Being physically active before pandemic reduced odds of having COVID-19

Key takeaways:

• Older adults who were sufficiently active had 10% lower odds of developing COVID-19 vs. those who were inactive.
• In subgroup analyses, only sufficiently active women had decreased odds of infection, not men.

Higher physical activity levels before the COVID-19 pandemic were associated with lower odds of developing and being hospitalized for COVID-19 in older adults, according to a recent study.

“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,” Dennis Muñoz-Vergara, DVM, MPH, MS, PhD, an instructor at Brigham and Women’s Hospital, said in a press release.

Prior research reported that regular moderate-to-vigorous physical activity reduced the risk for COVID-19, in addition to risks for mortality, severe disease and hospitalization.

“However, significant gaps exist in the evidence that physical activity protects against infectious diseases,” Muñoz-Vergara and colleagues wrote in JAMA Network Open.

They also added that the generalizability of previous studies to older adults is limited.

In the current study, the researchers assessed a cohort of 61,557 adults aged 45 years or older that they assembled from three randomized controlled trials. All patients had completed prepandemic physical activity questionnaires.

The adults, with a mean age of 76 years, were divided into three categories based on prepandemic weekly metabolic equivalent (MET) hours:

• inactive: participants who had 0 to 3.5 MET hours;
• insufficiently active: participants who had greater than 3.5 but less than 7.5 MET hours; and
• sufficiently active: participants had at least 7.5 MET hours.

From May 2020 through May 2022, there were 5,890 confirmed cases of COVID-19 in the study population, including 626 hospitalizations.

Muñoz-Vergara and colleagues found that sufficiently active participants had 10% lower odds of developing COVID-19 (OR = 0.9; 95% CI, 0.84-0.97) and 27% lower odds of being hospitalized from infection (OR = 0.73; 95% CI, 0.6-0.9) vs. those who were inactive.

Meanwhile, in subgroup analyses, only women who were sufficiently active had decreased odds of infection (OR = 0.87; 95% CI, 0.79-0.95) compared with inactive women. No such association was found in men.

The researchers highlighted several potential reasons for the findings, such as physical activity enhancing immune surveillance mechanisms.

“Physical activity increases levels of salivary [immunoglobulin A], an antibody known to protect against respiratory viruses,” they wrote. “Still, the exact mechanisms by which physical activity and more specific components of physical activity (eg, frequency, duration, intensity and type) affect these physiological pathways warrant further investigation.”

Muñoz-Vergara and colleagues also noted that greater outcomes seen in women could be “potentially due to differences in respiratory system physiology.”

They concluded that more research, “including quantitative control of physical activity parameters, broader racial and ethnic diversity, and information from other potential confounders,” is needed.

References:

• Muñoz-Vergara D, et al. JAMA Netw Open. 2024;doi:10.1001/jamanetworkopen.2023.55808.
• Study finds high levels of physical activity lowered risk of developing COVID-19 infection and hospitalization. https://www.brighamandwomens.org/about-bwh/newsroom/press-releases-detail?id=4651. Published Feb. 13, 2023. Accessed Feb. 13, 2023.