Associations of pre-pandemic levels of physical function and physical activity with COVID-19-like symptoms during the outbreak

Background One’s physical function and physical activity levels can predispose or protect from the development of respiratory infections. We aimed to explore the associations between pre-pandemic levels of physical function and physical activity and the development of COVID-19-like symptoms in Swedish older adults. Methods We analyzed data from 904 individuals aged ≥ 68 years from the population-based Swedish National study on Aging and Care in Kungsholmen. COVID-19-like symptoms were assessed by phone interview (March–June 2020) and included fever, cough, sore throat and/or a cold, headache, pain in muscles, legs and joints, loss of taste and/or odor, breathing difficulties, chest pain, gastrointestinal symptoms, and eye inflammation. Muscle strength, mobility, and physical activity were examined in 2016–2018 by objective testing. Data were analyzed using logistic regression models in the total sample and stratifying by age. Results During the first outbreak of the pandemic, 325 (36%) individuals from our sample developed COVID-19-like symptoms. Those with slower performance in the chair stand test had an odds ratio (OR) of 1.5 (95% confidence interval [CI] 1.1–2.1) for presenting with COVID-19-like symptoms compared to better performers, after adjusting for potential confounders. The association was even higher among people aged ≥ 80 years (OR 2.6; 95% CI 1.5–4.7). No significant associations were found between walking speed or engagement in moderate-to-vigorous physical activity and the likelihood to develop COVID-19-like symptoms. Conclusion Poor muscle strength, a possible indicator of frailty, may predispose older adults to higher odds of developing COVID-19-like symptoms, especially among the oldest-old.