Exercise Is Medicine for Immune Function: Implication for COVID-19.

This review supports that physical activity improves immunosurveillance and has the potential to counter COVID-19 infection and symptomatology at three prevention levels. At the primary prevention level, several lines of evidence support that physical activity is an immune system adjuvant in combating infectious diseases. Recent epidemiological studies indicate that regular physical activity is associated with a reduced risk for COVID-19, similar to what has been reported for other respiratory infections. Although specific COVID-19-related studies are needed, data from investigations with other types of infectious agents, such as influenza, support the potential role of physical activity in augmenting COVID-19 vaccine efficacy (secondary prevention level). There is a growing awareness that COVID-19 can cause sustained morbidity in some patients, and physical training and rehabilitation (tertiary prevention level) can be directed toward improvement in physical fitness, quality of life, and immune health.