Dyspnea, the medical term for shortness of breath, is the unsettling sensation of not being able to take a full breath. It is a feeling of air hunger or difficulty breathing that can occur during activity or while resting. Shortness of breath is a recognized symptom of SARS-CoV-2 infection, and its presence can signal that the infection is affecting the lower respiratory tract.
Shortness of Breath in COVID-19: Prevalence and Context
Shortness of breath is a primary symptom of COVID-19, often appearing alongside fever and cough. The probability of experiencing dyspnea varies widely, with reported prevalence ranging from approximately 18.6% to nearly 60% in the general infected population.
This symptom is not always an early sign; it often develops several days after initial symptoms like fever or sore throat begin. The frequency and severity of breathlessness depend on factors such as vaccination status and the specific viral variant. Earlier strains, such as Alpha or Delta, were more often linked to severe breathlessness compared to later variants.
The presence of shortness of breath strongly correlates with disease severity. It becomes significantly more common in cases requiring hospitalization, particularly for patients admitted to intensive care. While it can appear in milder cases, the worsening of breathlessness indicates the infection is progressing toward a more serious stage.
How the Virus Affects the Respiratory System
The respiratory distress caused by COVID-19 begins when the SARS-CoV-2 virus infects the cells lining the airways and the tiny air sacs in the lungs called alveoli. These alveoli are where oxygen normally crosses into the bloodstream and carbon dioxide is removed. The virus binds to the ACE2 receptors found on these cells, initiating inflammation.
The body’s vigorous immune response can lead to damage of the delicate alveolar-capillary barrier. This damage causes fluid to leak into the alveoli, which impairs the lung’s ability to transfer oxygen efficiently into the blood. The resulting condition is COVID-19 pneumonia, causing the lungs to become stiff and less efficient.
In severe cases, this lung injury can progress to Acute Respiratory Distress Syndrome (ARDS), where the lungs cannot provide enough oxygen. The infection can also activate the coagulation cascade, leading to the formation of small blood clots within the lung’s microvasculature. This clotting disrupts blood flow and contributes to a poor match between ventilation and perfusion, ultimately leading to lower oxygen levels and breathlessness.
Emergency Warning Signs and When to Seek Help
While mild breathlessness may be managed at home, it is important to recognize specific signs that indicate a medical emergency. Any sudden worsening of breathing difficulty requires immediate attention and should prompt an immediate call to emergency services.
Critical Warning Signs
The most significant red flag is severe trouble breathing, which may manifest as gasping or straining for air even while at rest. Persistent pain or pressure felt in the chest area is also a serious symptom that signals the need for urgent medical help.
Other neurological signs, such as new confusion or the inability to wake up or stay awake, are indicators of critically low oxygen levels affecting the brain. A visible change in skin color, known as cyanosis, is a late-stage warning sign of severe oxygen deprivation. This may appear as a pale, gray, or bluish tint to the lips, nail beds, or face.
If any of these emergency signs are observed, call 911 or your local emergency number immediately.