazilian pooled data (n = 26661) revealed higher values for the Norwegian sample (n = 3810) and lower values for the US sample (n = 16278). The observed heterogeneity in CRF is possibly related to differences in anthropometric (weight, height) and socioeconomic factors, which differed among the samples. Also, Brazilian data showed a curvilinear V˙ o2peak age reduction trend rather than the linear characteristic commonly utilized, and the regression curves were different from those for US and Norwegian data. CONCLUSION: This study provides new CRF reference standards for Brazil. After pooling data from three Brazilian regions, a comparison revealed notable differences between regions, evidencing a negative gradient from Southern to Northern regions. Similarly, the international comparisons between Brazil, US, and Norway data revealed CRF heterogeneity, with differences in the V˙ o2peak values and in the age relationship patterns. These findings reinforce the importance of using national- or regional-specific V˙ o2peak reference values, ensuring proper CRF evaluation.