Ultrarunner Elise McDonnell of Fort Collins, Colorado had run the trail “a million times,” she said, but it was unusually hard now for the 41-year-old nurse to find her groove after fighting COVID-19 last August. McDonnell kept having to stop to catch her breath, forcing her to abort the run. By last November, she was able to have several good runs a week, thanks to a prescription for inhaled albuterol, but her breathlessness was overwhelming on other days. On top of that, her heart was beating much faster than usual, even at rest. As it turns out, McDonnell’s story is familiar to many runners trying to resume exercise with Long COVID.*

Energy Malfunction

The National Jewish Health’s Center for Post-COVID Care and Recovery in Denver, where McDonnell was directed by her doctor, has been actively investigating why exercise is so difficult for some people with Long COVID. In January, a study revealed that cell mitochondria, where energy is produced, can be changed by the coronavirus and no longer work properly. J. Tod Olin, M.D., M.S.C.S., one of the study authors, said it appeared that the mitochondria “were just less efficient at using the fuel.” The result is what many long-haulers are experiencing: excessive fatigue for their level of physical activity.

A Yale School of Medicine study found similar results in people who had mild COVID. When tested, they had normal heart and lung function, yet would still experience exercise intolerance. “There is some kind of abnormal flow across the muscle bed,” said study co-author Phillip Joseph, M.D. of Yale’s Pulmonary Vascular Disease Program, “where oxygen is just not being delivered appropriately or absorbed appropriately.” 

Resuming Exercise (Slowly)

Everyone’s experience with Long COVID is different, but the American College of Cardiology’s general guidelines advise a gradual return to normal exercise. If patients don’t have chest pain, shortness of breath, or similar symptoms, said Theodore Strange, M.D., Staten Island University Hospital’s chair of medicine, then “returning to exercise is not an issue, but one should take their time getting back up to a regular training schedule. If any symptoms do occur, then one must cut back and restart running at a slower pace.”

• Strange advises runners to do 50% of their normal mileage the first week, 70% the second and third weeks, and 90% the fourth week. You should be able to resume normal mileage by the fifth week. Should symptoms recur, however, including abnormal breathlessness, chest pains, and/or lightheadedness, you should get examined.
• Joseph recommends that you recognize the point at which you develop post-exertional symptoms and stay just under that limit when exercising. Progress should be gradual over weeks or months instead of attempted abruptly, since a recurrence or exacerbation of symptoms can set you back.

‘Light at the End of the Tunnel’

As for McDonnell, she has been working with Dr. Olin to increase her breathing and lung capacity. She says her walking and hiking distances have been steadily increasing, though on other days she finds simple household tasks exhausting. There are no issues with her heart, and she’s confident that her lungs will recover, though she does have lung scarring from COVID. “The decreased capacity is something that they’ve seen dissipate for pretty much everybody.”

McDonnell now has asthma as well. While she doesn’t know whether it will be temporary or permanent, she knows it’s a common and manageable condition. She has two blood clots, but blood thinning medications have been helping her feel much better and hike longer distances. “It does feel like there’s a light at the end of the tunnel,” she says, “and I can see longer hikes this summer and maybe even some running here and there.”

*Rothenberg, J. (2022, April 23). Take it slow when returning to running with long covid. The Washington Post. https://www.washingtonpost.com/health/2022/04/23/long-covid-return-to-running