Postural Orthostatic Tachycardia Syndrome (POTS) is a complex disorder characterized by an abnormal increase in heart rate that occurs upon standing up from a lying down position. This condition is a form of dysautonomia, meaning it involves a malfunction of the Autonomic Nervous System (ANS). People with POTS frequently experience symptoms like dizziness, fatigue, and palpitations, but they also report significant issues with temperature regulation. This often leads to the question of whether the disorder itself can trigger a true fever or simply creates the uncomfortable sensation of being overheated. Understanding the role of the ANS in temperature control is the first step in clarifying this common concern.
The Role of the Autonomic Nervous System in Thermoregulation
The Autonomic Nervous System acts as the body’s internal thermostat, continuously working to maintain a stable core temperature through a process called thermoregulation. This system manages heat loss or conservation by controlling processes such as shivering and sweating. A primary mechanism involves regulating the diameter of blood vessels near the skin’s surface.
When the body needs to cool down, the ANS triggers vasodilation, which is the widening of blood vessels. This allows more warm blood to flow closer to the skin, where heat can dissipate into the environment. Conversely, when the body needs to conserve heat, the ANS causes vasoconstriction, or the narrowing of these vessels, reducing blood flow to the skin.
In POTS, the malfunctioning ANS struggles to coordinate these vascular responses effectively. Heat causes excessive vasodilation, leading to an increased pooling of blood in the lower extremities. This pooling reduces the amount of blood returning to the heart and brain, compelling the heart to beat faster to compensate. The resulting instability makes it difficult to regulate heat dissipation, which is why individuals with POTS often experience severe heat intolerance.
Does POTS Cause a True Fever?
POTS does not typically cause a sustained, clinically defined fever, but it does cause significant temperature dysregulation and the subjective feeling of being hot. A true fever is medically defined as an oral temperature of 100.4°F (38°C) or higher, and it is usually a sign of an infection or inflammatory process. The feeling of being hot experienced in a POTS flare is instead a result of the poor circulation and inadequate blood flow regulation due to the ANS dysfunction.
Some individuals with dysautonomia may experience temporary, low-grade temperature instability, sometimes ranging between 99.5°F and 100.3°F. This slight elevation is distinct from a true fever, and it is often a manifestation of the body’s faulty thermoregulatory control rather than a response to a pathogen. The confusion arises because the symptoms of this dysregulation, such as flushing and sweating, mimic the body’s natural response to an elevated temperature.
If a person with POTS measures a temperature above the 100.4°F threshold, it is highly likely that a co-existing illness, such as a viral or bacterial infection, is the cause. A true fever will significantly worsen POTS symptoms because the body’s natural response to infection is to increase heart rate by approximately 8 to 10 beats per minute for every degree of temperature elevation. This strain on the cardiovascular system can lead to more pronounced lightheadedness and fatigue.
Temperature Management and Warning Signs
Managing temperature is an important part of controlling POTS symptoms, especially since heat is a common trigger for symptom flares. Proactive strategies for coping with heat intolerance include ensuring consistent hydration with water and electrolyte-rich beverages to maintain blood volume. Using external cooling methods is also highly recommended, such as wearing cooling vests, applying cold packs, or using handheld fans to assist the body’s inefficient heat-dissipation processes.
It is also beneficial to avoid sudden shifts in temperature, as rapid changes can shock the sensitive autonomic system. Gradually adjusting to air-conditioned environments after being outside in the heat is better than an immediate drastic change. Wearing layers allows for easy adjustment to different indoor and outdoor temperatures throughout the day.
A true fever requires medical attention, especially for people with POTS. Contact a healthcare provider if your temperature reaches 100.4°F (38°C) or higher and is sustained. Seek immediate medical attention if a fever is accompanied by severe symptoms like chest pain, mental confusion, or difficulty breathing.