Regular exercise reduces the risk of COVID-19 infection and severity, including hospital admission and death.
In a new research project published in the British Journal of Sports Medicine, pooled data analysis of available evidence indicates that regular exercise – 150 minutes of moderate exercise or 75 minutes of vigorous exercise – provides the best protection again COVID-19 infection and severity.
Previous research has illuminated that physical activity can lessen both the risk of infection and the severity of respiratory infections due to its ability to bolster the immune system.
Studying almost 2 million adults around the world
The link between regular exercise and COVID-19 is misunderstood but likely involves both metabolic and environmental factors. This drove the researchers to attempt to quantify the threshold of regular exercise that may be required to reduce the impact of infection and associated hospital admission and death.
The researchers analysed three major databases for relevant studies published between November 2019 and March 2022, and from an initial haul of 291, pooled the results of 16. The studies included 1,853,610 adults, with over half being women and an average age of 53. The majority of the studies were observational and took place in South Korea, Iran, Canada, the UK, Spain, Brazil, Palestine, South Africa and Sweden.
Discovering the link between regular exercise and COVID-19
The analysis illuminated that those partaking in regular exercise weekly had an 11% lower risk of infection with SARS-CoV-2. They also found a 36% lower risk of hospital admission, a 44% reduction in severe COVID-19 illness, and a 43% lower risk of death from COVID-19 compared to physically inactive peers.
The maximum protective effect occurred at around 500 Metabolic Equivalent of Task (MET) minutes a week, after which there were no further improvements. METS describe the amount of energy (calories) expended per minute of physical activity, and 500 of them are equivalent to 150 minutes of moderate or 75 minutes of vigorous regular exercise.
Despite their compelling findings, the researchers cautioned that the analysis included observational studies, differing study designs, subjective assessments of regular exercise levels, and concerned only the Beta and Delta variants of SARS-CoV-2 rather than the Omicron. However, the researchers noted there are plausible biological explanations for their discovery. Regular moderate-intensity exercise may boost the body’s anti-inflammatory responses, as well as cardiorespiratory and muscular fitness, all of which may explain the beneficial effects of COVID-19.
They concluded: “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.”
