Adults in the U.S. over the age of 45 who exercised before the pandemic are at a reduced risk of contracting COVID-19 infection and hospitalization, a study has revealed.

Senior adults who followed recommended exercise guidelines before the pandemic had significantly lower odds of being infected or getting hospitalized from COVID-19 compared to those who did not follow guidelines, according to the study published in Jama Network Open.

Studies have shown that following the recommended guidelines of at least 150 minutes/week of moderate to vigorous physical activity may help mitigate the effects of cardiovascular disease, cancer, type 2 diabetes, and other chronic conditions. Exercise is also linked to improved immunity, reduced age-related immunosenescence (waning of immunity), and low-grade systemic inflammation.

In a recent large-scale study involving 61,557 adults, researchers examined if physical activity could guard against infectious diseases such as COVID-19. The participants were of the average age of 76 and were part of three randomized clinical trials: a Cocoa Supplement and Multivitamin Outcomes Study, a Vitamin D and Omega-3 Trial, and a Women's Health Study.

Through surveys filled in by the participants before the pandemic (Dec. 31, 2019), researchers assessed the lifestyle factors, and time spent on activities such as walking, running, biking, and climbing stairs. Based on the physical activity levels, participants were categorized as inactive (0 minutes per week of moderate-intensity exercise), insufficiently active (60 minutes), or sufficiently active (150 minutes).

The analysis showed that 20.2% of the participants were inactive, 11.4% were insufficiently active, and 68.5% were sufficiently active.

"The COVID-19 pandemic provided a very unique opportunity to look at a potential benefit of physical activity from data that was collected before it began," said lead author Dennis Muñoz Vergara in a news release.

The respondents were asked to fill in surveys about their COVID-19 diagnoses or hospitalizations between May 2020 to May 2022. During the period, 5,890 participants contracted COVID-19, and 626 of them were hospitalized with the infection.

"After controlling for demographics, BMI, lifestyle factors, underlying illnesses, and medications, compared with inactive individuals, those who were insufficiently active had no significant reduction in infection or hospitalization, while those sufficiently active had a significant reduction in infection and hospitalization," the researchers wrote.

"This large, unique study in older adults as they navigated the onset of the pandemic provides important support for physical activity in preventing COVID-19 infection and hospitalization that may extend more broadly to enhanced immune function and lessening vulnerability to infections," said senior author Howard Sesso in the news release.