Respiratory Symptoms & Athletes
COVID is primarily a respiratory virus. The most common symptoms include cough and shortness of breath. We know that those who require hospitalization commonly require respiratory or breathing support.
How Lungs Function: Every cell in the body requires oxygen to function. When we breathe in air through our mouth and nose it travels through our respiratory tract to the lungs where oxygen is removed from the air through a thin cellular membrane and transfers to the bloodstream. The bloodstream also brings carbon dioxide, a waste product of the cells, back to the lungs which can then be exhaled. This oxygen in the blood is then shuttled throughout the body to allow for bodily functions. One cannot survive without functioning lungs. Additionally, lung disease or small deficits in lung function can make exertion such as running, walking, and sports difficult. These deficits can occur in any part of the respiratory system including the lung tissue itself, the blood vessels that transport oxygen and carbon dioxide, and the muscles and bones that allow us to easily breath in and out. All of these anatomical structures can become disrupted with illness or injury.
Acute Lung Injury and COVID: While we are still learning about COVID-19, we do know that lung-related symptoms are among the most common. The lungs can be damaged in COVID from the virus itself, from the bodies’ inflammatory response, and even from treatments. In the case of most viral cases of pneumonia, both lungs tend to be involved with COVID infections. During the infection, the lungs can fill with fluid and inflammatory cells and mediators. These mediators damage the lung cells and make it difficult to breathe normally. When work of breathing gets to be too difficult, people sometimes require respiratory support which can be delivered with nasal tubes, masks, mechanical ventilators, or even heart- lung bypass machines. While the majority of young and healthy people who contract COVID will not require this degree of support, COVID is sending more young and healthy people to the hospital than typical viruses. Young patients have required all of the above types of respiratory support and some have even had a lung transplant due to COVID.
Post-Infection Lung Symptoms: At this time we do not have a lot of data on athletes returning to sport post-COVID infection. The return to normal respiratory function likely will be determined by the severity of the infection and deconditioning in each athlete. Some athletes who suffered from COVID are reporting shortness of breath with exercise upon returning. This could be due to lung damage, deconditioning, and other factors. It seems likely that the time to return to play for those who have suffered respiratory symptoms will be higher than with typical respiratory viruses due to the severity of COVID and that people seem to be ill longer than with typical viruses.
Any athlete who requires hospitalization or respiratory support will likely be out for a prolonged period as both their lungs and the rest of their body recovers. With COVID, we are seeing that those who survive a hospitalization require support longer than is typical with viral lung infections (weeks to months). Sometimes people will require support with oxygen even once home as they recover. After the lungs recover, athletes will face issues with deconditioning. Athletes require conditioning in strength, aerobic fitness, and coordination. All of these will be negatively affected by COVID, even more so if the athlete requires hospitalization. Even after recovery, an athlete may not feel back to their baseline for weeks to months.
Permanent Lung Conditions Related to COVID: While typically viral illnesses do not tend to cause lasting damage except in severe situations, COVID appears to occasionally cause lung scarring (fibrosis). When the normal lung cells are replaced with scar tissue, the oxygen may not transfer to the bloodstream efficiently and it may be harder for one to work to breathe if the lung tissue becomes stiff or less elastic. While it is likely that those with more severe illness will have more severe scarring, a troubling finding for COVID is that even asymptomatic people have been demonstrated to have a scar in their lungs on advanced imaging. Depending on the degree of scar this could make returning to sports and athletic activity much more difficult. As scar typically does not improve with time, it is likely that some will not be able to return to their previous level of activity and could even end up permanently disabled.
While it seems that those who were sicker due to COVID, had pre-existing lung conditions, and had more invasive therapies will likely be at higher risk for long term lung disease or damage due to COVID, there remains a risk to healthy athletes. Due to the wide-spread nature of COVID, some athletes who contract COVID will likely have a prolonged pulmonary recovery and less commonly some may have a life long chronic lung disease caused by COVID.
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Stay tuned for the highly anticipated next post on heart-related manifestations of COVID and the athlete. There will still be several more posts on COVID and after that I plan to get into some other sports medicine topics. One that I’ve been thinking about recently is retention of youth athletes and how we can keep our youth active.
Nonmedical followers
https://www.bbc.com/news/health-53065340
Medical Followers:
Long term respiratory complications of covid-19
Pulmonary fibrosis secondary to COVID-19: a call to arms?
COVID-19 and risk of pulmonary fibrosis: the importance of planning ahead