Does inflammation affect body temperature? The surprising connection

September 27, 2025 •

5 min read

Over the last century, scientific understanding of the immune system has revealed a critical link between the body's natural defense mechanisms and thermoregulation. It is now well-established that the body's inflammatory response can significantly affect body temperature, leading to both fever and, in severe cases, hypothermia.

Quick Summary

Inflammation, the body's protective response to injury or infection, directly impacts body temperature by releasing chemical signals called cytokines that reset the brain's thermostat, most often causing a fever. However, in severe systemic inflammation like sepsis, this response can be overwhelmed, resulting in a dangerous drop in core temperature known as hypothermia. The specific effect depends on the intensity and duration of the inflammatory process.

Key Points

Fever is a common result: Acute inflammation, typically from an infection, triggers the release of pyrogenic cytokines, which act on the brain to raise the body's temperature set point and cause a fever.
Hypothermia can also occur: In severe systemic inflammation, such as sepsis, the immune response can become dysregulated, leading to a dangerous and life-threatening drop in core body temperature (hypothermia).
Chronic inflammation can cause persistent low-grade fever: Conditions like autoimmune diseases or cancer, which involve chronic inflammation, may cause persistent low-grade fevers that signal ongoing inflammatory activity in the body.
Localized heat is a classic sign: The 'heat' sign of local inflammation is caused by increased blood flow to an injured or infected area, distinct from a systemic fever.
Temperature affects immune cell activity: Research shows that temperature changes, like those during fever, can influence the activity and function of immune cells, demonstrating a two-way relationship between temperature and immunity.
Thermography can detect temperature changes: Non-invasive infrared thermography can be used to detect and quantify localized inflammatory heat patterns, aiding in the diagnosis and monitoring of conditions like arthritis.

The Connection Between Inflammation and Thermoregulation

Inflammation is a fundamental immune response that occurs when the body encounters an infection, injury, or other perceived threat. While many associate inflammation with localized symptoms like swelling, redness, and pain, it also triggers a systemic, or body-wide, response. A key aspect of this systemic response is the regulation of body temperature.

The relationship between does inflammation affect body temperature is mediated by specific signaling molecules known as pyrogens. Endogenous pyrogens, such as pro-inflammatory cytokines like interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), are released by immune cells in response to a threat. These cytokines travel through the bloodstream to the brain's hypothalamus, the body's central thermostat. The hypothalamus, in turn, raises the body's set point, initiating a fever.

How Inflammation Causes a Fever

When the hypothalamus raises the body's temperature set point, it sends signals to the rest of the body to generate and conserve heat. This process involves several physiological mechanisms:

Vasoconstriction: Blood vessels in the skin constrict, reducing blood flow to the surface and minimizing heat loss. This is why a person with a fever might feel cold and experience chills.
Shivering: Muscles begin to contract and relax rapidly, which generates heat through metabolic activity. This involuntary shivering helps to raise the body's temperature towards the new, higher set point.
Increased Metabolic Rate: The body's overall metabolism increases, producing more heat as a byproduct.

This elevated body temperature is a strategic defense mechanism. Studies have shown that a mild fever can enhance the efficiency of the immune system by boosting the activity of white blood cells and inhibiting the growth of certain pathogens. However, a fever that is too high or prolonged can be dangerous, potentially causing tissue and organ damage.

The Link Between Systemic Inflammation and Hypothermia

While fever is the more common temperature-related outcome of inflammation, severe systemic inflammation, such as that seen in sepsis, can lead to the opposite response: hypothermia. Hypothermia is a regulated decrease in core body temperature and is a serious clinical sign in critical care.

Unlike fever, the exact mechanism behind inflammation-induced hypothermia is less understood, but it is believed to be a complex, multi-faceted response. In severe cases, the body's immune response can become dysregulated, leading to a massive release of both pro-inflammatory and anti-inflammatory mediators. This chaotic response can overwhelm the body's thermoregulatory center, causing a dangerous drop in temperature.

Acute vs. Chronic Inflammation and Body Temperature

The effect of inflammation on body temperature can differ significantly depending on whether the condition is acute or chronic.

Acute Inflammation

Acute inflammation, typically caused by a short-term infection or injury, is the most common trigger for a fever. The process is usually well-regulated and resolves once the pathogen or injury is addressed. For example, a common cold or a sprained ankle can cause a temporary, manageable temperature increase.

Chronic Inflammation

Chronic inflammation, on the other hand, is a long-term, persistent inflammatory response that can affect the body's thermoregulation in more complex ways. Conditions like autoimmune diseases (e.g., lupus, rheumatoid arthritis) and even certain cancers involve chronic inflammation. In these cases, individuals might experience low-grade fevers that come and go, indicating persistent inflammatory activity. Chronic inflammation can also contribute to a general sense of malaise and fatigue, which is part of the overall immune response. Research also suggests that localized temperature increases in chronic conditions, such as the joints in rheumatoid arthritis, can predict disease progression.

Comparing Temperature Responses to Inflammation


Feature	Fever (Hyperthermia)	Hypothermia	Local Inflammation (Heat)
Cause	Primarily triggered by acute infections or injury, mediated by pro-inflammatory cytokines acting on the hypothalamus.	Result of severe systemic inflammation, such as sepsis, leading to a dysregulated thermoregulatory response.	Direct result of increased blood flow to a specific site of injury or infection.
Mechanism	The brain's hypothalamic thermostat is reset to a higher temperature, causing heat generation and conservation.	The thermoregulatory set point is lowered or overwhelmed, causing the body's core temperature to drop below normal.	Release of inflammatory mediators like histamine, which dilates blood vessels locally, increasing blood flow.
Purpose	A defensive mechanism that can inhibit pathogen growth and boost immune cell activity.	A sign of a severe, potentially life-threatening systemic illness; not a beneficial response.	Part of the immune response to deliver white blood cells and healing factors to the site of damage.
Clinical Sign	Elevated core body temperature (e.g., above 38°C or 100.4°F).	Subnormal core body temperature (e.g., below 36°C or 96.8°F).	Increased skin temperature at the site of inflammation, as measured by touch or thermography.

The Broader Impact and Future Research

The interplay between inflammation and body temperature extends beyond just fever and hypothermia. The elevated temperature associated with a fever can actually boost the activity of certain immune cells, but, as some studies suggest, this can come at a cost. Chronic heat exposure or repeated febrile episodes may promote DNA damage in T cells, which could potentially increase the risk of certain cancers in individuals with persistent inflammation. This highlights the delicate balance of the immune system and the potential consequences of prolonged inflammatory states.

Furthermore, the measurement of temperature is an important diagnostic tool. Advanced techniques like infrared thermography can provide a non-invasive way to visualize and quantify localized inflammation by mapping heat patterns on the body's surface, offering valuable insights into conditions like arthritis.

Conclusion

Understanding the nuanced relationship of does inflammation affect body temperature is key to comprehending the body's complex immune responses. From the familiar and often beneficial fever triggered by acute infection to the dangerous hypothermia that can accompany severe systemic conditions like sepsis, inflammation is a powerful thermoregulatory force. The release of pyrogenic cytokines from immune cells fundamentally alters the brain's temperature set point, leading to a systemic temperature change. This link underscores why monitoring body temperature is a critical aspect of diagnosing and managing infectious and inflammatory diseases. For those with chronic inflammatory conditions, paying attention to persistent low-grade fevers or localized heat can offer important clues about the underlying disease activity and progression.

For more information on the immune system's complex responses, including the role of cytokines, the National Institutes of Health (NIH) website offers extensive resources on immunology and health research.

Frequently Asked Questions

Inflammation causes a fever when immune cells release pyrogenic cytokines like IL-1, IL-6, and TNF-α. These chemicals travel to the brain's hypothalamus, which acts as the body's thermostat, and cause it to raise the body's temperature set point. The body then works to increase its core temperature to this new, higher level.

Yes, chronic inflammation can affect body temperature. While it may not cause a high fever, it can lead to persistent, low-grade temperature elevations or fluctuations. This can be a sign of ongoing inflammatory activity in conditions such as autoimmune diseases or certain types of cancer.

In severe, life-threatening systemic inflammation, such as sepsis, the immune response can become overwhelming and dysregulated. This can disrupt the body's thermoregulatory center, leading to a dangerous drop in core body temperature, or hypothermia.

A systemic fever is a whole-body temperature elevation driven by the brain's thermostat being reset. In contrast, the 'heat' associated with local inflammation is confined to a specific area and is caused by increased blood flow to that site, without changing the body's overall set point.

Yes, a persistent, low-grade temperature elevation can indicate chronic inflammation. More advanced techniques like infrared thermography can also be used to visualize and quantify localized inflammatory heat patterns on the skin, offering objective data for diagnosis and monitoring.

Nonsteroidal anti-inflammatory drugs (NSAIDs) work by inhibiting the production of prostaglandins, which are key mediators in the fever pathway. By blocking this process, NSAIDs can help to reduce a fever caused by inflammation, though they do not address the underlying cause.

Exercise-induced heat can cause a temporary and physiological inflammatory response that helps with tissue repair and adaptation. This differs from the pathogenic inflammation of an illness. However, extreme or prolonged heat stress can induce a more significant inflammatory response.