Low body temperature is one of those health topics that tends to get oversimplified. Most people grow up believing that 98.6 degrees Fahrenheit is the universal standard for a healthy reading, and that anything below it signals a problem. Low body temperature, however, is more nuanced than that. Normal temperature varies from person to person and typically falls somewhere between 97 and 99 degrees Fahrenheit depending on age, sex, and time of day. Research has even suggested that the average human body temperature may be gradually declining, with 97.5 degrees now considered by some medical professionals to be within the normal range.
A slightly lower reading on its own is usually not cause for alarm. But a consistently low body temperature below 95 degrees means the body may not be generating enough heat to keep the heart, nervous system, and other vital organs functioning properly. At that point, immediate medical attention is warranted. Understanding what triggers low body temperature in the first place can help people know when to act and when to simply monitor.
Six causes of low body temperature worth understanding
Hypothermia
When the body loses heat faster than it can produce it, usually through prolonged exposure to cold environments, the result is hypothermia. Infants and older adults are especially vulnerable because their bodies are less efficient at regulating temperature. Severe cases most often occur in extreme conditions rather than ordinary cold-weather outings. Anyone who suspects hypothermia is setting in should get out of the cold immediately, remove wet clothing, wrap in blankets, and sip warm liquids while avoiding direct heat sources like hot water.
Hypothyroidism
The thyroid gland plays a significant role in temperature regulation by controlling metabolic function. When it underproduces hormones, as happens in hypothyroidism, the body can struggle to maintain warmth. A persistent low reading on the thermometer is sometimes one of the earliest observable signs that something is off with thyroid function, making it a useful diagnostic clue for physicians.
Nervous system disorders
The hypothalamus, a region of the brain, serves as the body’s primary thermostat. Conditions that affect the nervous system, including stroke, spinal cord injury, Parkinson’s disease, and multiple sclerosis, can interfere with how effectively the brain sends and receives the signals needed to regulate temperature. The result can be a chronically lower than normal body reading even in the absence of cold exposure.
Infection or serious illness
While fever is the more widely recognized response to infection, some serious illnesses can trigger the opposite effect. Pneumonia, for example, sometimes produces a low reading particularly in older adults or those with compromised immune systems. A low temperature accompanying infection can indicate sepsis, a dangerous condition in which the body’s inflammatory response to an infection becomes uncontrolled and begins to impair organ function. This situation requires emergency medical care.
Certain medications
Some prescription medications, including antipsychotics used to manage conditions like depression, bipolar disorder, and schizophrenia, can cause a mild but noticeable drop in body temperature as a side effect. Anyone experiencing an unexplained drop in temperature while on medication should raise the issue with their prescribing physician.
Other underlying health conditions
Several less common conditions have also been linked to subnormal temperature readings. These include anorexia nervosa, chronic vitamin B1 deficiency, and certain skin conditions such as erythrodermic psoriasis. Cold temperatures can also raise blood pressure by causing blood vessels to narrow, a factor worth noting for anyone managing cardiovascular health alongside temperature-related concerns.
When to seek medical care
A temperature of 97 degrees with no accompanying symptoms is generally not a reason to call a doctor. But a reading that consistently falls below that threshold, especially when paired with shivering, slurred speech, slow or labored breathing, a weak pulse, confusion, or loss of coordination, requires urgent attention. These can be warning signs of hypothermia or sepsis, both of which are medical emergencies. When in doubt, seek care rather than wait.
