“I just can’t do what I used to anymore.”
As pulmonologists and critical care doctors treating patients with lung disease, we have heard many of our patients recovering from COVID-19 tell us this even months after their initial diagnosis. Though they may have survived the most life-threatening phase of their illness, they have yet to return to their pre-COVID-19 baseline, struggling with activities ranging from strenuous exercise to doing laundry.
These lingering effects, called long COVID, have affected as many as 1 in 5 American adults diagnosed with COVID-19. Long COVID includes a wide range of symptoms such as brain fog, fatigue, cough and shortness of breath. These symptoms can result from damage to or malfunctioning of multiple organ systems, and understanding the causes of long COVID is a special research focus of the Biden-Harris administration.
Not all breathing problems are related to the lungs, but in many cases the lungs are affected. Looking at the lungs’ basic functions and how they can be affected by disease may help clarify what is on the horizon for some patients after a COVID-19 infection.
Normal lung function
The main function of the lungs is to bring oxygen-rich air into the body and expel carbon dioxide. When air flows into the lungs, it is brought into close proximity with the blood, where oxygen diffuses into the body and carbon dioxide diffuses out.