IJCS | Volume 32, Nº4, July/August 2019

340 Araújo et al. CLINIMEX aerobic fitness questionnaire Int J Cardiovasc Sci. 2019;32(4):331-342 Original Article The tool most often used in the literature to perform non-exercise estimate of aerobic fitness is the VSAQ. 19-21,23 Notwithstanding, as briefly mentioned in our introduction, it has several shortcomings or limitations and, as recently confirmed, its association with measured (CPET) VO 2 max is only moderate. 22 For instance, there are several differences between C-AFQ and VASQ that may help to explain why our C-AFQ data presented better association between estimated and measured aerobic fitness than the original VSAQ data. The first major difference is the range of exercise intensities covered in both questionnaires, with the 0.5 MET interval scale adopted in the lower range of the C-AFQ as compared to 1-MET interval across all VSAQ scales and the extension of scale to > 20METs in C-AFQ as compared with the 13-METmaximal limit in the original VSAQ, allowing both severely unfit and fitter subjects to be better quantified and discriminated by the C-AFQ. The secondmajor difference resides in the two-step approach used in C-AFQ versus the single-step approach in VSAQ. Interestingly, although apparently a two-step versus a single-step approach and the list of 63 activities in step 2 versus only 21 activities in the VSAQ would seem to be much more complicated, in practical terms, this was not true. Applying the step 1 of C-AFQ allowed a very simple and straightforward answer. Indeed, the vast majority of the subjects would be answering zones 3 to 6 and, according to sex, age and clinical conditions, an even more limited range could be initially asked by the interviewer. For example, in 50-year-old apparently healthymen, the interviewer could start C-AFQby asking if they are able to “run, slowly, at least 1 kmor 10 minutes without stopping or walking” (zone 5). If a negative response is given, the interviewed would downgrade to the question in zone 4 – are you able to “run, slowly, one block or 100 meters?,” otherwise, in case of a positive response to the first question, the interviewer would upgrade to zone 6 and the questionwould be if theywere able to “run, continuously, for up to 40 minutes” and the questioning would continue until the “best block or zone number” in step 1 is identified and then following to step 2. Having defined the proper block number in the step 2 of C-AFQ, five and twelve activities are listed according to exercise intensities estimated in METs. In this sense, C-AFQ is likely to be easier and faster to apply while still being more precise and more discriminative than VSAQ in identifying the subject’s maximal tolerable exercise and in estimating aerobic fitness (please see a demonstration video in supplemental materials).* Interestingly, the deltaMETs were quite similar among the four physicians that collaboratedwith C-AFQdata for this study. This suggests that adequately trained (after mastering the application C-AFQ instructions) health professionals would be able to successfully use C-AFQ in their practice to estimate aerobic fitness. Finally, several other associations, at varying degrees, were found. For the major study variable —delta METs between estimated (C-AFQ) and measured (CPET) VO 2 max — no clinically relevant influence was found regarding age, sex, height, weight, waist girth, body mass index, major clinical conditions, regular use of ß-blockers, type of CPET’s ergometer, SRT scores and maximal muscle power related to body weight. A small association was found between delta METs and relative measured METs expressed as % sex- and age-predicted METs, indicating a small trend for higher absolute errors in those exercise practitioners at an upper range of aerobic fitness. Indeed, from a clinical perspective, a small error at > 12 METs is much less relevant than a similar magnitude of error at the lower range of aerobic fitness. Although it was not among the main objectives of the study, the presence of a significant yet moderate association — r values ranging from 0.63 to 0.71 — between measured (CPET) aerobic fitness and non- aerobic (SRT or maximal muscle power) fitness, with all these variables clearly and independently associated with all-cause mortality, 2,32,34 is a new finding that should be further explored in upcoming epidemiological studies using CLINIMEX’s cohort. This study has several positive points: 1) the prospective design; 2) the large and varied sample in terms of sex, clinical condition, ergometer and levels of aerobic fitness (as often seen in clinical practice); 3) all data collected under well-controlled conditions by only four specialized physicians; 4) the use of a gold standard for criterion validity and; 5) the possibility of assessing the influence of several other variables, including results of two assessment tools of non-aerobic physical fitness. On the other hand, the study also has some limitations: 1) the sample was primarily comprised of white subjects with high educational level and/or upper socioeconomical class; and 2) only four specialized physicians applied the C-AFQ. Both limitations could have influenced the external validity of our results and only future studies with other populations and a larger number of applicants will be able to show if the present results can be generalized or not.