Regular physical activity is associated with a broad range of health benefits but whether it can reduce complications from COVID-19 is unclear.
International guidelines recommend the attainment of at least 150 – 300 minutes/week of moderate intensity physical activity for health benefits. It is known, for example, that regular physical activity improves immune function and decreases inflammation which is one of the main contributors to the lung damage caused by COVID-19. Is it possible therefore, wondered a team from the Department of Family and Sports Medicine, Kaiser Permanente Medical centre, California, US, that achieving the recommended amounts of physical activity might positively impact on the severity of COVID-19? The researchers retrospectively reviewed electronic health records in the two years prior to the March 2020 lockdown and included patients aged 18 years and over with a positive COVID-19 test or diagnosis between January and October 2020 and who had at least 3 exercise vital sign measurements between March 2018 and 2020. The exercise vital sign data was based on responses to questions enquiring about the weekly frequency and duration of exercise and was recorded in the electronic health record. Patients with at least 3 documented recordings within 2 years before the national lockdown were included in the analysis. The researchers then categorised individuals into one of three groups: those who met the physical activity guidelines (> 150 minutes/week), inactive individuals (0 – 10 minutes/week based on all assessments) and those with some activity (11 – 149 minutes/week). The primary outcomes examined for the study were hospitalisations, admission to intensive care (ICU) and death due to COVID-19. Data on comorbidities were also collected and adjusted for in regression models.
There were 48,440 patients with a positive PCR COVID-19 test and for whom at least three exercise reading were available within 2 years of the national lockdown. The mean age of the sample was 47.5 years (61.9% female), of whom only 6.4% were consistently meeting the physical activity recommendations and 14.4% were consistently inactive. Among the whole cohort, 8.6% were hospitalised because of COVID-19, 2.4% admitted to ICU and 1.6% died. In adjusted models, compared to those consistently meeting the physical activity requirements, those deemed consistently inactive had a 2.26-fold higher risk of hospitalisation (odds ratio (OR) = 2.26, 95% CI 1.81– 2.83), being admitted to ICU (OR = 1.73) or of death (OR = 2.49) because of COVID-19. In addition, those doing some activity, were still at a higher risk of hospitalisation (OR = 1.89), admission to ICU (OR = 1.58) and death (OR = 1.88) although these risks were lower than those who were inactive.
The authors note how this appears to be the first study to demonstrate how physical activity is an important and modifiable risk factor for severe outcomes in those with COVID-19. In fact, after adjustment for comorbidities, it appeared that physical inactivity was a more significant factor for severe outcomes than both smoking and other chronic diseases. The also noted how their results were especially important given the increased barriers to physical activity imposed by the lockdown.
Sallis R et al. Physical inactivity is associated with a higher risk for severe COVID-19 outcomes: a study in 48 440 adult patients. Br J Sports Med 2021