Predicting Cardiorespiratory Fitness with a Cycle Ergometry Equation in Middle-Aged and Older Adults at Low and High Risk of Cardiovascular Disease.

Abstract

Low cardiorespiratory fitness (CRF) has consistently been associated with an increased risk of premature mortality and has been shown to be comparable with traditional cardiovascular disease (CVD) risk factors in terms of health outcomes. Thus, the purpose of this study was twofold: 1) to determine the accuracy of commonly proposed cycle ergometry equations to predict maximum oxygen uptake (pV̇O 2max ) in middle-aged and older adults and 2) to assess if the accuracy is affected by the presence of CVD risk factors. A total of 1255 participants (62.4 ± 6.9 yr; 62.9% male) were included. V̇O 2max was directly measured during an incremental maximal exercise test on a cycle ergometer. In addition, three non-gender- and gender-specific cycle ergometry equations (Storer et al., 1990; de Souza et al., 2015; and (FRIEND) Kokkinos et al., 2018) were used to pV̇O 2max . Both FRIEND and Storer equations showed pV̇O 2max with a low relative bias for both non-gender-specific (-0.81% ± 12.9% and -0.31% ± 13.1%, respectively) and gender-specific (women: -0.03% ± 13.6% and -3.31% ± 13.3%; men: -045% ± 11.5% and 0.61% ± 11.5%, respectively) equations. Bland-Altman results also showed no difference between measured and pV̇O 2max with excellent accuracy based on the Cb (0.99-1 and 0.98-1.0) and Lin's concordance correlation coefficient (0.91 and 0.89-0.92) scores for both FRIEND and Storer equations, respectively. The coefficient of determination ( R2 ) was high (0.83-0.86) displaying good accuracy with low root-mean-square error values. Both the Storer and the FRIEND cycle ergometry equations predicted CRF with good accuracy in adults at low and high risk of CVD. Using the gender-specific equations slightly improved the accuracy; however, the FRIEND equation performed better overall. Therefore, the FRIEND equation provides a practical and simple alternative to assess CRF in adults when the direct measurement of V̇O 2max is not feasible.