COVID-19’s affect on health is a rapidly developing situation. For the most up-to-date information, check in with your local health officials and resources like the Centers for Disease Control and Prevention (CDC) regularly. This story will be updated as more information becomes available.

Whenever Cate O’Shea Rivera feels a cold coming on, she typically goes for a run.

The activity, she says, seems to clear the sickness from her system. “I’ll come back, I’ll take a nice warm shower, and I’ll be breathing through my nose better,” says the 43-year-old Chicago resident.

But this April, when O’Shea Rivera developed a cough and shortly after tested positive for COVID-19, exercise, it seemed, had the opposite effect. As O’Shea Rivera quarantined in her bedroom and adjoining backyard for three weeks, she was determined to work out for 30 minutes a day—even if it meant walking laps to and from the closet, or strolling circles in the yard.

Yet the 12-time marathoner soon found that just five minutes of easy walking “kicked my ass,” leaving her breathless and exhausted. Afterward, she’d use an inhaler, crawl back into bed, and “just lay there for hours.”

By week two, O’Shea Rivera started feeling better, but just 10 to 15 minutes of walking or light movement continued to have the same effect: worsening symptoms, coughing, dizziness, and physical exhaustion.

O’Shea Rivera knew she needed to rest, but also felt like if she kept moving, she’d get stronger faster. Her internal medicine physician, however, told her to not to push it. “This isn’t a cold or the flu,” O’Shea Rivera recalls her doctor saying.

As it turns out, O’Shea Rivera’s physician was right to urge caution. According to new evidence, exercise can indeed make COVID-19 worse. For runners like O’Shea Rivera and other active people who generally turn to physical activity to boost circulation and feel better faster when they’re a little under the weather, this is new and urgent news, says Jordan Metzl, M.D., a sports medicine physician at Hospital for Special Surgery or (HSS) in New York City.

“This goes against my personal exercise philosophy that burpees cure pretty much everything and the advice I have given for 20 years that it’s okay to exercise through minor sickness symptoms,” Dr. Metzl says. “COVID-19 plays by different rules when it comes to sports and exercise.”

Here’s what you need to know.
Be vigilant about listening to your body right now.

Exercise is still very important for your health. Not only does moderate, regular activity keep your immune system strong, but it also helps prevent the underlying conditions that might increase your risk of more severe coronavirus complications such as obesity, high blood pressure, and diabetes.

Specifically, research finds that regular exercise may reduce the risk of acute respiratory distress syndrome (ARDS), a potentially deadly complication that affects between 3 and 17% of people who come down with COVID-19.

So definitely keep moving, but pay attention to how you feel. As athletes, we all have a lot of experience with tuning into the cues our bodies send to us. Don’t just blow off persistent fatigue as a bad day. “You need to be a very good body listener right now,” Dr. Metzl says.

Be especially mindful of unusual symptoms, adds Sunal Makadia, M.D., LifeBridge Health Director of Sports Cardiology in Baltimore.

“Check in with your doctor if you have shortness of breath, chest pain, heart palpitations like a fluttering or rapid heartbeat, lightheadedness, leg swelling, muscle pains, and/or unexplainable fatigue,” Dr. Makadia says. “Even if you find yourself suddenly unable to keep up with your usual exercise partners, that’s a red flag to stop and get tested.”

You also want to check your heart rate monitor, if you use one, Dr. Makadia adds. “If you’re hitting your peak heart rate unusually early in your [run] or having a hard time bringing your heart rate down, that’s a sign you should check in with your doctor.”

COVID-19 Symptoms
According to the CDC, people with these symptoms may have COVID-19. If you suspect you have COVID-19, stop exercising and get tested.
» Fever or chills
» Cough
» Shortness of breath or difficulty breathing
» Fatigue
» Muscle or body aches
» Headache
» New loss of taste or smell
» Sore throat
» Congestion or runny nose
» Nausea or vomiting
» Diarrhea
Even mild cases of COVID-19 can hurt your heart.

Being healthy, fit, and strong may help you avoid some of the more severe symptoms of COVID-19 like ARDS, but it doesn’t make you immune from some of the more insidious effects of the disease. And even if you only come down with a mild to moderate case, you are still at risk for myocarditis, inflammation of the middle layer of the heart wall, which can weaken the heart and lead to heart failure, abnormal heartbeat, or even sudden death.

This can happen even if you have no symptoms at all. In a recent study published in JAMA Cardiology, German researchers performed cardiac MRI testing on 100 adults who had recovered from COVID-19. About half of them had mild to moderate symptoms and 18% never had any symptoms. Though the testing was performed two to three months after their diagnosis and none of them had experienced heart symptoms related to the new coronavirus, 78 of them had structural changes to their hearts, and 60 had myocarditis.

Ironically, athletes might be at particular risk for this complication because intense activity during active infection—even if you’re showing no symptoms—may cause the virus to replicate at a faster rate, Dr. Makadia says.

“During training, you increase your cardiac output. If you’re infected, this could in theory increase the viral replication in the heart muscle. If that happens the higher viral load may increase your risk of cardiac harm in the form of myocarditis, arrhythmias, and heart failure,” he says.

It’s important to stop exercising immediately at the first sign of potential cardiac symptoms and get checked out by your doctor, advises Dr. Makadia.

Dr. Metzl agrees. “We had a dedicated athlete and CrossFit enthusiast in her early 30s come down with COVID-19 when the pandemic struck New York. She had lingering fatigue and sluggishness and thought she would go out for a run to feel better. She died of a heart attack. She was young and healthy and had no pre-existing cardiac history. It’s very important to be conservative with COVID-19,” he says.
Blood clots are a risk.

An equally scary COVID-19-related cardiovascular concern is blood clotting like deep vein thrombosis (DVT)—something active people may also be more likely to develop in part because of our low resting heart rates, which can cause blood to pool in our calves if we sit for prolonged periods of time, like a long car ride. Dehydration and injuries also raise the risk.

“We know that very intense exercise increases inflammation and affects clotting even if you don’t have other risk factors, which may be why some people who travel to marathons and other races and sit in cars for several hours afterward have a higher rate of blood clots, Dr. Makadia says.

COVID-19 also causes an increase in clotting and inflammation, he says. “The athletic population should be concerned about clotting as it relates to COVID. Hydration is key, as is early testing if you have COVID-19 symptoms, so that doctors can monitor clotting proteins in the blood.”

Though you want to take it easy and avoid working out if you’re COVID-19 positive, low-intensity activity like easy walking, or at least avoiding prolonged sitting, can provide some protection against DVT.

Calf pain, swelling, and/or tenderness are red flags to get checked. “Again, you need to pay attention to anything unusual,” Dr. Metzl says. “I cared for a cyclist who developed blood clots in both of her legs because of COVID-19 and nearly had to have one of her legs amputated. Now is the time to be extra careful and not blow off symptoms.”
Stop exercising completely for at least two weeks.

If you’ve been diagnosed with COVID-19, whether or not you have symptoms, you should not exercise for at least two weeks after receiving your positive test, Dr. Makadia says. “If you do have symptoms, you should avoid exercise for two weeks after your symptoms subside.”

“The real concern is that people can have a biphasic response,” Dr. Makadia explains. “You can get symptoms and then after a few days feel that you’ve recovered. But then a lot of people have a resurgence of symptoms, and it’s that second bout that can be really troublesome. That’s when they get significantly worse. We want to avoid that second bout. That’s where that two-week recommendation comes from.”

After that two-week period, you may need additional testing as you look to resume your usual activity, Dr. Makadia says. “Your doctor may want to do follow up tests like blood work to check if your heart has been affected by the virus, as well as other tests like an EKG, an echocardiogram, and possibly a stress test.”
Ease back into activity slowly after COVID-19.

Nobody wants people to stop exercising for good. Everyone wants people who have had COVID-19 to start exercising again safely. That’s why doctors like Dr. Metzl have started creating guidelines for the medical community to follow as we work our way through the pandemic.

“Everyone is unique and this disease affects everyone uniquely and can affect the whole body in many ways, so there is no absolute algorithm for resuming activity as there is for a sprained ankle,” says Dr. Metzl, who authored a recently published review article titled Considerations for Return to Exercise Following Mild-to-Moderate COVID-19 in the Recreational Athlete. “We just need to help people return to activity in a gradual stepwise manner.”

As a general rule, people who have had COVID-19 should be followed closely, especially in the first three to six months as they return to exercise programs, Dr. Metzl and his co-authors conclude in the study. “This is true for athletes who have had COVID-19 to any degree,” Dr. Metzl writes.

If you’ve had a mild case, then Dr. Metzl and his coauthors recommend working with your doctor and following a gradual guided activity modification plan such as the 50/30/20/10 rule developed by the National Strength and Conditioning Association and Collegiate Strength and Conditioning Coaches Association Joint committee.

In that plan, the first week back, you resume activity at a level that is reduced by at least 50% of your normal exercise load. For example, if you usually run 6 hours a week, you should adjust to just 3 hours per week, spread out evenly across seven days. The following week, if all is well, you can resume at a level that is 30% lower than your usual weekly total (about 4 hours per week for this example), followed by 20% the next week, and 10% the next week.

As always, continue to follow the expert-recommended safety guidelines for activity including running alone, physical distancing and planning routes that are not heavily populated, maintaining light to moderate intensity, regular hand-washing, wearing a face covering when you can’t maintain appropriate distancing (or bringing one with you in case of an emergency).

As for O’Shea Rivera, she’s regained some of the strength she lost in April, but still struggles to run nearly five months after contracting the virus. Instead, she’s been going on 3-mile, fast-paced walks, and even those leave her exhausted. Her mindset, for now, is to “keep plugging along” but also listen to her body.

“I just had to accept the fact that I’m not a runner right now,” she says. “I’m just sort of taking a sabbatical. I will get back out there hopefully next year.”