A Nonexercise Estimate of Cardiorespiratory Fitness Using a Symptom Questionnaire and Clinical Variables

Abstract

Cardiorespiratory fitness (CRF) has recently been classified as a primary risk factor, but determining CRF requires an exercise test. We applied a symptom questionnaire as part of a nonexercise model to estimate CRF (eCRF). We observed that eCRF provided mortality risks that were similar to those from maximal exercise testing.

Cardiorespiratory Fitness and Its Place in Medicine

“…Thus, for large population-based observational studies, non-exercise estimates generally appear to provide adequate reflections of CRF, although they are somewhat less powerful than directly measured CRF. Nevertheless, these and other studies applying non-exercise estimates of CRF [15,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]56] provide further confirmation of the power of CRF in predicting risk for adverse outcomes.…”

“…A synopsis of key studies that have developed multivariable models to estimate CRF from non-exercise data is shown in Table 1 (Ref. [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]). Several observations are notable from the table.…”

“…The most appropriate method to estimate CRF from non-exercise data will undoubtedly differ depending upon the context in which CRF is applied and the sample being studied. For example, applying a symptom questionnaire (such as the Veterans Specific Activity Questionnaire [ 24 , 39 ] or Duke Activity Status Index [ 50 ]) are suitable for clinically referred samples (the group for which they were developed), but most of the models have been derived from relatively healthy, asymptomatic subjects for whom these tools would not apply. Not all samples had physical activity patterns available, which is the key behavioral factor influencing CRF.…”

“…A rapid and reasonably accurate non-exercise estimate of CRF would be particularly useful when testing large populations or performing epidemiologic research, in which exercise testing of large numbers of participants is impractical. A growing number of studies have applied estimates of CRF derived from a non-exercise prediction model to estimate future risk of mortality, CVD events or cancer [ 15 , 39 , 53 , 54 , 55 ]. Notably, the risk reductions per each 1-MET higher non-exercise estimate of CRF have been demonstrated to be similar to those using measured exercise capacity from a treadmill or cycle ergometer (10–20%).…”

High Cardiorespiratory Optimal Point Values Are Related to Cardiovascular Mortality in Men Aged 46 to 70 Years: a Prospective Cohort Study

“…Cardiorespiratory fitness can be estimated by different methods, using either formulas based on exercise variables such as heart rate, cycling workload, or treadmill speed/incline achieved during exercise testing 8,9 or population-specific questionnaires, 10 such as the CLINIMEX Aerobic Fitness Questionnaire. 11 However, whenever possible, directly measured cardiorespiratory fitness obtained from a maximal cardiopulmonary exercise test (CPX) is preferable, controlling for interindividual variability in exercise mechanical efficiency and capacity.…”