There might be another reason to be physically active after a new COVID-19 study.

A recently published large-scale U.S. study has found that a lack of exercise is associated with having more severe COVID-19 infections and death. That risk was surpassed only by older age and organ transplants.

The research was published online in the British Journal of Sports Medicine.

Scientists conducted the study “to compare hospitalization rates, intensive care unit (ICU) admissions and mortality for patients with COVID-19 who were consistently inactive, doing some activity or consistently meeting physical activity guidelines,” they wrote in the article.

The observational study involved 48,440 adult patients diagnosed with COVID-19 from January 1, 2020 to October 21, 2020 who had a minimum of three exercise vital sign measurements from March 19, 2018, to March 18, 2020.

Patients self-reported their physical activity levels. Consistently inactive meant they were active from 0 to 10 minutes each week, some activity meant they’d been active between 11 and 149 minutes each week and consistently meeting guidelines meant they’d engaged in 150 minutes or more of weekly activity.

Researchers linked each patients’ reported physical activity levels to the risk of hospitalization, ICU admission and death after being diagnosed with COVID-19.

They found that patients who had COVID-19 and were consistently inactive in the two years leading up to the pandemic were twice as likely to be admitted to a hospital compared to patients who consistently met physical activity guidelines. They also were 73% more likely to need intensive care, and more than twice as likely to succumb to the disease.

“It is notable that being consistently inactive was a stronger risk factor for severe COVID-19 outcomes than any of the underlying medical conditions and risk factors identified by (The Centers for Disease Control) except for age and a history of organ transplant,” researchers wrote in their conclusion. “In fact, physical inactivity was the strongest risk factor across all outcomes, compared with the commonly cited modifiable risk factors, including smoking, obesity, diabetes, hypertension, cardiovascular disease and cancer.”

“We recommend that public health authorities inform all populations that short of vaccination and following public health safety guidelines such as social distancing and mask use, engaging in regular (physical activity) may be the single most important action individuals can take to prevent severe COVID-19 and its complications, including death,” they added.