The term “hot flash” is generally understood as a sudden, intense feeling of heat, often accompanied by flushing and profuse sweating, typically associated with hormonal changes. Individuals who have experienced COVID-19 frequently report similar, abrupt temperature swings. These episodes feel like hot flashes, raising questions about a connection between the viral infection and the body’s thermoregulation. This article explores the relationship between SARS-CoV-2 infection and these temperature dysregulations, examining the acute symptoms and the biological reasons for their occurrence.
Temperature Swings During Acute Infection
Many individuals with an active COVID-19 infection experience sudden, dramatic temperature fluctuations that strongly resemble a hot flash. These episodes often present as a rapid onset of intense internal heat, followed quickly by drenching sweats and sometimes a subsequent chill. This symptom is distinct from a typical fever, which involves a sustained elevation of the body’s temperature set point.
These temperature swings often manifest as night sweats, a recognized symptom of the acute infection. The hyperhidrosis, or excessive sweating, associated with these episodes can disrupt sleep and daily activity. While symptoms like cough and fatigue are more commonly reported, these sudden thermal events are a distinct feature of the body’s reaction to the virus. They represent an instability in the body’s ability to maintain a steady internal temperature, even when the measured core temperature is not severely elevated.
Why COVID Affects Body Temperature Regulation
The mechanism behind these sudden thermal shifts is rooted in the body’s inflammatory response to the SARS-CoV-2 virus, and it differs significantly from hormonal causes. When the body detects the virus, the immune system releases pro-inflammatory cytokines, such as Interleukin-1 beta (IL-1 beta) and Tumor Necrosis Factor-alpha (TNF-alpha). These molecules act as pyrogens, which are substances that cause fever.
These inflammatory pyrogens directly affect the hypothalamus, a powerful region in the brain that functions as the body’s thermoregulatory thermostat. Normally, the hypothalamus maintains the body’s core temperature within a narrow range, but the presence of these cytokines disrupts its function. This disruption causes the hypothalamic set point to become unstable, leading to sudden, uncontrolled shifts in perceived temperature and physical responses like sweating and flushing.
In a normal fever, the hypothalamus raises the set point, and the body works to reach that higher temperature. In contrast, the COVID-related temperature dysregulation involves a fluctuating or temporarily compromised set point. This causes the body to erratically initiate cooling mechanisms like sweating, even when the temperature is not consistently high. The virus itself may also be capable of neuroinvasion, directly affecting these regulatory centers within the brain.
Lingering Temperature Issues After Recovery
For a substantial number of people, the temperature instability does not resolve immediately after the acute infection passes. This becomes a feature of Post-Acute Sequelae of SARS-CoV-2 infection, commonly known as Long COVID or PASC. Persistent temperature dysregulation, including recurrent hot flashes, night sweats, and heat intolerance, is a recognized symptom in the months following the initial illness.
This prolonged instability is frequently attributed to autonomic nervous system (ANS) dysfunction, or dysautonomia. The ANS regulates involuntary processes like heart rate, blood pressure, digestion, and temperature control. It is hypothesized that the initial viral infection or the resulting inflammatory response may dysregulate parts of the ANS, including the pathways that signal the hypothalamus.
Specific manifestations of this dysautonomia include hyperhidrosis (excessive sweating) and heat intolerance, which resemble persistent hot flashes. In some cases, this leads to Postural Orthostatic Tachycardia Syndrome (POTS), a type of dysautonomia characterized by an abnormal increase in heart rate upon standing. If these temperature-related symptoms persist for weeks or months after recovery, especially if they interfere with daily life, seeking medical consultation is warranted to explore the possibility of PASC.