Recent studies have sparked a debate about what constitutes a normal body temperature, challenging the long-held average of 98.6˚ F (37˚ C). Research suggests a decline in average body temperature over the decades. In a study, the temperature of 96 adults over two weeks ranged from 95.4˚ F (35.2˚ C) to 99.3˚ F (37.4˚ C), indicating a wide variation. This may suggest that what is considered a “normal” body temperature could be less than 98.6˚ F. An analysis of 20 studies from 1935 to 1999 found the average oral temperature to be around 97.5˚ F. Similarly, a study from 2023, along with an earlier study of more than 35,000 people, identified the average body temperature as 97.9˚ F. These findings point to a gradual decrease in normal body temperature over time.

Stanford researchers have also observed a decrease in average human body temperature in the United States since the 1800s, further supporting the notion that the traditional benchmark of 37˚ C (98.6˚ F) might be outdated. Various factors contribute to this change, including improvements in healthcare and changes in lifestyle.

However, a body temperature hovering around 96 or 97 degrees is not necessarily alarming for some. Conditions such as hypothyroidism, diabetes, liver or kidney failure, infection, endocrine dysfunction, and the side effects of certain medications can also lead to a lower body temperature. Excessive alcohol or drug use might contribute as well. It’s important to understand these factors in the context of individual health.

Hypothermia, a condition where body temperature drops below 95˚ F (35˚ C), remains a critical concern. It’s a medical emergency that can occur in very cold temperatures or even in cooler conditions if a person is exposed to rain, sweat, or cold water for long periods.

The time of day also affects body temperature, often being higher in the afternoon than in the morning. A fever is typically defined as a body temperature of 100.4˚ F (38˚ C) or higher, with varying levels of severity.

Other factors like low body weight, muscle mass, skipping meals, and age can influence how one feels in colder temperatures. Older adults, for instance, are more susceptible to hypothermia, even in mildly cold environments.

In conclusion, while the definition of a normal body temperature may be evolving, it’s essential to consider individual variations and health conditions. Understanding these nuances helps in better managing health and responding to symptoms like low body temperature.

Harvard Health
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Stanford University
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University of Rochester Medical Center
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Center for Healthy Aging