A sweeping new analysis from Norway has found that cardiorespiratory fitness—how well your heart and lungs power your body during exercise—may be a powerful shield against severe COVID-19 outcomes, though it doesn’t seem to stop the virus from infecting you in the first place. The study, part of the renowned Trøndelag Health Study (the HUNT Study), followed 48,821 adults with data on their fitness and physical activity collected between 2017 and 2019, before the pandemic even hit.
Researchers linked these pre-pandemic fitness levels to national COVID-19 records from February 2020 through September 2022. Over an average follow-up of 2.6 years, they documented 5,991 SARS-CoV-2 infections and 218 COVID-19–related hospitalizations. The takeaway? People with higher cardiorespiratory fitness were less likely to end up hospitalized from COVID-19, even after accounting for differences in leisure-time physical activity. However, neither fitness level nor physical activity seemed to change the odds of getting infected in the first place.
Fitness, Heart Health, and Virus Risks
The study used Poisson regression to crunch the numbers and found that while fitness can’t make you virus-proof, it does seem to make your body more resilient if you do catch COVID-19. This aligns with earlier research showing that cardiorespiratory fitness—often measured by VO2 max—is one of the strongest independent predictors of all-cause and cardiovascular mortality, regardless of factors like smoking or BMI. VO2 max naturally declines by about 5 to 10 percent per decade after age 30, and staying physically active can help slow that slide.
Broader Implications Amid Ongoing Virus Seasons
While COVID-19 activity is on a downward trend nationally, according to CDC updates as of February 27, 2026, hospitalizations for respiratory viruses like RSV and influenza remain a concern—especially among vulnerable groups. Another recent study in the U.S. highlighted that RSV infection, much like COVID-19, can trigger acute and long-term cardiorespiratory complications, with some risks staying elevated for up to 180 days after hospitalization.
Experts recommend regular aerobic activity—not just for pandemic protection, but for overall heart health and longevity at any age. WHO suggests aiming for at least 300 minutes of moderate activity weekly, though everyone’s needs and abilities will vary. The bottom line: while exercise alone won’t keep you from catching COVID-19 or other respiratory infections, keeping your heart and lungs in top shape could make a crucial difference if you do get sick.
