The varying scales of normal body temperature
It's a common misconception that 98.6°F is the universal standard for a normal body temperature. In reality, a person's baseline temperature can vary slightly throughout the day and with age. Recent studies also suggest that the average human body temperature may be slightly decreasing over time. What might be considered low for one person could be normal for another. Normal temperature typically ranges from around 97°F to 99°F, and a reading below this range, especially below 95°F, is more concerning, especially when accompanied by other symptoms.
When a low temperature is not a major concern
In many cases, a slightly low body temperature while you feel under the weather is not an immediate cause for alarm. This can happen due to a variety of less serious factors, including:
- Mild infection: Some mild infections may trigger the body to lower its metabolic rate and core temperature slightly as part of the immune response, or as a result of being inactive.
- Medication side effects: Certain drugs, including some antidepressants or sedatives, can affect the body's ability to regulate its temperature.
- Age-related changes: Older adults and very young children naturally have less ability to regulate their body temperature, making fluctuations more common.
- Hypoglycemia: Low blood sugar can cause a drop in body temperature and is sometimes a side effect of illness, especially in people with diabetes.
Serious causes of a low temperature when sick
While not always serious, a low body temperature can be a red flag for more severe health issues, particularly when accompanied by other symptoms. The most critical concerns are infections that have overwhelmed the body's systems.
Sepsis
Sepsis is a potentially life-threatening condition caused by the body's overwhelming and toxic response to an infection. While a fever is a more common symptom of sepsis, a low body temperature is a recognized and often more dangerous sign, particularly in the very young, elderly, or immunocompromised. A low temperature indicates that the body is no longer able to mount a normal fever response and is essentially in a state of shock.
Hypothermia
While often associated with cold exposure, hypothermia—a dangerously low body temperature below 95°F—can also occur when a person is sick. An overwhelming infection or poor health can compromise the body's internal temperature regulation, leading to a critical drop in core temperature. This is a medical emergency.
Endocrine disorders
Underlying conditions like hypothyroidism, where the thyroid gland is underactive, can cause a consistently low body temperature and heightened sensitivity to cold. A severe illness can exacerbate this issue, making a low temperature more pronounced.
Low body temperature symptom comparison
| Feature | Mild Cause (e.g., viral illness) | Serious Cause (e.g., Sepsis, Hypothermia) |
|---|---|---|
| Temperature Reading | Slightly below typical normal range (e.g., 96-97°F) | Significantly low, often below 95°F (35°C) |
| Mental State | Normal or slightly fatigued/tired | Confusion, drowsiness, slurred speech, memory loss |
| Physical Signs | Might feel a bit chilly, otherwise normal | Uncontrolled shivering (may stop in severe cases), pale or blue skin, weak pulse, slow breathing |
| Energy Level | Low energy, but can function | Extreme exhaustion, clumsiness, lack of coordination |
| Accompanying Symptoms | May have typical cold or flu symptoms | Signs of underlying infection, plus rapid breathing, fast heart rate |
First aid steps for a dangerously low temperature
If you suspect that a low body temperature is a symptom of a serious medical emergency, such as hypothermia or sepsis, take immediate action while waiting for professional help. The Centers for Disease Control and Prevention provides clear guidance on how to help.
- Get medical help: Call 911 or your local emergency number immediately. Inform them of the low temperature and any other symptoms.
- Move the person: Gently move the person to a warmer, drier location if possible. Avoid sudden movements.
- Remove wet clothing: Carefully cut away or remove any wet clothing to prevent further heat loss. Replace with dry layers.
- Warm the person gradually: Use blankets, towels, or even body heat from skin-to-skin contact to warm the center of the person's body—chest, neck, head, and groin. Use an electric blanket if available.
- Provide warm drinks: If the person is conscious and can swallow, offer a warm, sweet, non-alcoholic drink. Do not give them alcohol or caffeine.
- Avoid direct heat: Do not use hot water, heating pads, or heat lamps, as this can cause skin damage and irregular heartbeats.
What to look for and when to act
When you or a loved one are sick, it's vital to monitor not only a fever but also for a low body temperature. While a slightly low reading can be normal, a significant drop or one accompanied by specific symptoms warrants immediate attention. The key is to be aware of the range of what is normal for you and to not dismiss a low reading if other signs suggest something is wrong. Paying close attention to changes in mental state, breathing, and overall energy levels is critical in differentiating a minor issue from a major medical emergency.
For more information on hypothermia, consult an authoritative resource like the Centers for Disease Control and Prevention.
