Physical activity and risk of infection, severity and mortality of COVID-19: a systematic review and non-linear dose-response meta-analysis of data from 1 853 610 adults

Objective To quantify the association between physical activity and risk of SARS-CoV-2 infection, COVID-19-associated hospitalisation, severe illness and death due to COVID-19 in adults. Design A systematic review and meta-analysis. Data sources Three databases were systematically searched through March 2022. Eligibility criteria for selecting studies Peer-reviewed articles reporting the association between regular physical activity and at least one COVID-19 outcome in adults were included. Risk estimates (ORs, relative risk (RR) ratios or HRs) were extracted and pooled using a random-effects inverse-variance model. Results Sixteen studies were included (n=1 853 610). Overall, those who engaged in regular physical activity had a lower risk of infection (RR=0.89; 95% CI 0.84 to 0.95; I-2=0%), hospitalisation (RR=0.64; 95% CI 0.54 to 0.76; I-2=48.01%), severe COVID-19 illness (RR=0.66; 95% CI 0.58 to 0.77; I-2=50.93%) and COVID-19-related death (RR=0.57; 95% CI 0.46 to 0.71; I-2=26.63%) as compared with their inactive peers. The results indicated a non-linear dose-response relationship between physical activity presented in metabolic equivalent of task (MET)-min per week and severe COVID-19 illness and death (p for non-linearity <0.001) with a flattening of the dose-response curve at around 500 MET-min per week. Conclusions Regular physical activity seems to be related to a lower likelihood of adverse COVID-19 outcomes. Our findings highlight the protective effects of engaging in sufficient physical activity as a public health strategy, with potential benefits to reduce the risk of severe COVID-19. Given the heterogeneity and risk of publication bias, further studies with standardised methodology and outcome reporting are now needed. PROSPERO registration number CRD42022313629.

Automated summary

There is an association between physical activity and the risk of SARS-CoV-2 infection, COVID-19 hospitalization, severe illness, and death. Regular physical activity is associated with a lower risk of these adverse COVID-19 outcomes.