IJCS | Volume 32, Nº4, July/August 2019

332 Araújo et al. CLINIMEX aerobic fitness questionnaire Int J Cardiovasc Sci. 2019;32(4):331-342 Original Article Perhaps, in a clinical context, there is no other variable that outweighs aerobic fitness in terms of relevance to major adverse outcomes such as cardiovascular, cancer and all-cause mortality, 8 and each 1 MET increase in aerobic fitness is associated with long-term risk reduction of 10 to 15% chance of dying. 9,10 Even more interesting, a recent analysis of important cohorts in United States and Finland has shown that middle-aged or older men that improve their aerobic fitness over time tend to substantially decrease their mortality rate. 11-13 The gold standard for aerobic fitness determination is the measurement of maximum oxygen uptake (VO 2 max) during maximal cardiopulmonary exercise test (CPET), 7,14,15 by progressively increasing exercise intensity in an ergometer, most often a treadmill or a leg cycle ergometer, until volitional exhaustion, while collecting and analyzing expired gases. However, despite the existence of several institutional guidelines, 14,16 for a number of reasons, the use of CPET for quantifying aerobic fitness remains quite limited around the world and in Brazil. In this context, non-exercise alternatives to estimate aerobic fitness could be worth exploring. Moreover, even when CPET is available, estimating aerobic fitness would help to plan a more precise ramp protocol, that is, initial and incremental rate per minute in watts or speed/slope for a maximal CPET that will last around 10 minutes. 17 In a study with 63 subjects, 18 it was found that using measured VO 2 max as the gold standard, well-educated adults were reasonably well capable of classifying themselves as having much lower, lower, similar, higher or much higher aerobic fitness of what should be expected for their sex- and age-matched peers. In a classical study, researchers 19 have proposed the Veterans Specific Activity Questionnaire (VSAQ) to estimate aerobic fitness, obtaining good association - r = 0.79 - between VSAQ and measured VO 2 max. The VSAQ has been largely used 20-22 and it has been transculturally adapted to Brazil 23,24 with reasonable results. However, despite several merits, the VSAQ also has some important limitations: 1) it was primarily validated in a sample of middle-aged and old men; 2) the relatively long-time needed for the subject to read all the 21 lines in order to classify him(her)self; 3) the upper limited score - 13METs - that excludes many healthy exercisers and athletes; and 4) the unique one-MET interval across all scales, potentially losing discrimination for those placed in the lower range of aerobic fitness. Therefore, it seems an interesting proposal to develop a Brazilian questionnaire for estimating aerobic fitness that would be culturally adjusted to its population and that would circumvent the main limitations of VSAQ. The performance of CPET in a well-controlled setting, in men and women presenting a large age range and extremes of aerobic fitness, offered an outstanding and unique research opportunity to prospectively assess the validity of a new questionnaire, the CLINIMEX Aerobic Fitness Questionnaire (C-AFQ). The objectives of this study were: a) to propose the C-AFQ; b) to validate C-AFQ against the gold standard measured VO 2 max; c) to compare the physician’s statistical error of estimating aerobic fitness by C-AFQ; and d) to analyze the influence of age, sex, clinical conditions, regular use of ß-blockers and two non-aerobic fitness test scores on the error of estimate of aerobic fitness by C-AFQ. Methods Study sample Prospective data collection started in January 5 th 2016 and was planned to continue until data from a total of 1,000 subjects was obtained. As previously defined in the research design, subjects younger than 14 or athletes 25 or those not completing a true maximal cardiopulmonary exercise test (CPET) were not included in the study. 26,27 In addition, those with any missing or incomplete relevant data were also excluded. The final sample of 1,000 subjects was completed inMay 7 th 2019. The vast majority of subjects (98%) were white and pertaining to a high socioeconomic class. All subjects voluntarily went to our Clinic for the evaluation protocol. Before the evaluation, all subjects read and signed a specific informed consent formpreviously approved by the institutional committee on ethics in research. The final sample included 686 men (68.6%) aged 14 to 96 years (mean ± standard deviation: 55.2 ± 16.4 years). From the total of 1,000 subjects studied, 72.5% were evaluated for the first time in our Clinic, while the remaining 27.5% had been evaluated between two and 20 times. Regarding the subjects’ clinical conditions, 22% were considered healthy (no cardiorespiratory or major diseases reported), 23.3% had a diagnosis of coronary artery disease, including 12.2% with previous myocardial infarction, 15.2% that had been submitted to coronary angioplasty and 5.9% to coronary artery