Postural Orthostatic Tachycardia Syndrome (POTS) is a chronic condition affecting the autonomic nervous system (ANS), which controls involuntary functions like heart rate, blood pressure, and digestion. It causes an abnormal increase in heart rate upon standing, leading to various symptoms that can impact daily life. A link between POTS and COVID-19, particularly “long COVID” where symptoms persist for weeks or months, has been increasingly recognized. This article explores POTS, its connection with COVID-19, post-COVID diagnosis, and management strategies.
Understanding POTS
POTS is a form of dysautonomia, a disorder where the autonomic nervous system (ANS) does not function properly. The ANS manages bodily functions that occur without conscious thought, including heart rate, blood pressure, sweating, and body temperature. In individuals with POTS, the ANS malfunctions in regulating blood flow when changing from a lying or sitting position to an upright one. This often results in blood pooling in the lower extremities, reducing blood return to the heart and brain.
To compensate, the heart rate increases by at least 30 beats per minute (bpm) in adults, or 40 bpm in adolescents, within 10 minutes of standing. This abnormal heart rate response, without a significant drop in blood pressure, is a hallmark of POTS. Common symptoms include dizziness, lightheadedness, fatigue, brain fog (difficulty focusing or remembering), and heart palpitations. Other symptoms include headaches, nausea, and shakiness, which worsen with prolonged standing and improve when lying down.
The Connection Between COVID-19 and POTS
An increase in POTS diagnoses following COVID-19 infections has brought attention to this condition as a component of “long COVID.” Studies indicate that 2% to 14% of COVID-19 survivors may develop POTS, with 9% to 61% experiencing POTS-like symptoms within six to eight months post-infection.
One proposed mechanism linking COVID-19 to POTS is direct or indirect disruption of the autonomic nervous system. The SARS-CoV-2 virus can invade the nervous system, potentially leading to injury to autonomic nerve fibers.
Another theory involves an autoimmune response, where the immune system mistakenly attacks healthy tissues, including those involved in ANS regulation. COVID-19 can trigger autoantibodies that interfere with autonomic function, leading to POTS symptoms.
Viral persistence, where remnants of the virus or ongoing inflammation remain in the body, is also a factor. This prolonged presence can contribute to sustained immune activation and autonomic dysregulation. Microvascular damage, or harm to small blood vessels, might also occur, impairing blood flow regulation and exacerbating POTS symptoms.
Recognizing and Diagnosing POTS Post-COVID
Individuals who develop POTS following a COVID-19 infection experience symptoms that worsen when upright. Beyond typical POTS symptoms like dizziness, lightheadedness, and a racing heart, post-COVID patients report fatigue, exercise intolerance, and shortness of breath. Chest discomfort and gastrointestinal issues such as bloating and nausea are also reported. Cognitive difficulties, or “brain fog,” including trouble concentrating or remembering, are prominent.
Diagnosis for POTS post-COVID begins with a medical evaluation and detailed symptom history. A diagnostic criterion is a sustained increase in heart rate of at least 30 bpm in adults (or 40 bpm in adolescents) within 10 minutes of standing, without a significant drop in blood pressure. Healthcare providers use tests such as the active stand test or the tilt-table test.
During an active stand test, heart rate and blood pressure are measured as the patient transitions from lying down to standing. The tilt-table test involves securing the patient to a table that is then tilted upright while continuously monitoring heart rate and blood pressure. This test helps observe the body’s response to posture changes. Other conditions that might cause similar symptoms, such as anemia, thyroid disorders, or dehydration, must be ruled out through blood tests to ensure an accurate POTS diagnosis.
Management Strategies for POTS
Managing POTS symptoms involves lifestyle adjustments to improve blood volume and circulation. A primary recommendation is to increase fluid and salt intake, under medical guidance, to expand blood volume. Patients are advised to consume 2-3 liters of water per day and 3-10 grams of sodium, achievable through dietary salt, salt tablets, or electrolyte solutions. Drinking water rapidly before getting out of bed can also help prevent dizziness.
Graduated exercise programs are an important component of management, starting with recumbent exercises like swimming, rowing, or using a recumbent bike to minimize upright activity. As tolerance improves, patients can gradually progress to more upright activities, focusing on strengthening core and lower body muscles. Wearing compression garments, such as stockings or abdominal binders, helps prevent blood pooling in the lower body and improves circulation.
Managing fatigue and brain fog involves pacing activities and ensuring rest. Eating smaller, more frequent meals and limiting refined carbohydrates can help regulate blood flow after eating. Medications may be prescribed to regulate heart rate or blood pressure, or manage other symptoms. An interdisciplinary care team, including cardiologists, neurologists, and physical therapists experienced in POTS, can provide support.