Regular Exercise Can Reduce Your Risk of a Severe COVID-19 Case

Apart from receiving the vaccine, getting your daily steps may be the best thing you can do to protect yourself from severe COVID-19.

In a new study of nearly 50,000 Californians who developed COVID-19, researchers found that people who did regular physical activity were less likely to end up in the ICU or die from the disease. The findings were published in the British Journal of Sports Medicine last week.

Compared with people who were active for at least 150 minutes per week, those who were regularly sedentary were about twice as likely to be hospitalized and two-and-a-half times more likely to die from COVID-19.

Exercise can greatly decrease your likelihood of becoming gravely ill from the disease, lead study author Robert Sallis, MD, a family and sports medicine doctor at the Kaiser Permanente Fontana Medical Center in California, tells Verywell. U.S. physical activity guidelines call for 150 minutes of moderate exercise per week. To reach that goal, you can start with small activities, like walking your dog and ditching the elevator for the stairs.

Apart from being vaccinated, “doing regular physical activity is the single best thing you can do to try to protect yourself,” Sallis says.

How Exercise Helps Us

Exercise is known to help people fight off viral infections by strengthening the immune system, heart, and lungs. Studies even show that being aerobically fit increased the effectiveness of the influenza vaccine in some people.

When we exercise, our heart rate increases, and blood flows quickly through the body. This signals to immune cells in places like the spleen and bone marrow lymph nodes to come out and circulate the body at a higher rate than normal. This increased immune surveillance can drive down infections.

“The chance of dealing with the pathogens and the viruses and the bacteria—the bad guys—increases because there's this patrolling activity of the immune cells,” David Nieman, DrPH, FACSM, professor of biology at Appalachian State University in North Carolina, tells Verywell.

Physical Activity Lowers Risk

When patients come through the Kaiser Health System, health providers ask about their average weekly physical activity. Information about the duration of and consistency with which they exercise is recorded in the online health record, along with their other vital signs. Sallis says he believes Kaiser has one of the largest electronic health records systems that includes exercise vital signs.

The research team collected anonymized data from 48,440 adults for whom Kaiser had at least three records of exercise and who had been diagnosed with COVID-19. They grouped the subjects by activity level. The least active group exercised for 10 minutes or less most weeks and the most active group reached the 150-minute-per-week threshold.

They found that people in the least-active group were twice as likely to be hospitalized for COVID-19, and two-and-a-half times more likely to die from the disease, compared with those in the most active group.

The researchers used a statistical method to parse out the effect of exercise on COVID-19 outcomes compared with other commonly associated risk factors, like diabetes and a high BMI.

“It's not just its effect on lowering the risk for all of these other chronic diseases—taken apart from that, [physical activity] still has a very profound effect,” Sallis says.

In a study published in February in the International Journal of Obesity, researchers found that, regardless of whether they had obesity, people who walked briskly were less likely to develop severe COVID-19 compared to those who walked slowly. The Kaiser study builds on this—indicating that how often you exercise may be more important than other risk factors for developing severe COVID-19. And by tracking sustained exercise, rather than general fitness, the research shows that building an exercise routine can have significant effects on health.

“This is great data, and it just adds to the work that has consistently shown that physically active people are less prone to a severe case of COVID-19,” Nieman says.

Improving Your Health

To best strengthen your immunity and support your body, it’s important to be physically active for at least 150 minutes per week. This could include activities like jogging, walking briskly in a hilly area, biking, swimming, or even strenuous gardening.

“It really comes down to getting your heart rate up, getting a bit winded, and holding that for 30 minutes,” Sallis says. “You should be walking briskly enough that you couldn't sing while you're walking, so you're a bit winded, but not so intensely that you couldn't talk.”

It doesn’t matter much how you break it up—three 10-minute walks in a day are as good as one 30-minute walk, Sallis says. While it’s best to form a habit of exercising most days of the week, going on long walks a few days a week appears to be similarly effective.

However, Nieman notes that exercising regularly gives your immune cells more opportunity to patrol your body and fight infections. “It can't just be strolling through a store—it needs to be where you're out there, transporting yourself at a good clip,” Nieman says.

It’s important to note that while exercise is a great preventative measure, it won’t necessarily help you fight illness once you are sick. In fact, exercising too rigorously while sick may make the infection worse. Nieman says if you do feel sick to rest until your symptoms are gone, and then slowly get back into an active routine.

“Exercise is great for preventing these respiratory illnesses, but it is not a drug to treat it,” Nieman says.

If you’re concerned about your chances of developing a bad case of COVID-19—especially if you’re not yet vaccinated—it’s a good idea to think about how you can be more active.  

“We all have time in our day … we can fit it in just like we have time to brush our teeth and take a shower,” Sallis says. “This is your medicine. You’ve got to take it.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.