The COVID-19 pandemic decreases cardiorespiratory fitness. A 3-year follow-up study in industry

Abstract

Abstract Purpose: This study aimed to determine if maximal oxygen uptake (V̇O2max), resting heart rate (RHR), and self-reported leisure- time moderate to vigorous physical activity (MVPA) changed over a 3-year follow-up (FU) among industrial workers during restrictions of outdoor movement and the concurrent closure of fitness centres due to the COVID-19 pandemic. Methods: We assessed cardiorespiratory fitness (CRF) among workers in industry in August 2018 and in August 2021. The last 17-18 months of the 3-year FU coincided with the COVID-19 pandemic. Data from 86 participants were collected; demographics by questionnaire and cardiovascular outcomes from medical examination: V̇O2max, RHR, and fat mass (%). At both time points, workers reported on their leisure-time MVPA. To assess changes in health outcomes, we applied a linear mixed model, adjusting for baseline (BL) age, sex, pack-years, shift work, and a 5-month plant shutdown. In a second analysis, we adjusted for actual age instead of BL age. Results: V̇O2max decreased from 39.6 ml/kg/min at BL to 34.0 at FU, a reduction of 5.6 ml/kg/min (95%CI, -7.6,-3.7). When adjusted for actual age, the corresponding figure for V̇O2max was 5.4 ml/kg/min, (95%CI, -7.4,-3.4), an annual loss of 4.6%. RHR increased from 61.3 to 64.4 beats per minute (95%CI, 0.8, 5.4). Self-reported MVPA decreased by 43.9 min/week, (95%CI, -73.5,-14.4). Conclusion: We observed a significant decrease in V̇O2max, an increase in RHR and a decrease in self-reported MVPA over the 3-year FU among industrial workers. These changes may be attributable to physical inactivity during the COVID-19 pandemic. ISRCTN42416837, date of registration 25.10.2018