Exercise may strongly protect against poor COVID-19 outcomes

Woman walking dog under trees
Woman walking dog under trees

Collin Key / Flickr cc

Regular physical activity may substantially reduce the risk of COVID-19–related hospitalization, intensive care unit (ICU) admission, and death, suggests an observational study of nearly 50,000 people published yesterday in the British Journal of Sports Medicine.

Kaiser Permanente Southern California researchers led the retrospective study, which involved linking the self-reported physical activity levels of 48,440 adult patients who had at least three exercise vital sign measurements in the 2 years preceding the pandemic to their risk of severe coronavirus outcomes.

Used at every outpatient visit at Kaiser Permanente since 2009, exercise vital sign measurements include average number of days a week of moderate to strenuous exercise and duration of that exercise.

The patients, who were diagnosed as having COVID-19 from Jan 1 to Oct 21, 2020, reported their physical activity as consistently inactive (0 to 10 minutes a week), some activity (11 to 149 minutes), or consistently meeting guidelines (more than 150 minutes).

More important than other modifiable risk factors

The researchers found that, compared with COVID-19 patients who consistently met exercise guidelines, those who were consistently inactive were at 2.26 times the risk of hospitalization, 1.73 times the risk of ICU admission, and 2.49 times the risk of death from their infections.

Similarly, compared with COVID-19 patients who reported some physical activity, those who were consistently inactive were 1.20 more likely to be hospitalized, 1.10 times more likely to be admitted to the ICU, and 1.32 times more likely to die.

Consistent inactivity was the third most important risk factor for COVID-19 death, behind only age older than 60 years and previous organ transplant. It was more important than even smoking, obesity, diabetes, high blood pressure, cardiovascular disease, and cancer.

Even inconsistently inactive patients were at lower risk for severe coronavirus illness than those who were consistently inactive. Among all patients, 8.6% were hospitalized, 2.4% received ICU care, and 1.6% died.

Of all patients, 6.4% said they were consistently active, and 14.4% were consistently inactive, while the rest reported some physical activity. White patients were more likely to report consistently meeting physical activity guidelines (10%) than Asian (7%), Hispanic (6%), and Black (5%) patients.

Roughly half of the patients had no underlying medical conditions, while 18% had one such condition, and 32% had at least two. Patients who had chronic diseases or who smoked were less likely than others to report consistent or some activity. Average body mass index was 31 kg/m2, which is classified as obese. Median age of the racially diverse patients was 47 years, and 61.9% were women.

'A medicine that everyone should take'

The authors noted that education about the benefits of physical activity has largely been absent amid the pandemic and that public health mitigation measures likely reduced exercise levels even more as people were asked to stay home.

"Consistently meeting physical activity guidelines was strongly associated with a reduced risk for severe COVID-19 outcomes among infected adults," the authors concluded. "The potential for habitual physical activity to lower COVID-19 illness severity should be promoted by the medical community and public health agencies."

In a Kaiser Permanente press release, senior author Deborah Rohm Young, PhD, said she was surprised by how strongly inactivity and poor COVID-19 outcomes were linked. "Even after we included variables such as obesity and smoking in the analysis, we still saw inactivity was strongly associated with much higher odds of hospitalization, ICU admission, and death compared with moderate physical activity or any activity at all," she said.

Lead author Robert Sallis, MD, said that the study shows how important regular physical activity is to health during the pandemic and beyond. "Walk 30 minutes a day, 5 days a week at a moderate pace and that will give you a tremendous protective effect against COVID-19," he said, adding that walking at a moderate pace should leave walkers too out of breath to sing but not to talk.

"I continue to believe that exercise is medicine that everyone should take—especially in this era of COVID-19."

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