While fever is a widely recognized symptom of COVID-19, low body temperature is a less common but significant occurrence. Understanding this less typical presentation is important, as it can sometimes signal a more serious progression of the illness.
Is Low Body Temperature a COVID Symptom?
Low body temperature, or hypothermia, is indeed a documented symptom of COVID-19, though it is less common than a fever. Some studies indicate that a substantial number may not develop a fever at all, or may even present with a lower-than-normal body temperature. For instance, a study from April 2020 found that only about 55.5% of individuals with COVID-19 developed a fever, and a different study noted that only 30.7% of confirmed cases had a fever upon hospital admission. This suggests that a significant portion of patients may not exhibit the typical fever response.
Low body temperature, particularly below 95°F (35°C), can indicate a more severe infection. This is especially true for vulnerable populations, such as the very old or very young, malnourished individuals, or those with chronic illnesses or compromised immune systems. When the body struggles to mount an adequate immune response or experiences systemic stress, a drop in core temperature may occur, signaling a potentially poor outcome.
Why Body Temperature Fluctuates with COVID
The human body maintains a core temperature around 98.6°F (37°C) through thermoregulation, primarily controlled by the hypothalamus. When an infection like COVID-19 occurs, the immune system releases signaling molecules such as cytokines, which trigger a fever by resetting the body’s temperature set point higher. This elevated temperature helps the body fight off pathogens.
However, in some cases of COVID-19, particularly severe infections, this thermoregulation can become dysregulated, leading to a drop in body temperature instead of a rise. One hypothesis suggests that the SARS-CoV-2 virus may directly affect the central nervous system, potentially entering the brain through the olfactory tracts and disrupting the hypothalamus. This disruption could impact the warm-sensitive neurons in the medial preoptic area, leading to hypothermia.
Additionally, an overwhelming immune response, similar to a sepsis-like state, can lead to hypothermia even with elevated inflammatory markers. Factors such as metabolic changes, severe energy depletion, or organ dysfunction can also contribute to a decrease in body temperature. This suggests that hypothermia in COVID-19 can be a sign of the body struggling under severe illness, rather than actively fighting the infection with a fever.
Recognizing Serious Symptoms and When to Get Help
A concerning low body temperature is defined as below 95°F (35°C). If your temperature drops to this level or lower while you have COVID-19, it warrants immediate medical attention. Hypothermia can manifest with symptoms including:
Chills
Shivering
Confusion
Slurred speech
Drowsiness
Cold, pale skin
Slow heart rate
Slow breathing
General weakness
Sleepiness
These signs, especially when accompanied by a low body temperature, can indicate a critical illness and should not be ignored. Other serious symptoms that require emergency care include:
Trouble breathing
Persistent pain or pressure in the chest
New confusion
Inability to wake or stay awake
Pale, gray, or blue-colored skin, lips, or nail beds
If you observe any of these emergency warning signs, call 911 or seek immediate medical help at your local emergency facility. Inform the operator that you are seeking care for someone who has or may have COVID-19.