Low body temperature, medically termed hypothermia, is defined as a core body temperature falling below 35.0 °C (95.0 °F). While many infectious diseases, including COVID-19, are commonly associated with fever—an elevated body temperature—the presence of hypothermia in individuals with SARS-CoV-2 infection has emerged as a notable and less anticipated clinical finding.
Normal Body Temperature and Hypothermia
The human body maintains a remarkably stable internal temperature, typically around 36.5–37.5 °C (97.7–99.5 °F), through a process called thermoregulation. This intricate system, primarily governed by the hypothalamus in the brain, constantly balances heat production and heat loss. When the body encounters cold, the hypothalamus triggers mechanisms like shivering to generate heat and constricts blood vessels in the skin to reduce heat loss. Conversely, sweating and increased blood flow to the skin help dissipate excess heat.
This condition can range in severity, from mild to severe, which can be life-threatening. While often linked to cold environmental exposure, hypothermia can also result from conditions that impair the body’s heat production or increase heat loss, such as certain medical conditions, medications, or extreme age.
Occurrence of Low Body Temperature in COVID-19
While fever is a widely recognized and common symptom of COVID-19, occurring in a significant percentage of adults, low body temperature, or hypothermia, has also been observed in infected individuals, though it is considerably less common.
The presence of hypothermia in COVID-19 patients appears particularly relevant in more severe disease presentations. Research indicates that an abnormally low body temperature may serve as an indicator of a more serious condition and has been associated with poorer patient outcomes. For example, one study highlighted that individuals with a core body temperature below 36°C (96.8°F) experienced higher rates of mortality.
This temperature dysregulation underscores how SARS-CoV-2 can impact the body’s internal systems. While the immune system commonly mounts a fever to combat pathogens, the occurrence of hypothermia suggests a profound disruption in the body’s ability to maintain its thermal balance in certain patients.
How COVID-19 Can Cause Low Body Temperature
COVID-19 can lead to low body temperature through various mechanisms, involving the virus’s direct effects and the host’s immune response. One proposed pathway involves the SARS-CoV-2 virus potentially affecting the central nervous system, specifically the hypothalamus. The hypothalamus is the brain region responsible for regulating body temperature. The virus may directly invade the brain or induce reactive inflammation that disrupts the hypothalamus’s normal function, thereby impairing thermoregulation.
Systemic inflammation, a hallmark of severe COVID-19, can also contribute to hypothermia. The intense release of inflammatory molecules, known as cytokines, can lead to a “cytokine storm.” While cytokines often induce fever, in severe cases, this overwhelming inflammatory response can paradoxically lead to a decrease in body temperature, potentially by overwhelming the body’s thermoregulatory capacity or by shifting metabolic processes.
Furthermore, severe infections can lead to conditions like sepsis, a life-threatening response to infection that can significantly disrupt the body’s ability to maintain temperature. Sepsis-induced hypothermia is a known phenomenon where the body’s metabolic rate drops, and heat production is impaired, contributing to a lower core temperature. Organ dysfunction, prevalent in severe COVID-19, can further exacerbate this. For example, impaired liver or kidney function can affect metabolic processes crucial for heat generation.
Metabolic derangements, such as severe electrolyte imbalances or hypoglycemia, commonly seen in critically ill patients, can also impede the body’s ability to produce sufficient heat. Certain medications administered during COVID-19 treatment, particularly those used in intensive care settings, may also have side effects that contribute to a reduction in body temperature. These factors can collectively result in hypothermia in vulnerable individuals with COVID-19.
Implications and Care for Low Body Temperature in COVID-19
The presence of low body temperature in COVID-19 patients carries significant clinical implications, often signaling increased disease severity. Unlike fever, which is typically a sign of the body’s active immune response, hypothermia in the context of infection can indicate a failure of the body’s compensatory mechanisms or an overwhelming physiological insult. Studies have consistently linked hypothermia in COVID-19 to higher mortality rates and a more severe disease course, suggesting it can be a marker for critical illness.
Recognizing hypothermia in COVID-19 is important for timely medical intervention. Symptoms of hypothermia can include confusion, drowsiness, shivering (though it may stop in severe cases), slow breathing, and a weak pulse. For anyone with COVID-19 experiencing a body temperature below 35°C (95°F), immediate medical consultation is advised.
General care for low body temperature involves careful rewarming and supportive measures. Medical professionals typically focus on gradually raising the core body temperature. This can involve moving the individual to a warmer environment, removing wet clothing, and applying warm, dry compresses to the central areas of the body, such as the neck, chest, and groin. Warm, non-alcoholic fluids may also be offered if the patient is conscious and able to drink.
Rapid rewarming methods, such as very hot baths or heating lamps, are generally avoided to prevent complications like sudden drops in blood pressure or cardiac stress. The primary goal is to stabilize the patient while addressing the underlying COVID-19 infection and any contributing factors to the hypothermia. This approach aims to mitigate risks associated with low body temperature.