Long COVID can cause more than 200 different symptoms affecting nearly every organ system in the body. The most common are persistent fatigue, difficulty concentrating, shortness of breath, and sleep problems, but the condition can also trigger heart-related symptoms, digestive issues, mood changes, and problems with smell or taste. Roughly 29% of people in the U.S. who’ve had COVID-19 have experienced long COVID symptoms at some point during their recovery.
The Most Common Symptoms
The CDC identifies 34 frequently reported long COVID symptoms. The ones that show up most often in clinical studies are fatigue (reported by up to 93% of symptomatic patients), shortness of breath (around 70%), palpitations (60%), chest pressure (59%), joint pain (53%), concentration difficulties (48%), headache (47%), dizziness (46%), and memory loss (45%). Many people experience several of these simultaneously rather than just one or two.
Other commonly reported symptoms include bloating, constipation, or diarrhea; persistent cough; changes in smell or taste; recurring headaches; and sleep disturbances. Symptoms don’t always appear right after the initial infection. They can emerge weeks later, come and go unpredictably, or shift in character over time.
Brain Fog and Cognitive Slowing
Cognitive symptoms are among the most disruptive features of long COVID. The umbrella term “brain fog” captures what many patients describe: trouble concentrating, difficulty finding words, slower thinking, and unreliable short-term memory. These aren’t subtle complaints. A multicenter study published in The Lancet found that people with long COVID responded to cognitive tasks roughly three standard deviations slower than healthy controls, a dramatic gap. Over half of long COVID patients in that study showed processing speeds that fell far outside the normal range.
Nearly 70% of long COVID patients in the study reported concentration difficulty. The researchers also found that these cognitive deficits couldn’t be explained by fatigue, depression, anxiety, or poor sleep alone. Something about the condition itself appears to impair the brain’s processing speed independently of other symptoms. Structural and functional brain changes have been documented in long COVID patients, though the exact mechanisms are still being investigated.
Heart and Circulatory Symptoms
Palpitations, chest pressure, chest pain, and a racing heart rate are all common in long COVID. One significant driver of these symptoms is a condition called POTS (postural orthostatic tachycardia syndrome), where your heart rate spikes abnormally when you stand up. In a study of 467 highly symptomatic long COVID patients, 31% met the diagnostic criteria for POTS. The condition is diagnosed when your heart rate jumps by at least 30 beats per minute upon standing, without a corresponding drop in blood pressure.
Palpitations affected about 75% of long COVID patients with POTS, compared to 45% of those without any signs of the condition. Despite how alarming these symptoms feel, the same study found no cases of dangerous heart rhythms like atrial fibrillation or ventricular tachycardia on extended heart monitoring. Still, the elevated heart rate during everyday activities like walking or standing can be exhausting and limits what people can do physically.
Depression and Anxiety
Long COVID carries a significant mental health burden that persists for years. At three years after infection, about 17% of adults with long COVID reported depressive symptoms, compared to 7.5% of those who recovered without long-term issues. Anxiety followed a similar pattern: 17.2% of long COVID patients versus 9.3% of those without. Overall, people with long COVID had an 86% higher risk of depression and a 60% higher risk of anxiety three years out.
Depression risk actually increased over time rather than fading, with the strongest association appearing at later follow-up points. Anxiety, by contrast, remained elevated throughout the entire follow-up period. These aren’t simply reactions to being sick for a long time. The biological disruptions caused by the virus, including immune dysregulation, nervous system dysfunction, and possible viral persistence in tissues, likely contribute directly to mood changes.
What’s Happening in the Body
Several biological processes appear to drive long COVID symptoms, often in combination. Fragments of the virus or even replicating virus may persist in tissues long after the initial infection clears. The immune system can remain in an activated, inflammatory state, with primed immune cells continuing to cause damage. In some people, the infection reactivates dormant viruses already in the body, like Epstein-Barr virus, adding another layer of symptoms.
Other mechanisms include abnormal blood clotting and circulation problems at the micro level, dysfunction in the vagus nerve (which controls heart rate, digestion, and other automatic body functions), autoimmune reactions where the immune system mistakenly attacks the body’s own tissues, and disruptions to the gut microbiome. This wide range of underlying causes helps explain why long COVID looks so different from person to person and why it affects so many organ systems at once.
How Long Symptoms Last
Long COVID is defined as symptoms persisting beyond the acute phase of infection, typically four weeks or more. Most people see significant improvement after three months. Others don’t improve for many months or even years. Symptoms can resolve and then return, or new symptoms can appear after earlier ones fade. This unpredictable, relapsing pattern is one of the most frustrating aspects of the condition for patients.
There is no lab test that can confirm or rule out long COVID. Doctors diagnose it based on your history of COVID-19 infection (confirmed or probable) and your ongoing symptoms. A positive test result from your original infection isn’t required for diagnosis.
Long COVID in Children
Children can develop long COVID, though it appears less common than in adults. In 2022, about 1.3% of U.S. children had experienced long COVID at some point, with 0.5% actively experiencing symptoms at the time they were surveyed. Teenagers ages 12 to 17 were roughly twice as likely as younger children to develop the condition. Girls were more likely than boys to be affected (1.6% versus 0.9%).
Who’s at Higher Risk
Your risk of severe COVID-19, and by extension long COVID, rises with age and the number of underlying health conditions you have. People with compromised immune systems face particular vulnerability, as vaccines may not provide full protection. Racial and ethnic minority groups and people with disabilities also face elevated risk, partly due to differences in healthcare access and occupational exposure. Having multiple chronic conditions compounds risk in a cumulative way rather than each condition adding risk independently.