Adult cardiorespiratory fitness changes during the COVID-19 pandemic estimated by non-exercise \:V̇O2max equations

Physical activity patterns have reverted to pre-pandemic norms as social distancing measures have improved. However, the understanding of the impact of the COVID-19 pandemic on adult cardiorespiratory fitness (CRF) remains limited. Our questions were as follows: Has the COVID-19 pandemic continued to affect adults’ CRF even after 2 years? Is a longitudinal study-based equation more suitable than a cross-sectional analysis for estimating the pandemic’s impact on CRF? We aimed to develop non-exercise cross-sectional and longitudinal equations for predicting treadmill maximal oxygen uptake ( \:V̇ O2max) that incorporate cardiovascular risk factors (CVRFs). We then compared CRF changes during the pandemic using these approaches, providing crucial insights into the long-term effects of the pandemic on cardiorespiratory fitness. Data from 1,295 Epidemiology and Human Movement Study participants were analyzed, with 498 who underwent at least two cardiopulmonary exercise tests over a median of 2 years. Linear multivariate hierarchical and mixed-effects models were used to develop the equations. The best models were applied to estimate CRF changes during the pandemic in 405 adults who completed a survey. Age, weight, height, sex, hypertension, diabetes, dyslipidemia, obesity, insufficient physical activity, smoking status, and beta-blocker usage were key determinants of \:V̇ O2max. The predictors explained 72% and 56% of the \:V̇ O2max total variability in the best cross-sectional and longitudinal equations, respectively. \:V̇ O2max during the pandemic, obtained from the questionnaire, was significantly lower than pre-pandemic values (P < 0.05) in both models. However, the decrease adjusted for age was more pronounced (P < 0.05) in the cross-sectional model (-0.82 mL kg-1 min-1) than in the longitudinal model (-0.63 mLO2 kg-1 min-1). Our findings demonstrate that demographic and anthropometric factors, CVRFs, and beta-blockers can reasonably estimate \:V̇ O2max in both equation types. Importantly, both approaches effectively captured the pandemic’s detrimental impact on Brazilian adults’ CRF, with the cross-sectional model showing significantly greater changes. This underscores the importance of promoting individual physical exercise during pandemic-related restrictions, given the observed associations with cardiovascular health.