A hot flash is the sudden, intense sensation of heat and sweating, commonly associated with hormonal changes like menopause. People contracting COVID-19 often experience dramatic temperature fluctuations, leading to confusion about whether the virus triggers true hot flashes. While rapidly alternating between being chilled and overheating is a recognized COVID-19 symptom, the underlying mechanism is distinct from a classic hormonal hot flash. This temperature dysregulation results directly from the body’s infectious response to the SARS-CoV-2 virus.
Distinguishing Fever and Temperature Swings
A true fever is the body’s coordinated response to infection, where the thermal set point in the hypothalamus is deliberately raised. This elevation is triggered by immune signaling molecules, forcing the body to conserve heat, often causing chills and shivering. Once the immune system begins to win the fight or medication is introduced, the hypothalamic set point returns to normal, prompting the body to release excess heat through vasodilation and sweating, which feels like a sudden, intense hot flush.
In contrast, a classic hormonal hot flash, known as a vasomotor symptom, is a sudden, transient event that does not involve a sustained elevation in core body temperature. It relates to estrogen fluctuations, which narrow the thermoneutral zone—the comfortable temperature range the body can tolerate without sweating or shivering. When the body crosses this narrow threshold, the hypothalamus overreacts, causing a rapid flush of heat and sweating outside of a fever cycle. The dramatic temperature swings experienced during acute COVID-19 are primarily part of the infectious fever cycle, even though they mimic the physical sensation of a hormonal hot flash.
The Inflammatory Response Behind Temperature Changes
The mechanism behind COVID-related temperature swings traces back to the systemic inflammatory response triggered by the infection. When the SARS-CoV-2 virus enters the body, the immune system releases pro-inflammatory signaling proteins, known as cytokines, to coordinate the defense. Cytokines like Interleukin-6 (IL-6) act as pyrogens, directly influencing the body’s thermoregulatory center.
These pyrogenic cytokines travel to the hypothalamus, the brain region controlling body temperature, and “reset” its thermostat to a higher setting. This resetting is the biological trigger for the fever, intended to create an inhospitable environment for the virus. The subsequent rapid shifts from high heat to drenching sweats occur when inflammatory signaling drops, causing the body to swiftly dump the excess heat.
Research suggests the virus may directly affect the nervous system, contributing to persistent temperature dysregulation. The hypothalamus is rich in ACE-2 receptors, which the virus uses to enter cells, making it a potential target for damage. This impact on the brain’s temperature control center may explain why some individuals experience lingering temperature instability long after the acute infection has passed. This prolonged dysregulation is a sign of a compromised homeostatic system, often seen in cases of Long COVID.
Symptom Duration and Relief Strategies
For most individuals with acute COVID-19, pronounced temperature swings and fever typically subside within the first week of infection. Symptom resolution aligns with the body clearing the initial viral load and the subsequent reduction in inflammatory cytokine levels. However, temperature instability, including sudden hot or cold flashes, can persist for weeks or months as part of the post-viral syndrome known as Long COVID.
Managing acute temperature fluctuations focuses on comfort and preventing dehydration. Wear layered clothing that can be easily removed when a hot flush hits and replaced when chills return. Maintaining consistent hydration with water or electrolyte solutions is important, as heavy sweating can quickly deplete the body’s fluid reserves.
Over-the-counter fever reducers, such as acetaminophen or ibuprofen, help stabilize body temperature by interfering with the cytokine signaling pathway in the hypothalamus. These medications lower the set point, reducing the intensity of the fever and subsequent temperature swings. Cool compresses applied to the forehead or neck provide immediate, localized relief during intense heat. If temperature dysregulation is severe, persistent, or accompanied by other debilitating symptoms, consult a healthcare professional to rule out other causes and discuss management strategies for potential Long COVID.