Excessive perspiration, often manifesting as drenching night sweats, is a frequent concern for individuals with a COVID-19 infection. While fever and respiratory issues are widely recognized, many patients report a surprising change in their body’s temperature regulation. Understanding the relationship between SARS-CoV-2 infection and altered sweating patterns requires examining both the acute illness phase and the longer-term effects on the nervous system.
Sweating During Acute Infection
Excessive perspiration, clinically known as hyperhidrosis, is a recognized feature of the acute phase of COVID-19 infection. This symptom is frequently noted as nocturnal hyperhidrosis, or “night sweats,” where the person wakes up to find their bedding soaked. This heavy sweating often presents alongside typical systemic symptoms, including fever, chills, and muscle aches. For most patients, this acute sweating resolves as the initial infection clears, usually within the first week or two.
The Immune System’s Role in Thermoregulation
The underlying mechanism for sweating during the acute phase is rooted in the body’s inflammatory response to the viral presence. Immune cells release signaling molecules called pyrogens and pro-inflammatory cytokines, such as Interleukin-6 (IL-6). These messengers travel to the hypothalamus, the brain region controlling body temperature, resetting the body’s internal thermostat to a higher point. This elevated set point initiates a fever, causing the body to generate heat through mechanisms like shivering.
Once the immune system gains control, inflammatory cytokine levels drop, and the hypothalamic set point returns to normal. The body recognizes that it is overheated relative to the new, lower set point. To shed this excess heat, the body initiates the cooling process, known as defervescence or diaphoresis. This rapid temperature reduction is accomplished through profuse sweating, which is a sign that the body is successfully breaking the fever.
Persistent Sweating After Recovery
For some individuals, excessive or inappropriate sweating can persist long after the virus has been cleared, a phenomenon linked to Long COVID. This lingering symptom is often attributed to a disruption in the autonomic nervous system (ANS), a condition referred to as dysautonomia. The ANS controls involuntary functions, including heart rate, blood pressure, and temperature regulation, which governs sweating.
The sustained inflammatory state appears to impair the function of the sympathetic nervous system, leading to unpredictable hyperhidrosis unrelated to heat or exercise. Changes in sweating patterns are often observed alongside other signs of dysautonomia, such as lightheadedness, heart palpitations, or dizziness upon standing (POTS). This persistent sweating can involve both eccrine glands (watery sweat) and apocrine glands (thicker fluid).
The sustained presence of inflammatory markers, like elevated Interleukin-17 (IL-17), has been observed in some Long COVID patients. This suggests a persistent immune-mediated alteration that may contribute to thermal dysregulation.
Signs That Require Medical Attention
While sweating during an infection is common, certain circumstances warrant a medical evaluation to rule out other serious conditions. Excessive sweating, whether acute or persistent, requires immediate attention if accompanied by chest pain, significant shortness of breath, or severe pressure in the chest. These symptoms could indicate a serious respiratory or cardiovascular complication.
A healthcare provider should also be consulted if the sweating is accompanied by:
- Unexplained weight loss.
- A persistent cough that does not resolve.
- A fever that lasts for several days.
- New onset of nocturnal hyperhidrosis that consistently disrupts sleep or soaks clothing, especially if it continues for more than a few weeks after recovery.
Consultation ensures the sweating is not a sign of an unrelated medical issue or persistent dysautonomia.