April 19, 2021 -- Add another potential benefit to getting the recommended amount of physical activity each week: people who exercised regularly and then tested positive for SARS-CoV-2 were less likely to experience more severe COVID-19 outcomes, a new study shows.
Importantly, even people who could not realistically exercise 150 minutes or more per week still experienced significant benefits compared with people who said they exercised 10 minutes or less.
Compared with the most active people in the study — those who exercised 150 minutes or more every week — patients with COVID-19 who were "consistently inactive" were 226% more likely to be hospitalized, 173% more likely to be admitted to an intensive care unit (ICU), and 149% more likely to die.
"We strongly believe the results of this study represent a clear and actionable guideline that can be used by populations around the world to reduce the risk for severe COVID-19 outcomes, including death," study author Deborah Rohm Young, PhD, told Medscape.
The study was published online April 13 in the British Journal of Sports Medicine.
A Little Exercise Goes a Long Way
A more realistic strategy could make a bigger overall impact, Ross Arena, PhD, who was not affiliated with the study, told Medscape when asked to comment. "How many individuals who are sedentary can see making that leap to 150 or more minutes of physical activity a week?" A more effective message might be ‘something is better than nothing, and more is better,’" he said.
"Walking your dog is being physically active," added Arena, professor and head of the department of physical therapy at the University of Illinois at Chicago College of Applied Health Sciences.
"You don't have to run a marathon or go to a gym and run on a treadmill 60 minutes a day. Although that's great," he said. It is also good to move more and sit less.
Young and colleagues found, for example, that compared with people who reported exercising 11 to 149 minutes each week, the inactive group was 120% more likely to be hospitalized, 110% more likely to need critical care admission, and 132% more likely to die.
Classifying physical activity between 11 minutes to 149 minutes per week is "a pretty wide range and there is probably a way to tease that out more," Arena said.
"We are hopeful that the message that a little exercise can go a long way will be heard and acted upon," added Young, research scientist with the Kaiser Permanente Southern California Department of Research and Evaluation in Pasadena.
The Merits of Moving
So what is the connection? Regular exercise can improve immune function, for one. "We have known for a long time that immune function improves with regular physical activity, and those who are regularly active have a lower incidence, intensity of symptoms and death from viral infections," Young said.
Additional benefits include greater lung capacity and improved cardiovascular and muscle function "that may serve to lessen the negative impacts of COVID-19," she said.
"To put it simply, exercise is medicine. If you have a better baseline cardiac and pulmonary function — as you would expect from someone who meets physical activity guidelines — then it stands to reason you can better withstand the stressor of COVID-19 that impacts many body systems," Monica Verduzco-Gutierrez, MD, chair of the Department of Rehabilitation Medicine at the Long School of Medicine at UT Health San Antonio in Texas, told Medscape.
To learn more, Young, lead author Robert Sallis, and their colleagues evaluated 48,440 adults in the Kaiser Permanente system. Each had a positive COVID-19 test or diagnosis between Jan. 1 and Oct. 21, 2020. Their average age was 47 years, and 62% were women.
The researchers also required that patients have at least three outpatient visits with exercise assessments between March 19, 2018, and March 19, 2020. The majority of participants were in the "some physical activity" category, with only 6.4% meeting US physical activity recommended levels and another 14.4% consistently inactive.
Higher Odds of Poor Outcomes
"I did not expect the odds ratios to be as strong as we found, particularly after controlling for known risk factors for COVID-19, especially obesity status," Young said. She and colleagues also adjusted for other underlying conditions, age, sex, race, and smoking status.
"It's a great study," Arena said. "It builds upon this evidence base that is quickly growing in the COVID pandemic era where lifestyle is tremendously important. Leading a healthy lifestyle protects you from chronic disease but also from complications with viral infection."
Previous research has pointed to similar benefits between physical activity and COVID-19 outcomes. A study published first as a preprint in May 2020 evaluated how lifestyle and other factors could affect infection risk. The British Biobank study included 387,109 adults in the United Kingdom. These researchers also found that physical activity was a very strong predictor of less severe complications with COVID-19.
Another research group demonstrated in a January 2021 study that greater exercise capacity, estimated from grade and speed on a treadmill, was also a significant predictor of lower risk for COVID complications.
A Lockdown on Physical Activity?
Education about the benefits of physical activity and advice to maintain or increase physical activity during the pandemic in the United States has been "essentially absent," the researchers note.
Young said, "The potential for regular physical activity to lower COVID-19 illness severity should be promoted by the medical community and public health agencies."
"People are moving even less now," Arena said. "The big concern is does this become the new norm after we emerge from the pandemic?" He and colleagues published a "Tale of Two Pandemics" commentary earlier this year examining the interplay between COVID-19 and the global inactivity and sedentary behavior trends.
"The magnitude of risk for all outcomes associated with being consistently inactive exceeded the odds of smoking and virtually all the chronic diseases studied in this analysis," the researchers add. This finding could indicate that "physical inactivity may play a crucial role as a risk factor for severe COVID-19 outcomes."
Challenging or Not, Still a Modifiable Risk Factor
" Physical inactivity was the third highest risk factor — only behind advanced age and history of organ transplant — for patients with COVID-19 ending up being hospitalized, admitted to the ICU, or dying," Verduzco-Gutierrez said.
"You can’t change your risk factor of advanced age — unfortunately — but you can increase your physical activity and decrease your risk of severe COVID," added Verduzco-Gutierrez, who also serves on the American Academy of Physical Medicine and Rehabilitation Inclusion and Engagement Committee and as director of the post-COVID recovery clinic at the University of Texas Health Science Center at San Antonio and at University Health.
"The next step would be to look at if physical inactivity is connected to patients suffering from long COVID," she said.