IJCS | Volume 32, Nº4, July/August 2019

349 Table 5 - Comparison between cardiorespiratory fitness tables with the number of individuals classified as having higher, lower, or similar fitness Comparison Lower n (%) Similar n (%) Higher n (%) Total n Wilcoxon Kappa AEMA vs AHA 1,286 (21.41) 2,604 (43.29) 2,121 (35.30) 6,011 < 0.001 0.291 AEMA vs COOPER 458 (7.32) 2,354 (37.55) 3,457 (55.13) 6,269 < 0.001 0.220 AEMA vs UNIFESP 0 (0.00) 1,968 (36.04) 3492 (63.96) 5,460 < 0.001 0.201 AHA vs COOPER 782 (13.60) 2,426 (42.18) 2545 (44.23) 5,753 < 0.001 0.274 AHA vs UNIFESP 288 (5.84) 1,199 (24.26) 3457 (69.91) 4,944 < 0.001 0.112 COOPER vs UNIFESP 324 (6.23) 2,738 (52.62) 2,140 (41.14) 5,202 < 0.001 0.361 Almeida et al. Cardiorespiratory fitness classification Int J Cardiovasc Sci. 2019;32(4):343-354 Original Article populations or from small samples should be tested in Brazilian people, since the mere extrapolation of data may lead to serious errors. 26 In addition, different methods used for VO 2peak estimation (mostly by mostly by treadmill test rather than CPET), the criteria used for CRF classification, and different ages of the populations may have contributed to the discordant results of our study. In Cooper’s classification, 16 proposed with data from individuals aged older than 13 years, regardless of physical activity level, oxygen consumption was estimated by the maximal duration of the modified Balke protocol. This classification was based on small studies that reported a correlation between test duration and oxygen consumption of 0.92 for men 27 and 0.94 for women. 28 The UNIFESP classification 18 was based on physically inactive, apparently healthy individuals (311 men and 187 women) aged between 20 and 59 years, with adjustment of the curve VO 2peak vs. age and direct measurement of oxygen consumption by CPET. It is of note that, despite its wide use, there is no original publication in the literature demonstrating that the AHA classification table was actually developed by the AHA. After an exhaustive search in the literature, and even making contact with members of the Association, we did not find any original article published in indexed journals or any document issued by the AHA. All we know is that the supposed AHA classification for CRF was developed with individuals of both sexes, aged between 20 and 69 years. More recently, a nationwide classification systemwas published by Herdy and Caixeta. 19 The authors studied only individuals described as physically active, with no correlation with demographic data, which made it impossible to compare their data with ours. Also, generalization of results was limited due to the fact that the authors excluded physically active subjects as well as healthy obese individuals, since these characteristics (sedentary lifestyle and obesity) are present in a large proportion of the Brazilian population. TheAEMA table derived froma sample predominantly (84%of the sample) composedof residents of the northeast region of Brazil, with proportional representation of variables such as sex and physical activity level, comparable to the general population. Clear and strict criteria used in the methodology and the measurement of the VO 2peak by the CPET (individualized ramp protocol), make this classification system an attractive instrument, with high potential to be used in clinical practice. It is of note that not only the differences observed in the study group but also the method used in the study seem to explain the different results obtained in comparison with those of the other tables. 16-18 The AEMA table include children aged between 7 and 12 years old; this age range is not included in the other tables, and hence a direct comparison in this age group was not possible. It is worth pointing out that in this age group, there was a high percentage of physically inactive (62.5%), overweight children, and with a family income of three minimum wages (67.5%). Rodrigues et al., 29 evaluated 380 school children aged 10-14 years attending public schools. Mean VO 2peak in children aged between 10 and 12 years was 43 mL.kg -1 .min -1 (boys) and 38 mL.kg -1 . min -1 (girls); mean BMI was 17 for boys and 18 for girls. In our study, in children aged 10-12 years, mean VO 2peak was 37 and 29 mL.kg -1 .min -1 for boys and girls, respectively. Apossible explanation for such difference may be related