Recent studies have indicated a notable shift in what is considered “normal” body temperature, challenging long-standing beliefs. Initially established at 98.6°F (37°C), new research suggests this might not be the average anymore. For instance, a Stanford study highlighted that the average human body temperature in the United States has seen a gradual decrease since the 1800s.

This change in average body temperature raises questions about what constitutes a dangerously low body temperature, traditionally marked as hypothermia when body temperature falls below 95°F (35°C). A Harvard Health publication emphasizes the risks associated with even slight drops in body temperature, especially in cold weather, which can lead to hypothermia. Symptoms of hypothermia include numbness, loss of dexterity, and confusion, and if left untreated, it can be fatal.

A study among 35,000 adults in the United Kingdom discovered an average body temperature lower than the traditional norm, around 97.9°F. Similarly, a 2019 study focused on Americans in Palo Alto, California, found the average to be about 97.5°F. These findings suggest that the “normal” body temperature may vary based on geographic location and population.

Despite these variations, the American Academy of Family Physicians still defines fever as a rise in body temperature of about 1 degree or more over the normal 98.6°F, and hypothermia as a drop below 95°F. The body’s thermostat, the hypothalamus, plays a critical role in maintaining this balance, as explained by Ask A Biologist.

The evolving understanding of what constitutes a normal body temperature underscores the importance of personal health awareness and the need for further research in this area. As our living conditions and health improve, these physiological changes may continue, and our definitions of “normal” may need ongoing adjustments.