The experience of an infection often involves a fever, the body’s natural response to raise its internal temperature set point to fight off a pathogen. Following a COVID-19 infection, however, some individuals notice a sustained shift in the opposite direction, reporting a persistently lower-than-usual body temperature. This perplexing temperature dysregulation can leave people feeling chilled and struggling to maintain a comfortable internal warmth. Understanding this deviation helps explain why the body’s internal thermal controls may be struggling to reset after the acute phase of the illness.
Is Low Body Temperature a Recognized Post-COVID Symptom
Persistent changes in body temperature below the typical 98.6°F (37°C) average have been documented in people recovering from COVID-19. For some, this manifests as a reduced basal body temperature, which may settle below 97.7°F (36.5°C) for extended periods after the infection has cleared. Temperatures that consistently remain below 96.8°F (36°C) are considered significantly low and indicate a definite change in the body’s thermal state. While less common than the lingering fevers reported by some patients, episodes of hypothermia, defined as a core body temperature below 95°F (35°C), have also been recorded in the post-acute phase of recovery, though this is rare and a serious medical event. This phenomenon confirms that temperature instability is a real post-infectious concern.
How COVID-19 Affects the Body’s Thermostat
The body’s temperature control center resides within the hypothalamus, a small structure deep inside the brain that acts like a thermostat. This region regulates numerous involuntary processes, including appetite, sleep, and the maintenance of body temperature. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or the subsequent inflammatory response appears capable of disrupting normal hypothalamic function.
The virus can potentially enter the central nervous system, either directly or indirectly, leading to neuroinflammation that disturbs the delicate balance of this control center. This inflammation can cause the hypothalamus to persistently lower its thermal set point, essentially telling the body that a lower temperature is the new normal. Furthermore, the body’s immune reaction releases signaling proteins called cytokines, which are meant to coordinate the fight against the infection. These cytokines can interfere with the signaling pathways within the brain that govern thermoregulation, leading to a long-term state of dysregulation.
The resulting hypothalamic dysfunction means the body loses its ability to accurately perceive and maintain its core temperature within the narrow, comfortable range. This disruption can also be linked to microcirculatory issues, where small blood vessels in the skin, which normally help regulate heat loss, become impaired. The combination of central regulatory failure and peripheral circulatory problems creates the persistent sensation of coldness or the inability to generate sufficient warmth.
Related Signs of Autonomic Nervous System Dysfunction
The body’s temperature control is managed by the autonomic nervous system (ANS), the involuntary system that governs functions like heart rate, breathing, and blood pressure. Since thermoregulation is an ANS function, a persistent low body temperature is often a sign of a broader condition known as dysautonomia, which is frequently observed in individuals with Post-Acute Sequelae of COVID-19 (PASC). This systemic issue affects the ANS’s ability to maintain homeostasis, or internal stability, across multiple systems.
People experiencing this thermal instability frequently report a constellation of other ANS-related symptoms. Orthostatic intolerance, for example, involves dizziness or lightheadedness that worsens upon standing or maintaining an upright posture, often associated with conditions like Postural Orthostatic Tachycardia Syndrome (POTS). These episodes are caused by the ANS failing to properly constrict blood vessels, leading to a drop in blood pressure and reduced blood flow to the brain when standing.
Other signs of dysautonomia include chronic fatigue not relieved by rest, erratic heart rates or palpitations, and cognitive impairment, often described as “brain fog.” The low body temperature is a single symptom within a larger pattern of systemic dysfunction. The involvement of the ANS explains why temperature regulation is compromised alongside issues like heart rate variability and blood pressure control.
When to Seek Medical Guidance
Monitoring baseline temperature changes is a practical first step for anyone concerned about persistent thermal shifts after a COVID-19 infection. It is helpful to track your temperature at the same time each day using a reliable thermometer to establish your individual baseline. Note any changes that consistently fall below your pre-illness average or below the 97°F mark.
Seek consultation with a healthcare provider to discuss a persistently low temperature, especially when accompanied by other signs of ANS involvement, such as severe fatigue, chronic dizziness, or rapid heart rate changes. A medical professional can assess whether the temperature drop is part of a systemic dysautonomia or another underlying issue. Immediate medical attention is necessary if your temperature drops below 95°F (35°C), as this level of hypothermia can lead to severe confusion, slurred speech, or loss of consciousness.